1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * SLUB: A slab allocator that limits cache line use instead of queuing
   4 * objects in per cpu and per node lists.
   5 *
   6 * The allocator synchronizes using per slab locks or atomic operations
   7 * and only uses a centralized lock to manage a pool of partial slabs.
   8 *
   9 * (C) 2007 SGI, Christoph Lameter
  10 * (C) 2011 Linux Foundation, Christoph Lameter
  11 */
  12
  13#include <linux/mm.h>
  14#include <linux/swap.h> /* mm_account_reclaimed_pages() */
  15#include <linux/module.h>
  16#include <linux/bit_spinlock.h>
  17#include <linux/interrupt.h>
  18#include <linux/swab.h>
  19#include <linux/bitops.h>
  20#include <linux/slab.h>
  21#include "slab.h"
  22#include <linux/proc_fs.h>
  23#include <linux/seq_file.h>
  24#include <linux/kasan.h>
  25#include <linux/kmsan.h>
  26#include <linux/cpu.h>
  27#include <linux/cpuset.h>
  28#include <linux/mempolicy.h>
  29#include <linux/ctype.h>
  30#include <linux/stackdepot.h>
  31#include <linux/debugobjects.h>
  32#include <linux/kallsyms.h>
  33#include <linux/kfence.h>
  34#include <linux/memory.h>
  35#include <linux/math64.h>
  36#include <linux/fault-inject.h>
  37#include <linux/kmemleak.h>
  38#include <linux/stacktrace.h>
  39#include <linux/prefetch.h>
  40#include <linux/memcontrol.h>
  41#include <linux/random.h>
  42#include <kunit/test.h>
  43#include <kunit/test-bug.h>
  44#include <linux/sort.h>
  45
  46#include <linux/debugfs.h>
  47#include <trace/events/kmem.h>
  48
  49#include "internal.h"
  50
  51/*
  52 * Lock order:
  53 *   1. slab_mutex (Global Mutex)
  54 *   2. node->list_lock (Spinlock)
  55 *   3. kmem_cache->cpu_slab->lock (Local lock)
  56 *   4. slab_lock(slab) (Only on some arches)
  57 *   5. object_map_lock (Only for debugging)
  58 *
  59 *   slab_mutex
  60 *
  61 *   The role of the slab_mutex is to protect the list of all the slabs
  62 *   and to synchronize major metadata changes to slab cache structures.
  63 *   Also synchronizes memory hotplug callbacks.
  64 *
  65 *   slab_lock
  66 *
  67 *   The slab_lock is a wrapper around the page lock, thus it is a bit
  68 *   spinlock.
  69 *
  70 *   The slab_lock is only used on arches that do not have the ability
  71 *   to do a cmpxchg_double. It only protects:
  72 *
  73 *	A. slab->freelist	-> List of free objects in a slab
  74 *	B. slab->inuse		-> Number of objects in use
  75 *	C. slab->objects	-> Number of objects in slab
  76 *	D. slab->frozen		-> frozen state
  77 *
  78 *   Frozen slabs
  79 *
  80 *   If a slab is frozen then it is exempt from list management. It is
  81 *   the cpu slab which is actively allocated from by the processor that
  82 *   froze it and it is not on any list. The processor that froze the
  83 *   slab is the one who can perform list operations on the slab. Other
  84 *   processors may put objects onto the freelist but the processor that
  85 *   froze the slab is the only one that can retrieve the objects from the
  86 *   slab's freelist.
  87 *
  88 *   CPU partial slabs
  89 *
  90 *   The partially empty slabs cached on the CPU partial list are used
  91 *   for performance reasons, which speeds up the allocation process.
  92 *   These slabs are not frozen, but are also exempt from list management,
  93 *   by clearing the PG_workingset flag when moving out of the node
  94 *   partial list. Please see __slab_free() for more details.
  95 *
  96 *   To sum up, the current scheme is:
  97 *   - node partial slab: PG_Workingset && !frozen
  98 *   - cpu partial slab: !PG_Workingset && !frozen
  99 *   - cpu slab: !PG_Workingset && frozen
 100 *   - full slab: !PG_Workingset && !frozen
 101 *
 102 *   list_lock
 103 *
 104 *   The list_lock protects the partial and full list on each node and
 105 *   the partial slab counter. If taken then no new slabs may be added or
 106 *   removed from the lists nor make the number of partial slabs be modified.
 107 *   (Note that the total number of slabs is an atomic value that may be
 108 *   modified without taking the list lock).
 109 *
 110 *   The list_lock is a centralized lock and thus we avoid taking it as
 111 *   much as possible. As long as SLUB does not have to handle partial
 112 *   slabs, operations can continue without any centralized lock. F.e.
 113 *   allocating a long series of objects that fill up slabs does not require
 114 *   the list lock.
 115 *
 116 *   For debug caches, all allocations are forced to go through a list_lock
 117 *   protected region to serialize against concurrent validation.
 118 *
 119 *   cpu_slab->lock local lock
 120 *
 121 *   This locks protect slowpath manipulation of all kmem_cache_cpu fields
 122 *   except the stat counters. This is a percpu structure manipulated only by
 123 *   the local cpu, so the lock protects against being preempted or interrupted
 124 *   by an irq. Fast path operations rely on lockless operations instead.
 125 *
 126 *   On PREEMPT_RT, the local lock neither disables interrupts nor preemption
 127 *   which means the lockless fastpath cannot be used as it might interfere with
 128 *   an in-progress slow path operations. In this case the local lock is always
 129 *   taken but it still utilizes the freelist for the common operations.
 130 *
 131 *   lockless fastpaths
 132 *
 133 *   The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
 134 *   are fully lockless when satisfied from the percpu slab (and when
 135 *   cmpxchg_double is possible to use, otherwise slab_lock is taken).
 136 *   They also don't disable preemption or migration or irqs. They rely on
 137 *   the transaction id (tid) field to detect being preempted or moved to
 138 *   another cpu.
 139 *
 140 *   irq, preemption, migration considerations
 141 *
 142 *   Interrupts are disabled as part of list_lock or local_lock operations, or
 143 *   around the slab_lock operation, in order to make the slab allocator safe
 144 *   to use in the context of an irq.
 145 *
 146 *   In addition, preemption (or migration on PREEMPT_RT) is disabled in the
 147 *   allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
 148 *   local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
 149 *   doesn't have to be revalidated in each section protected by the local lock.
 150 *
 151 * SLUB assigns one slab for allocation to each processor.
 152 * Allocations only occur from these slabs called cpu slabs.
 153 *
 154 * Slabs with free elements are kept on a partial list and during regular
 155 * operations no list for full slabs is used. If an object in a full slab is
 156 * freed then the slab will show up again on the partial lists.
 157 * We track full slabs for debugging purposes though because otherwise we
 158 * cannot scan all objects.
 159 *
 160 * Slabs are freed when they become empty. Teardown and setup is
 161 * minimal so we rely on the page allocators per cpu caches for
 162 * fast frees and allocs.
 163 *
 164 * slab->frozen		The slab is frozen and exempt from list processing.
 165 * 			This means that the slab is dedicated to a purpose
 166 * 			such as satisfying allocations for a specific
 167 * 			processor. Objects may be freed in the slab while
 168 * 			it is frozen but slab_free will then skip the usual
 169 * 			list operations. It is up to the processor holding
 170 * 			the slab to integrate the slab into the slab lists
 171 * 			when the slab is no longer needed.
 172 *
 173 * 			One use of this flag is to mark slabs that are
 174 * 			used for allocations. Then such a slab becomes a cpu
 175 * 			slab. The cpu slab may be equipped with an additional
 176 * 			freelist that allows lockless access to
 177 * 			free objects in addition to the regular freelist
 178 * 			that requires the slab lock.
 179 *
 180 * SLAB_DEBUG_FLAGS	Slab requires special handling due to debug
 181 * 			options set. This moves	slab handling out of
 182 * 			the fast path and disables lockless freelists.
 183 */
 184
 185/*
 186 * We could simply use migrate_disable()/enable() but as long as it's a
 187 * function call even on !PREEMPT_RT, use inline preempt_disable() there.
 188 */
 189#ifndef CONFIG_PREEMPT_RT
 190#define slub_get_cpu_ptr(var)		get_cpu_ptr(var)
 191#define slub_put_cpu_ptr(var)		put_cpu_ptr(var)
 192#define USE_LOCKLESS_FAST_PATH()	(true)
 193#else
 194#define slub_get_cpu_ptr(var)		\
 195({					\
 196	migrate_disable();		\
 197	this_cpu_ptr(var);		\
 198})
 199#define slub_put_cpu_ptr(var)		\
 200do {					\
 201	(void)(var);			\
 202	migrate_enable();		\
 203} while (0)
 204#define USE_LOCKLESS_FAST_PATH()	(false)
 205#endif
 206
 207#ifndef CONFIG_SLUB_TINY
 208#define __fastpath_inline __always_inline
 209#else
 210#define __fastpath_inline
 211#endif
 212
 213#ifdef CONFIG_SLUB_DEBUG
 214#ifdef CONFIG_SLUB_DEBUG_ON
 215DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
 216#else
 217DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
 218#endif
 219#endif		/* CONFIG_SLUB_DEBUG */
 220
 221/* Structure holding parameters for get_partial() call chain */
 222struct partial_context {
 223	gfp_t flags;
 224	unsigned int orig_size;
 225	void *object;
 226};
 227
 228static inline bool kmem_cache_debug(struct kmem_cache *s)
 229{
 230	return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
 231}
 232
 233static inline bool slub_debug_orig_size(struct kmem_cache *s)
 234{
 235	return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
 236			(s->flags & SLAB_KMALLOC));
 237}
 238
 239void *fixup_red_left(struct kmem_cache *s, void *p)
 240{
 241	if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
 242		p += s->red_left_pad;
 243
 244	return p;
 245}
 246
 247static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
 248{
 249#ifdef CONFIG_SLUB_CPU_PARTIAL
 250	return !kmem_cache_debug(s);
 251#else
 252	return false;
 253#endif
 254}
 255
 256/*
 257 * Issues still to be resolved:
 258 *
 259 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
 260 *
 261 * - Variable sizing of the per node arrays
 262 */
 263
 264/* Enable to log cmpxchg failures */
 265#undef SLUB_DEBUG_CMPXCHG
 266
 267#ifndef CONFIG_SLUB_TINY
 268/*
 269 * Minimum number of partial slabs. These will be left on the partial
 270 * lists even if they are empty. kmem_cache_shrink may reclaim them.
 271 */
 272#define MIN_PARTIAL 5
 273
 274/*
 275 * Maximum number of desirable partial slabs.
 276 * The existence of more partial slabs makes kmem_cache_shrink
 277 * sort the partial list by the number of objects in use.
 278 */
 279#define MAX_PARTIAL 10
 280#else
 281#define MIN_PARTIAL 0
 282#define MAX_PARTIAL 0
 283#endif
 284
 285#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
 286				SLAB_POISON | SLAB_STORE_USER)
 287
 288/*
 289 * These debug flags cannot use CMPXCHG because there might be consistency
 290 * issues when checking or reading debug information
 291 */
 292#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
 293				SLAB_TRACE)
 294
 295
 296/*
 297 * Debugging flags that require metadata to be stored in the slab.  These get
 298 * disabled when slab_debug=O is used and a cache's min order increases with
 299 * metadata.
 300 */
 301#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 302
 303#define OO_SHIFT	16
 304#define OO_MASK		((1 << OO_SHIFT) - 1)
 305#define MAX_OBJS_PER_PAGE	32767 /* since slab.objects is u15 */
 306
 307/* Internal SLUB flags */
 308/* Poison object */
 309#define __OBJECT_POISON		__SLAB_FLAG_BIT(_SLAB_OBJECT_POISON)
 310/* Use cmpxchg_double */
 311
 312#ifdef system_has_freelist_aba
 313#define __CMPXCHG_DOUBLE	__SLAB_FLAG_BIT(_SLAB_CMPXCHG_DOUBLE)
 314#else
 315#define __CMPXCHG_DOUBLE	__SLAB_FLAG_UNUSED
 316#endif
 317
 318/*
 319 * Tracking user of a slab.
 320 */
 321#define TRACK_ADDRS_COUNT 16
 322struct track {
 323	unsigned long addr;	/* Called from address */
 324#ifdef CONFIG_STACKDEPOT
 325	depot_stack_handle_t handle;
 326#endif
 327	int cpu;		/* Was running on cpu */
 328	int pid;		/* Pid context */
 329	unsigned long when;	/* When did the operation occur */
 330};
 331
 332enum track_item { TRACK_ALLOC, TRACK_FREE };
 333
 334#ifdef SLAB_SUPPORTS_SYSFS
 335static int sysfs_slab_add(struct kmem_cache *);
 336static int sysfs_slab_alias(struct kmem_cache *, const char *);
 337#else
 338static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 339static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
 340							{ return 0; }
 341#endif
 342
 343#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
 344static void debugfs_slab_add(struct kmem_cache *);
 345#else
 346static inline void debugfs_slab_add(struct kmem_cache *s) { }
 347#endif
 348
 349enum stat_item {
 350	ALLOC_FASTPATH,		/* Allocation from cpu slab */
 351	ALLOC_SLOWPATH,		/* Allocation by getting a new cpu slab */
 352	FREE_FASTPATH,		/* Free to cpu slab */
 353	FREE_SLOWPATH,		/* Freeing not to cpu slab */
 354	FREE_FROZEN,		/* Freeing to frozen slab */
 355	FREE_ADD_PARTIAL,	/* Freeing moves slab to partial list */
 356	FREE_REMOVE_PARTIAL,	/* Freeing removes last object */
 357	ALLOC_FROM_PARTIAL,	/* Cpu slab acquired from node partial list */
 358	ALLOC_SLAB,		/* Cpu slab acquired from page allocator */
 359	ALLOC_REFILL,		/* Refill cpu slab from slab freelist */
 360	ALLOC_NODE_MISMATCH,	/* Switching cpu slab */
 361	FREE_SLAB,		/* Slab freed to the page allocator */
 362	CPUSLAB_FLUSH,		/* Abandoning of the cpu slab */
 363	DEACTIVATE_FULL,	/* Cpu slab was full when deactivated */
 364	DEACTIVATE_EMPTY,	/* Cpu slab was empty when deactivated */
 365	DEACTIVATE_TO_HEAD,	/* Cpu slab was moved to the head of partials */
 366	DEACTIVATE_TO_TAIL,	/* Cpu slab was moved to the tail of partials */
 367	DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
 368	DEACTIVATE_BYPASS,	/* Implicit deactivation */
 369	ORDER_FALLBACK,		/* Number of times fallback was necessary */
 370	CMPXCHG_DOUBLE_CPU_FAIL,/* Failures of this_cpu_cmpxchg_double */
 371	CMPXCHG_DOUBLE_FAIL,	/* Failures of slab freelist update */
 372	CPU_PARTIAL_ALLOC,	/* Used cpu partial on alloc */
 373	CPU_PARTIAL_FREE,	/* Refill cpu partial on free */
 374	CPU_PARTIAL_NODE,	/* Refill cpu partial from node partial */
 375	CPU_PARTIAL_DRAIN,	/* Drain cpu partial to node partial */
 376	NR_SLUB_STAT_ITEMS
 377};
 378
 379#ifndef CONFIG_SLUB_TINY
 380/*
 381 * When changing the layout, make sure freelist and tid are still compatible
 382 * with this_cpu_cmpxchg_double() alignment requirements.
 383 */
 384struct kmem_cache_cpu {
 385	union {
 386		struct {
 387			void **freelist;	/* Pointer to next available object */
 388			unsigned long tid;	/* Globally unique transaction id */
 389		};
 390		freelist_aba_t freelist_tid;
 391	};
 392	struct slab *slab;	/* The slab from which we are allocating */
 393#ifdef CONFIG_SLUB_CPU_PARTIAL
 394	struct slab *partial;	/* Partially allocated slabs */
 395#endif
 396	local_lock_t lock;	/* Protects the fields above */
 397#ifdef CONFIG_SLUB_STATS
 398	unsigned int stat[NR_SLUB_STAT_ITEMS];
 399#endif
 400};
 401#endif /* CONFIG_SLUB_TINY */
 402
 403static inline void stat(const struct kmem_cache *s, enum stat_item si)
 404{
 405#ifdef CONFIG_SLUB_STATS
 406	/*
 407	 * The rmw is racy on a preemptible kernel but this is acceptable, so
 408	 * avoid this_cpu_add()'s irq-disable overhead.
 409	 */
 410	raw_cpu_inc(s->cpu_slab->stat[si]);
 411#endif
 412}
 413
 414static inline
 415void stat_add(const struct kmem_cache *s, enum stat_item si, int v)
 416{
 417#ifdef CONFIG_SLUB_STATS
 418	raw_cpu_add(s->cpu_slab->stat[si], v);
 419#endif
 420}
 421
 422/*
 423 * The slab lists for all objects.
 424 */
 425struct kmem_cache_node {
 426	spinlock_t list_lock;
 427	unsigned long nr_partial;
 428	struct list_head partial;
 429#ifdef CONFIG_SLUB_DEBUG
 430	atomic_long_t nr_slabs;
 431	atomic_long_t total_objects;
 432	struct list_head full;
 433#endif
 434};
 435
 436static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 437{
 438	return s->node[node];
 439}
 440
 441/*
 442 * Iterator over all nodes. The body will be executed for each node that has
 443 * a kmem_cache_node structure allocated (which is true for all online nodes)
 444 */
 445#define for_each_kmem_cache_node(__s, __node, __n) \
 446	for (__node = 0; __node < nr_node_ids; __node++) \
 447		 if ((__n = get_node(__s, __node)))
 448
 449/*
 450 * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
 451 * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
 452 * differ during memory hotplug/hotremove operations.
 453 * Protected by slab_mutex.
 454 */
 455static nodemask_t slab_nodes;
 456
 457#ifndef CONFIG_SLUB_TINY
 458/*
 459 * Workqueue used for flush_cpu_slab().
 460 */
 461static struct workqueue_struct *flushwq;
 462#endif
 463
 464/********************************************************************
 465 * 			Core slab cache functions
 466 *******************************************************************/
 467
 468/*
 469 * freeptr_t represents a SLUB freelist pointer, which might be encoded
 470 * and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled.
 471 */
 472typedef struct { unsigned long v; } freeptr_t;
 473
 474/*
 475 * Returns freelist pointer (ptr). With hardening, this is obfuscated
 476 * with an XOR of the address where the pointer is held and a per-cache
 477 * random number.
 478 */
 479static inline freeptr_t freelist_ptr_encode(const struct kmem_cache *s,
 480					    void *ptr, unsigned long ptr_addr)
 481{
 482	unsigned long encoded;
 483
 484#ifdef CONFIG_SLAB_FREELIST_HARDENED
 485	encoded = (unsigned long)ptr ^ s->random ^ swab(ptr_addr);
 
 
 
 
 
 
 
 
 
 
 
 486#else
 487	encoded = (unsigned long)ptr;
 488#endif
 489	return (freeptr_t){.v = encoded};
 490}
 491
 492static inline void *freelist_ptr_decode(const struct kmem_cache *s,
 493					freeptr_t ptr, unsigned long ptr_addr)
 
 494{
 495	void *decoded;
 496
 497#ifdef CONFIG_SLAB_FREELIST_HARDENED
 498	decoded = (void *)(ptr.v ^ s->random ^ swab(ptr_addr));
 499#else
 500	decoded = (void *)ptr.v;
 501#endif
 502	return decoded;
 503}
 504
 505static inline void *get_freepointer(struct kmem_cache *s, void *object)
 506{
 507	unsigned long ptr_addr;
 508	freeptr_t p;
 509
 510	object = kasan_reset_tag(object);
 511	ptr_addr = (unsigned long)object + s->offset;
 512	p = *(freeptr_t *)(ptr_addr);
 513	return freelist_ptr_decode(s, p, ptr_addr);
 514}
 515
 516#ifndef CONFIG_SLUB_TINY
 517static void prefetch_freepointer(const struct kmem_cache *s, void *object)
 518{
 519	prefetchw(object + s->offset);
 520}
 521#endif
 522
 523/*
 524 * When running under KMSAN, get_freepointer_safe() may return an uninitialized
 525 * pointer value in the case the current thread loses the race for the next
 526 * memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in
 527 * slab_alloc_node() will fail, so the uninitialized value won't be used, but
 528 * KMSAN will still check all arguments of cmpxchg because of imperfect
 529 * handling of inline assembly.
 530 * To work around this problem, we apply __no_kmsan_checks to ensure that
 531 * get_freepointer_safe() returns initialized memory.
 532 */
 533__no_kmsan_checks
 534static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 535{
 536	unsigned long freepointer_addr;
 537	freeptr_t p;
 538
 539	if (!debug_pagealloc_enabled_static())
 540		return get_freepointer(s, object);
 541
 542	object = kasan_reset_tag(object);
 543	freepointer_addr = (unsigned long)object + s->offset;
 544	copy_from_kernel_nofault(&p, (freeptr_t *)freepointer_addr, sizeof(p));
 545	return freelist_ptr_decode(s, p, freepointer_addr);
 546}
 547
 548static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
 549{
 550	unsigned long freeptr_addr = (unsigned long)object + s->offset;
 551
 552#ifdef CONFIG_SLAB_FREELIST_HARDENED
 553	BUG_ON(object == fp); /* naive detection of double free or corruption */
 554#endif
 555
 556	freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
 557	*(freeptr_t *)freeptr_addr = freelist_ptr_encode(s, fp, freeptr_addr);
 558}
 559
 560/*
 561 * See comment in calculate_sizes().
 562 */
 563static inline bool freeptr_outside_object(struct kmem_cache *s)
 564{
 565	return s->offset >= s->inuse;
 566}
 567
 568/*
 569 * Return offset of the end of info block which is inuse + free pointer if
 570 * not overlapping with object.
 571 */
 572static inline unsigned int get_info_end(struct kmem_cache *s)
 573{
 574	if (freeptr_outside_object(s))
 575		return s->inuse + sizeof(void *);
 576	else
 577		return s->inuse;
 578}
 579
 580/* Loop over all objects in a slab */
 581#define for_each_object(__p, __s, __addr, __objects) \
 582	for (__p = fixup_red_left(__s, __addr); \
 583		__p < (__addr) + (__objects) * (__s)->size; \
 584		__p += (__s)->size)
 585
 586static inline unsigned int order_objects(unsigned int order, unsigned int size)
 587{
 588	return ((unsigned int)PAGE_SIZE << order) / size;
 589}
 590
 591static inline struct kmem_cache_order_objects oo_make(unsigned int order,
 592		unsigned int size)
 593{
 594	struct kmem_cache_order_objects x = {
 595		(order << OO_SHIFT) + order_objects(order, size)
 596	};
 597
 598	return x;
 599}
 600
 601static inline unsigned int oo_order(struct kmem_cache_order_objects x)
 602{
 603	return x.x >> OO_SHIFT;
 604}
 605
 606static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
 607{
 608	return x.x & OO_MASK;
 609}
 610
 611#ifdef CONFIG_SLUB_CPU_PARTIAL
 612static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
 613{
 614	unsigned int nr_slabs;
 615
 616	s->cpu_partial = nr_objects;
 617
 618	/*
 619	 * We take the number of objects but actually limit the number of
 620	 * slabs on the per cpu partial list, in order to limit excessive
 621	 * growth of the list. For simplicity we assume that the slabs will
 622	 * be half-full.
 623	 */
 624	nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
 625	s->cpu_partial_slabs = nr_slabs;
 626}
 627#else
 628static inline void
 629slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
 630{
 631}
 632#endif /* CONFIG_SLUB_CPU_PARTIAL */
 633
 634/*
 635 * Per slab locking using the pagelock
 636 */
 637static __always_inline void slab_lock(struct slab *slab)
 638{
 639	struct page *page = slab_page(slab);
 640
 641	VM_BUG_ON_PAGE(PageTail(page), page);
 642	bit_spin_lock(PG_locked, &page->flags);
 643}
 644
 645static __always_inline void slab_unlock(struct slab *slab)
 646{
 647	struct page *page = slab_page(slab);
 648
 649	VM_BUG_ON_PAGE(PageTail(page), page);
 650	bit_spin_unlock(PG_locked, &page->flags);
 651}
 652
 653static inline bool
 654__update_freelist_fast(struct slab *slab,
 655		      void *freelist_old, unsigned long counters_old,
 656		      void *freelist_new, unsigned long counters_new)
 657{
 658#ifdef system_has_freelist_aba
 659	freelist_aba_t old = { .freelist = freelist_old, .counter = counters_old };
 660	freelist_aba_t new = { .freelist = freelist_new, .counter = counters_new };
 661
 662	return try_cmpxchg_freelist(&slab->freelist_counter.full, &old.full, new.full);
 663#else
 664	return false;
 665#endif
 666}
 667
 668static inline bool
 669__update_freelist_slow(struct slab *slab,
 670		      void *freelist_old, unsigned long counters_old,
 671		      void *freelist_new, unsigned long counters_new)
 672{
 673	bool ret = false;
 674
 675	slab_lock(slab);
 676	if (slab->freelist == freelist_old &&
 677	    slab->counters == counters_old) {
 678		slab->freelist = freelist_new;
 679		slab->counters = counters_new;
 680		ret = true;
 681	}
 682	slab_unlock(slab);
 683
 684	return ret;
 685}
 686
 687/*
 688 * Interrupts must be disabled (for the fallback code to work right), typically
 689 * by an _irqsave() lock variant. On PREEMPT_RT the preempt_disable(), which is
 690 * part of bit_spin_lock(), is sufficient because the policy is not to allow any
 691 * allocation/ free operation in hardirq context. Therefore nothing can
 692 * interrupt the operation.
 693 */
 694static inline bool __slab_update_freelist(struct kmem_cache *s, struct slab *slab,
 695		void *freelist_old, unsigned long counters_old,
 696		void *freelist_new, unsigned long counters_new,
 697		const char *n)
 698{
 699	bool ret;
 700
 701	if (USE_LOCKLESS_FAST_PATH())
 702		lockdep_assert_irqs_disabled();
 703
 704	if (s->flags & __CMPXCHG_DOUBLE) {
 705		ret = __update_freelist_fast(slab, freelist_old, counters_old,
 706				            freelist_new, counters_new);
 707	} else {
 708		ret = __update_freelist_slow(slab, freelist_old, counters_old,
 709				            freelist_new, counters_new);
 
 
 
 
 
 
 
 
 
 
 
 710	}
 711	if (likely(ret))
 712		return true;
 713
 714	cpu_relax();
 715	stat(s, CMPXCHG_DOUBLE_FAIL);
 716
 717#ifdef SLUB_DEBUG_CMPXCHG
 718	pr_info("%s %s: cmpxchg double redo ", n, s->name);
 719#endif
 720
 721	return false;
 722}
 723
 724static inline bool slab_update_freelist(struct kmem_cache *s, struct slab *slab,
 725		void *freelist_old, unsigned long counters_old,
 726		void *freelist_new, unsigned long counters_new,
 727		const char *n)
 728{
 729	bool ret;
 730
 731	if (s->flags & __CMPXCHG_DOUBLE) {
 732		ret = __update_freelist_fast(slab, freelist_old, counters_old,
 733				            freelist_new, counters_new);
 734	} else {
 
 
 
 
 735		unsigned long flags;
 736
 737		local_irq_save(flags);
 738		ret = __update_freelist_slow(slab, freelist_old, counters_old,
 739				            freelist_new, counters_new);
 
 
 
 
 
 
 
 
 740		local_irq_restore(flags);
 741	}
 742	if (likely(ret))
 743		return true;
 744
 745	cpu_relax();
 746	stat(s, CMPXCHG_DOUBLE_FAIL);
 747
 748#ifdef SLUB_DEBUG_CMPXCHG
 749	pr_info("%s %s: cmpxchg double redo ", n, s->name);
 750#endif
 751
 752	return false;
 753}
 754
 755#ifdef CONFIG_SLUB_DEBUG
 756static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
 757static DEFINE_SPINLOCK(object_map_lock);
 758
 759static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
 760		       struct slab *slab)
 761{
 762	void *addr = slab_address(slab);
 763	void *p;
 764
 765	bitmap_zero(obj_map, slab->objects);
 766
 767	for (p = slab->freelist; p; p = get_freepointer(s, p))
 768		set_bit(__obj_to_index(s, addr, p), obj_map);
 769}
 770
 771#if IS_ENABLED(CONFIG_KUNIT)
 772static bool slab_add_kunit_errors(void)
 773{
 774	struct kunit_resource *resource;
 775
 776	if (!kunit_get_current_test())
 777		return false;
 778
 779	resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
 780	if (!resource)
 781		return false;
 782
 783	(*(int *)resource->data)++;
 784	kunit_put_resource(resource);
 785	return true;
 786}
 787#else
 788static inline bool slab_add_kunit_errors(void) { return false; }
 789#endif
 790
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 791static inline unsigned int size_from_object(struct kmem_cache *s)
 792{
 793	if (s->flags & SLAB_RED_ZONE)
 794		return s->size - s->red_left_pad;
 795
 796	return s->size;
 797}
 798
 799static inline void *restore_red_left(struct kmem_cache *s, void *p)
 800{
 801	if (s->flags & SLAB_RED_ZONE)
 802		p -= s->red_left_pad;
 803
 804	return p;
 805}
 806
 807/*
 808 * Debug settings:
 809 */
 810#if defined(CONFIG_SLUB_DEBUG_ON)
 811static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
 812#else
 813static slab_flags_t slub_debug;
 814#endif
 815
 816static char *slub_debug_string;
 817static int disable_higher_order_debug;
 818
 819/*
 820 * slub is about to manipulate internal object metadata.  This memory lies
 821 * outside the range of the allocated object, so accessing it would normally
 822 * be reported by kasan as a bounds error.  metadata_access_enable() is used
 823 * to tell kasan that these accesses are OK.
 824 */
 825static inline void metadata_access_enable(void)
 826{
 827	kasan_disable_current();
 828}
 829
 830static inline void metadata_access_disable(void)
 831{
 832	kasan_enable_current();
 833}
 834
 835/*
 836 * Object debugging
 837 */
 838
 839/* Verify that a pointer has an address that is valid within a slab page */
 840static inline int check_valid_pointer(struct kmem_cache *s,
 841				struct slab *slab, void *object)
 842{
 843	void *base;
 844
 845	if (!object)
 846		return 1;
 847
 848	base = slab_address(slab);
 849	object = kasan_reset_tag(object);
 850	object = restore_red_left(s, object);
 851	if (object < base || object >= base + slab->objects * s->size ||
 852		(object - base) % s->size) {
 853		return 0;
 854	}
 855
 856	return 1;
 857}
 858
 859static void print_section(char *level, char *text, u8 *addr,
 860			  unsigned int length)
 861{
 862	metadata_access_enable();
 863	print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
 864			16, 1, kasan_reset_tag((void *)addr), length, 1);
 865	metadata_access_disable();
 866}
 867
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 868static struct track *get_track(struct kmem_cache *s, void *object,
 869	enum track_item alloc)
 870{
 871	struct track *p;
 872
 873	p = object + get_info_end(s);
 874
 875	return kasan_reset_tag(p + alloc);
 876}
 877
 878#ifdef CONFIG_STACKDEPOT
 879static noinline depot_stack_handle_t set_track_prepare(void)
 880{
 881	depot_stack_handle_t handle;
 882	unsigned long entries[TRACK_ADDRS_COUNT];
 883	unsigned int nr_entries;
 884
 885	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
 886	handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
 887
 888	return handle;
 889}
 890#else
 891static inline depot_stack_handle_t set_track_prepare(void)
 892{
 893	return 0;
 894}
 895#endif
 896
 897static void set_track_update(struct kmem_cache *s, void *object,
 898			     enum track_item alloc, unsigned long addr,
 899			     depot_stack_handle_t handle)
 900{
 901	struct track *p = get_track(s, object, alloc);
 902
 903#ifdef CONFIG_STACKDEPOT
 904	p->handle = handle;
 905#endif
 906	p->addr = addr;
 907	p->cpu = smp_processor_id();
 908	p->pid = current->pid;
 909	p->when = jiffies;
 910}
 911
 912static __always_inline void set_track(struct kmem_cache *s, void *object,
 913				      enum track_item alloc, unsigned long addr)
 914{
 915	depot_stack_handle_t handle = set_track_prepare();
 916
 917	set_track_update(s, object, alloc, addr, handle);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 918}
 919
 920static void init_tracking(struct kmem_cache *s, void *object)
 921{
 922	struct track *p;
 923
 924	if (!(s->flags & SLAB_STORE_USER))
 925		return;
 926
 927	p = get_track(s, object, TRACK_ALLOC);
 928	memset(p, 0, 2*sizeof(struct track));
 929}
 930
 931static void print_track(const char *s, struct track *t, unsigned long pr_time)
 932{
 933	depot_stack_handle_t handle __maybe_unused;
 934
 935	if (!t->addr)
 936		return;
 937
 938	pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
 939	       s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
 940#ifdef CONFIG_STACKDEPOT
 941	handle = READ_ONCE(t->handle);
 942	if (handle)
 943		stack_depot_print(handle);
 944	else
 945		pr_err("object allocation/free stack trace missing\n");
 
 
 
 946#endif
 947}
 948
 949void print_tracking(struct kmem_cache *s, void *object)
 950{
 951	unsigned long pr_time = jiffies;
 952	if (!(s->flags & SLAB_STORE_USER))
 953		return;
 954
 955	print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
 956	print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
 957}
 958
 959static void print_slab_info(const struct slab *slab)
 960{
 961	struct folio *folio = (struct folio *)slab_folio(slab);
 962
 963	pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
 964	       slab, slab->objects, slab->inuse, slab->freelist,
 965	       folio_flags(folio, 0));
 966}
 967
 968/*
 969 * kmalloc caches has fixed sizes (mostly power of 2), and kmalloc() API
 970 * family will round up the real request size to these fixed ones, so
 971 * there could be an extra area than what is requested. Save the original
 972 * request size in the meta data area, for better debug and sanity check.
 973 */
 974static inline void set_orig_size(struct kmem_cache *s,
 975				void *object, unsigned int orig_size)
 976{
 977	void *p = kasan_reset_tag(object);
 978	unsigned int kasan_meta_size;
 979
 980	if (!slub_debug_orig_size(s))
 981		return;
 982
 983	/*
 984	 * KASAN can save its free meta data inside of the object at offset 0.
 985	 * If this meta data size is larger than 'orig_size', it will overlap
 986	 * the data redzone in [orig_size+1, object_size]. Thus, we adjust
 987	 * 'orig_size' to be as at least as big as KASAN's meta data.
 988	 */
 989	kasan_meta_size = kasan_metadata_size(s, true);
 990	if (kasan_meta_size > orig_size)
 991		orig_size = kasan_meta_size;
 992
 993	p += get_info_end(s);
 994	p += sizeof(struct track) * 2;
 995
 996	*(unsigned int *)p = orig_size;
 997}
 998
 999static inline unsigned int get_orig_size(struct kmem_cache *s, void *object)
1000{
1001	void *p = kasan_reset_tag(object);
1002
1003	if (!slub_debug_orig_size(s))
1004		return s->object_size;
1005
1006	p += get_info_end(s);
1007	p += sizeof(struct track) * 2;
1008
1009	return *(unsigned int *)p;
1010}
1011
1012void skip_orig_size_check(struct kmem_cache *s, const void *object)
1013{
1014	set_orig_size(s, (void *)object, s->object_size);
1015}
1016
1017static void slab_bug(struct kmem_cache *s, char *fmt, ...)
1018{
1019	struct va_format vaf;
1020	va_list args;
1021
1022	va_start(args, fmt);
1023	vaf.fmt = fmt;
1024	vaf.va = &args;
1025	pr_err("=============================================================================\n");
1026	pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
1027	pr_err("-----------------------------------------------------------------------------\n\n");
1028	va_end(args);
1029}
1030
1031__printf(2, 3)
1032static void slab_fix(struct kmem_cache *s, char *fmt, ...)
1033{
1034	struct va_format vaf;
1035	va_list args;
1036
1037	if (slab_add_kunit_errors())
1038		return;
1039
1040	va_start(args, fmt);
1041	vaf.fmt = fmt;
1042	vaf.va = &args;
1043	pr_err("FIX %s: %pV\n", s->name, &vaf);
1044	va_end(args);
1045}
1046
1047static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1048{
1049	unsigned int off;	/* Offset of last byte */
1050	u8 *addr = slab_address(slab);
1051
1052	print_tracking(s, p);
1053
1054	print_slab_info(slab);
1055
1056	pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
1057	       p, p - addr, get_freepointer(s, p));
1058
1059	if (s->flags & SLAB_RED_ZONE)
1060		print_section(KERN_ERR, "Redzone  ", p - s->red_left_pad,
1061			      s->red_left_pad);
1062	else if (p > addr + 16)
1063		print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
1064
1065	print_section(KERN_ERR,         "Object   ", p,
1066		      min_t(unsigned int, s->object_size, PAGE_SIZE));
1067	if (s->flags & SLAB_RED_ZONE)
1068		print_section(KERN_ERR, "Redzone  ", p + s->object_size,
1069			s->inuse - s->object_size);
1070
1071	off = get_info_end(s);
1072
1073	if (s->flags & SLAB_STORE_USER)
1074		off += 2 * sizeof(struct track);
1075
1076	if (slub_debug_orig_size(s))
1077		off += sizeof(unsigned int);
1078
1079	off += kasan_metadata_size(s, false);
1080
1081	if (off != size_from_object(s))
1082		/* Beginning of the filler is the free pointer */
1083		print_section(KERN_ERR, "Padding  ", p + off,
1084			      size_from_object(s) - off);
1085
1086	dump_stack();
1087}
1088
1089static void object_err(struct kmem_cache *s, struct slab *slab,
1090			u8 *object, char *reason)
1091{
1092	if (slab_add_kunit_errors())
1093		return;
1094
1095	slab_bug(s, "%s", reason);
1096	print_trailer(s, slab, object);
1097	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1098}
1099
1100static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
1101			       void **freelist, void *nextfree)
1102{
1103	if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
1104	    !check_valid_pointer(s, slab, nextfree) && freelist) {
1105		object_err(s, slab, *freelist, "Freechain corrupt");
1106		*freelist = NULL;
1107		slab_fix(s, "Isolate corrupted freechain");
1108		return true;
1109	}
1110
1111	return false;
1112}
1113
1114static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
1115			const char *fmt, ...)
1116{
1117	va_list args;
1118	char buf[100];
1119
1120	if (slab_add_kunit_errors())
1121		return;
1122
1123	va_start(args, fmt);
1124	vsnprintf(buf, sizeof(buf), fmt, args);
1125	va_end(args);
1126	slab_bug(s, "%s", buf);
1127	print_slab_info(slab);
1128	dump_stack();
1129	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1130}
1131
1132static void init_object(struct kmem_cache *s, void *object, u8 val)
1133{
1134	u8 *p = kasan_reset_tag(object);
1135	unsigned int poison_size = s->object_size;
1136
1137	if (s->flags & SLAB_RED_ZONE) {
1138		memset(p - s->red_left_pad, val, s->red_left_pad);
1139
1140		if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
1141			/*
1142			 * Redzone the extra allocated space by kmalloc than
1143			 * requested, and the poison size will be limited to
1144			 * the original request size accordingly.
1145			 */
1146			poison_size = get_orig_size(s, object);
1147		}
1148	}
1149
1150	if (s->flags & __OBJECT_POISON) {
1151		memset(p, POISON_FREE, poison_size - 1);
1152		p[poison_size - 1] = POISON_END;
1153	}
1154
1155	if (s->flags & SLAB_RED_ZONE)
1156		memset(p + poison_size, val, s->inuse - poison_size);
1157}
1158
1159static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
1160						void *from, void *to)
1161{
1162	slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data);
1163	memset(from, data, to - from);
1164}
1165
1166static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
1167			u8 *object, char *what,
1168			u8 *start, unsigned int value, unsigned int bytes)
1169{
1170	u8 *fault;
1171	u8 *end;
1172	u8 *addr = slab_address(slab);
1173
1174	metadata_access_enable();
1175	fault = memchr_inv(kasan_reset_tag(start), value, bytes);
1176	metadata_access_disable();
1177	if (!fault)
1178		return 1;
1179
1180	end = start + bytes;
1181	while (end > fault && end[-1] == value)
1182		end--;
1183
1184	if (slab_add_kunit_errors())
1185		goto skip_bug_print;
1186
1187	slab_bug(s, "%s overwritten", what);
1188	pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
1189					fault, end - 1, fault - addr,
1190					fault[0], value);
1191	print_trailer(s, slab, object);
1192	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1193
1194skip_bug_print:
1195	restore_bytes(s, what, value, fault, end);
1196	return 0;
1197}
1198
1199/*
1200 * Object layout:
1201 *
1202 * object address
1203 * 	Bytes of the object to be managed.
1204 * 	If the freepointer may overlay the object then the free
1205 *	pointer is at the middle of the object.
1206 *
1207 * 	Poisoning uses 0x6b (POISON_FREE) and the last byte is
1208 * 	0xa5 (POISON_END)
1209 *
1210 * object + s->object_size
1211 * 	Padding to reach word boundary. This is also used for Redzoning.
1212 * 	Padding is extended by another word if Redzoning is enabled and
1213 * 	object_size == inuse.
1214 *
1215 * 	We fill with 0xbb (RED_INACTIVE) for inactive objects and with
1216 * 	0xcc (RED_ACTIVE) for objects in use.
1217 *
1218 * object + s->inuse
1219 * 	Meta data starts here.
1220 *
1221 * 	A. Free pointer (if we cannot overwrite object on free)
1222 * 	B. Tracking data for SLAB_STORE_USER
1223 *	C. Original request size for kmalloc object (SLAB_STORE_USER enabled)
1224 *	D. Padding to reach required alignment boundary or at minimum
1225 * 		one word if debugging is on to be able to detect writes
1226 * 		before the word boundary.
1227 *
1228 *	Padding is done using 0x5a (POISON_INUSE)
1229 *
1230 * object + s->size
1231 * 	Nothing is used beyond s->size.
1232 *
1233 * If slabcaches are merged then the object_size and inuse boundaries are mostly
1234 * ignored. And therefore no slab options that rely on these boundaries
1235 * may be used with merged slabcaches.
1236 */
1237
1238static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
1239{
1240	unsigned long off = get_info_end(s);	/* The end of info */
1241
1242	if (s->flags & SLAB_STORE_USER) {
1243		/* We also have user information there */
1244		off += 2 * sizeof(struct track);
1245
1246		if (s->flags & SLAB_KMALLOC)
1247			off += sizeof(unsigned int);
1248	}
1249
1250	off += kasan_metadata_size(s, false);
1251
1252	if (size_from_object(s) == off)
1253		return 1;
1254
1255	return check_bytes_and_report(s, slab, p, "Object padding",
1256			p + off, POISON_INUSE, size_from_object(s) - off);
1257}
1258
1259/* Check the pad bytes at the end of a slab page */
1260static void slab_pad_check(struct kmem_cache *s, struct slab *slab)
1261{
1262	u8 *start;
1263	u8 *fault;
1264	u8 *end;
1265	u8 *pad;
1266	int length;
1267	int remainder;
1268
1269	if (!(s->flags & SLAB_POISON))
1270		return;
1271
1272	start = slab_address(slab);
1273	length = slab_size(slab);
1274	end = start + length;
1275	remainder = length % s->size;
1276	if (!remainder)
1277		return;
1278
1279	pad = end - remainder;
1280	metadata_access_enable();
1281	fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
1282	metadata_access_disable();
1283	if (!fault)
1284		return;
1285	while (end > fault && end[-1] == POISON_INUSE)
1286		end--;
1287
1288	slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
1289			fault, end - 1, fault - start);
1290	print_section(KERN_ERR, "Padding ", pad, remainder);
1291
1292	restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
 
1293}
1294
1295static int check_object(struct kmem_cache *s, struct slab *slab,
1296					void *object, u8 val)
1297{
1298	u8 *p = object;
1299	u8 *endobject = object + s->object_size;
1300	unsigned int orig_size, kasan_meta_size;
1301
1302	if (s->flags & SLAB_RED_ZONE) {
1303		if (!check_bytes_and_report(s, slab, object, "Left Redzone",
1304			object - s->red_left_pad, val, s->red_left_pad))
1305			return 0;
1306
1307		if (!check_bytes_and_report(s, slab, object, "Right Redzone",
1308			endobject, val, s->inuse - s->object_size))
1309			return 0;
1310
1311		if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
1312			orig_size = get_orig_size(s, object);
1313
1314			if (s->object_size > orig_size  &&
1315				!check_bytes_and_report(s, slab, object,
1316					"kmalloc Redzone", p + orig_size,
1317					val, s->object_size - orig_size)) {
1318				return 0;
1319			}
1320		}
1321	} else {
1322		if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
1323			check_bytes_and_report(s, slab, p, "Alignment padding",
1324				endobject, POISON_INUSE,
1325				s->inuse - s->object_size);
1326		}
1327	}
1328
1329	if (s->flags & SLAB_POISON) {
1330		if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON)) {
1331			/*
1332			 * KASAN can save its free meta data inside of the
1333			 * object at offset 0. Thus, skip checking the part of
1334			 * the redzone that overlaps with the meta data.
1335			 */
1336			kasan_meta_size = kasan_metadata_size(s, true);
1337			if (kasan_meta_size < s->object_size - 1 &&
1338			    !check_bytes_and_report(s, slab, p, "Poison",
1339					p + kasan_meta_size, POISON_FREE,
1340					s->object_size - kasan_meta_size - 1))
1341				return 0;
1342			if (kasan_meta_size < s->object_size &&
1343			    !check_bytes_and_report(s, slab, p, "End Poison",
1344					p + s->object_size - 1, POISON_END, 1))
1345				return 0;
1346		}
1347		/*
1348		 * check_pad_bytes cleans up on its own.
1349		 */
1350		check_pad_bytes(s, slab, p);
1351	}
1352
1353	if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
1354		/*
1355		 * Object and freepointer overlap. Cannot check
1356		 * freepointer while object is allocated.
1357		 */
1358		return 1;
1359
1360	/* Check free pointer validity */
1361	if (!check_valid_pointer(s, slab, get_freepointer(s, p))) {
1362		object_err(s, slab, p, "Freepointer corrupt");
1363		/*
1364		 * No choice but to zap it and thus lose the remainder
1365		 * of the free objects in this slab. May cause
1366		 * another error because the object count is now wrong.
1367		 */
1368		set_freepointer(s, p, NULL);
1369		return 0;
1370	}
1371	return 1;
1372}
1373
1374static int check_slab(struct kmem_cache *s, struct slab *slab)
1375{
1376	int maxobj;
1377
1378	if (!folio_test_slab(slab_folio(slab))) {
1379		slab_err(s, slab, "Not a valid slab page");
 
 
1380		return 0;
1381	}
1382
1383	maxobj = order_objects(slab_order(slab), s->size);
1384	if (slab->objects > maxobj) {
1385		slab_err(s, slab, "objects %u > max %u",
1386			slab->objects, maxobj);
1387		return 0;
1388	}
1389	if (slab->inuse > slab->objects) {
1390		slab_err(s, slab, "inuse %u > max %u",
1391			slab->inuse, slab->objects);
1392		return 0;
1393	}
1394	/* Slab_pad_check fixes things up after itself */
1395	slab_pad_check(s, slab);
1396	return 1;
1397}
1398
1399/*
1400 * Determine if a certain object in a slab is on the freelist. Must hold the
1401 * slab lock to guarantee that the chains are in a consistent state.
1402 */
1403static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
1404{
1405	int nr = 0;
1406	void *fp;
1407	void *object = NULL;
1408	int max_objects;
1409
1410	fp = slab->freelist;
1411	while (fp && nr <= slab->objects) {
1412		if (fp == search)
1413			return 1;
1414		if (!check_valid_pointer(s, slab, fp)) {
1415			if (object) {
1416				object_err(s, slab, object,
1417					"Freechain corrupt");
1418				set_freepointer(s, object, NULL);
1419			} else {
1420				slab_err(s, slab, "Freepointer corrupt");
1421				slab->freelist = NULL;
1422				slab->inuse = slab->objects;
1423				slab_fix(s, "Freelist cleared");
1424				return 0;
1425			}
1426			break;
1427		}
1428		object = fp;
1429		fp = get_freepointer(s, object);
1430		nr++;
1431	}
1432
1433	max_objects = order_objects(slab_order(slab), s->size);
1434	if (max_objects > MAX_OBJS_PER_PAGE)
1435		max_objects = MAX_OBJS_PER_PAGE;
1436
1437	if (slab->objects != max_objects) {
1438		slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
1439			 slab->objects, max_objects);
1440		slab->objects = max_objects;
1441		slab_fix(s, "Number of objects adjusted");
1442	}
1443	if (slab->inuse != slab->objects - nr) {
1444		slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
1445			 slab->inuse, slab->objects - nr);
1446		slab->inuse = slab->objects - nr;
1447		slab_fix(s, "Object count adjusted");
1448	}
1449	return search == NULL;
1450}
1451
1452static void trace(struct kmem_cache *s, struct slab *slab, void *object,
1453								int alloc)
1454{
1455	if (s->flags & SLAB_TRACE) {
1456		pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1457			s->name,
1458			alloc ? "alloc" : "free",
1459			object, slab->inuse,
1460			slab->freelist);
1461
1462		if (!alloc)
1463			print_section(KERN_INFO, "Object ", (void *)object,
1464					s->object_size);
1465
1466		dump_stack();
1467	}
1468}
1469
1470/*
1471 * Tracking of fully allocated slabs for debugging purposes.
1472 */
1473static void add_full(struct kmem_cache *s,
1474	struct kmem_cache_node *n, struct slab *slab)
1475{
1476	if (!(s->flags & SLAB_STORE_USER))
1477		return;
1478
1479	lockdep_assert_held(&n->list_lock);
1480	list_add(&slab->slab_list, &n->full);
1481}
1482
1483static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
1484{
1485	if (!(s->flags & SLAB_STORE_USER))
1486		return;
1487
1488	lockdep_assert_held(&n->list_lock);
1489	list_del(&slab->slab_list);
 
 
 
 
 
 
 
 
1490}
1491
1492static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1493{
1494	return atomic_long_read(&n->nr_slabs);
1495}
1496
1497static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1498{
1499	struct kmem_cache_node *n = get_node(s, node);
1500
1501	atomic_long_inc(&n->nr_slabs);
1502	atomic_long_add(objects, &n->total_objects);
 
 
 
 
 
 
 
 
1503}
1504static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1505{
1506	struct kmem_cache_node *n = get_node(s, node);
1507
1508	atomic_long_dec(&n->nr_slabs);
1509	atomic_long_sub(objects, &n->total_objects);
1510}
1511
1512/* Object debug checks for alloc/free paths */
1513static void setup_object_debug(struct kmem_cache *s, void *object)
 
1514{
1515	if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
1516		return;
1517
1518	init_object(s, object, SLUB_RED_INACTIVE);
1519	init_tracking(s, object);
1520}
1521
1522static
1523void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
1524{
1525	if (!kmem_cache_debug_flags(s, SLAB_POISON))
1526		return;
1527
1528	metadata_access_enable();
1529	memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
1530	metadata_access_disable();
1531}
1532
1533static inline int alloc_consistency_checks(struct kmem_cache *s,
1534					struct slab *slab, void *object)
1535{
1536	if (!check_slab(s, slab))
1537		return 0;
1538
1539	if (!check_valid_pointer(s, slab, object)) {
1540		object_err(s, slab, object, "Freelist Pointer check fails");
1541		return 0;
1542	}
1543
1544	if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
1545		return 0;
1546
1547	return 1;
1548}
1549
1550static noinline bool alloc_debug_processing(struct kmem_cache *s,
1551			struct slab *slab, void *object, int orig_size)
 
1552{
1553	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1554		if (!alloc_consistency_checks(s, slab, object))
1555			goto bad;
1556	}
1557
1558	/* Success. Perform special debug activities for allocs */
1559	trace(s, slab, object, 1);
1560	set_orig_size(s, object, orig_size);
 
1561	init_object(s, object, SLUB_RED_ACTIVE);
1562	return true;
1563
1564bad:
1565	if (folio_test_slab(slab_folio(slab))) {
1566		/*
1567		 * If this is a slab page then lets do the best we can
1568		 * to avoid issues in the future. Marking all objects
1569		 * as used avoids touching the remaining objects.
1570		 */
1571		slab_fix(s, "Marking all objects used");
1572		slab->inuse = slab->objects;
1573		slab->freelist = NULL;
1574	}
1575	return false;
1576}
1577
1578static inline int free_consistency_checks(struct kmem_cache *s,
1579		struct slab *slab, void *object, unsigned long addr)
1580{
1581	if (!check_valid_pointer(s, slab, object)) {
1582		slab_err(s, slab, "Invalid object pointer 0x%p", object);
1583		return 0;
1584	}
1585
1586	if (on_freelist(s, slab, object)) {
1587		object_err(s, slab, object, "Object already free");
1588		return 0;
1589	}
1590
1591	if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
1592		return 0;
1593
1594	if (unlikely(s != slab->slab_cache)) {
1595		if (!folio_test_slab(slab_folio(slab))) {
1596			slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
1597				 object);
1598		} else if (!slab->slab_cache) {
1599			pr_err("SLUB <none>: no slab for object 0x%p.\n",
1600			       object);
1601			dump_stack();
1602		} else
1603			object_err(s, slab, object,
1604					"page slab pointer corrupt.");
1605		return 0;
1606	}
1607	return 1;
1608}
1609
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1610/*
1611 * Parse a block of slab_debug options. Blocks are delimited by ';'
1612 *
1613 * @str:    start of block
1614 * @flags:  returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
1615 * @slabs:  return start of list of slabs, or NULL when there's no list
1616 * @init:   assume this is initial parsing and not per-kmem-create parsing
1617 *
1618 * returns the start of next block if there's any, or NULL
1619 */
1620static char *
1621parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
1622{
1623	bool higher_order_disable = false;
1624
1625	/* Skip any completely empty blocks */
1626	while (*str && *str == ';')
1627		str++;
1628
1629	if (*str == ',') {
1630		/*
1631		 * No options but restriction on slabs. This means full
1632		 * debugging for slabs matching a pattern.
1633		 */
1634		*flags = DEBUG_DEFAULT_FLAGS;
1635		goto check_slabs;
1636	}
1637	*flags = 0;
1638
1639	/* Determine which debug features should be switched on */
1640	for (; *str && *str != ',' && *str != ';'; str++) {
1641		switch (tolower(*str)) {
1642		case '-':
1643			*flags = 0;
1644			break;
1645		case 'f':
1646			*flags |= SLAB_CONSISTENCY_CHECKS;
1647			break;
1648		case 'z':
1649			*flags |= SLAB_RED_ZONE;
1650			break;
1651		case 'p':
1652			*flags |= SLAB_POISON;
1653			break;
1654		case 'u':
1655			*flags |= SLAB_STORE_USER;
1656			break;
1657		case 't':
1658			*flags |= SLAB_TRACE;
1659			break;
1660		case 'a':
1661			*flags |= SLAB_FAILSLAB;
1662			break;
1663		case 'o':
1664			/*
1665			 * Avoid enabling debugging on caches if its minimum
1666			 * order would increase as a result.
1667			 */
1668			higher_order_disable = true;
1669			break;
1670		default:
1671			if (init)
1672				pr_err("slab_debug option '%c' unknown. skipped\n", *str);
1673		}
1674	}
1675check_slabs:
1676	if (*str == ',')
1677		*slabs = ++str;
1678	else
1679		*slabs = NULL;
1680
1681	/* Skip over the slab list */
1682	while (*str && *str != ';')
1683		str++;
1684
1685	/* Skip any completely empty blocks */
1686	while (*str && *str == ';')
1687		str++;
1688
1689	if (init && higher_order_disable)
1690		disable_higher_order_debug = 1;
1691
1692	if (*str)
1693		return str;
1694	else
1695		return NULL;
1696}
1697
1698static int __init setup_slub_debug(char *str)
1699{
1700	slab_flags_t flags;
1701	slab_flags_t global_flags;
1702	char *saved_str;
1703	char *slab_list;
1704	bool global_slub_debug_changed = false;
1705	bool slab_list_specified = false;
1706
1707	global_flags = DEBUG_DEFAULT_FLAGS;
1708	if (*str++ != '=' || !*str)
1709		/*
1710		 * No options specified. Switch on full debugging.
1711		 */
1712		goto out;
1713
1714	saved_str = str;
1715	while (str) {
1716		str = parse_slub_debug_flags(str, &flags, &slab_list, true);
1717
1718		if (!slab_list) {
1719			global_flags = flags;
1720			global_slub_debug_changed = true;
1721		} else {
1722			slab_list_specified = true;
1723			if (flags & SLAB_STORE_USER)
1724				stack_depot_request_early_init();
1725		}
1726	}
1727
1728	/*
1729	 * For backwards compatibility, a single list of flags with list of
1730	 * slabs means debugging is only changed for those slabs, so the global
1731	 * slab_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
1732	 * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
1733	 * long as there is no option specifying flags without a slab list.
1734	 */
1735	if (slab_list_specified) {
1736		if (!global_slub_debug_changed)
1737			global_flags = slub_debug;
1738		slub_debug_string = saved_str;
1739	}
1740out:
1741	slub_debug = global_flags;
1742	if (slub_debug & SLAB_STORE_USER)
1743		stack_depot_request_early_init();
1744	if (slub_debug != 0 || slub_debug_string)
1745		static_branch_enable(&slub_debug_enabled);
1746	else
1747		static_branch_disable(&slub_debug_enabled);
1748	if ((static_branch_unlikely(&init_on_alloc) ||
1749	     static_branch_unlikely(&init_on_free)) &&
1750	    (slub_debug & SLAB_POISON))
1751		pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
1752	return 1;
1753}
1754
1755__setup("slab_debug", setup_slub_debug);
1756__setup_param("slub_debug", slub_debug, setup_slub_debug, 0);
1757
1758/*
1759 * kmem_cache_flags - apply debugging options to the cache
 
1760 * @flags:		flags to set
1761 * @name:		name of the cache
1762 *
1763 * Debug option(s) are applied to @flags. In addition to the debug
1764 * option(s), if a slab name (or multiple) is specified i.e.
1765 * slab_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1766 * then only the select slabs will receive the debug option(s).
1767 */
1768slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name)
 
1769{
1770	char *iter;
1771	size_t len;
1772	char *next_block;
1773	slab_flags_t block_flags;
1774	slab_flags_t slub_debug_local = slub_debug;
1775
1776	if (flags & SLAB_NO_USER_FLAGS)
1777		return flags;
1778
1779	/*
1780	 * If the slab cache is for debugging (e.g. kmemleak) then
1781	 * don't store user (stack trace) information by default,
1782	 * but let the user enable it via the command line below.
1783	 */
1784	if (flags & SLAB_NOLEAKTRACE)
1785		slub_debug_local &= ~SLAB_STORE_USER;
1786
1787	len = strlen(name);
1788	next_block = slub_debug_string;
1789	/* Go through all blocks of debug options, see if any matches our slab's name */
1790	while (next_block) {
1791		next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
1792		if (!iter)
1793			continue;
1794		/* Found a block that has a slab list, search it */
1795		while (*iter) {
1796			char *end, *glob;
1797			size_t cmplen;
1798
1799			end = strchrnul(iter, ',');
1800			if (next_block && next_block < end)
1801				end = next_block - 1;
1802
1803			glob = strnchr(iter, end - iter, '*');
1804			if (glob)
1805				cmplen = glob - iter;
1806			else
1807				cmplen = max_t(size_t, len, (end - iter));
1808
1809			if (!strncmp(name, iter, cmplen)) {
1810				flags |= block_flags;
1811				return flags;
1812			}
1813
1814			if (!*end || *end == ';')
1815				break;
1816			iter = end + 1;
1817		}
1818	}
1819
1820	return flags | slub_debug_local;
1821}
1822#else /* !CONFIG_SLUB_DEBUG */
1823static inline void setup_object_debug(struct kmem_cache *s, void *object) {}
 
1824static inline
1825void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
1826
1827static inline bool alloc_debug_processing(struct kmem_cache *s,
1828	struct slab *slab, void *object, int orig_size) { return true; }
1829
1830static inline bool free_debug_processing(struct kmem_cache *s,
1831	struct slab *slab, void *head, void *tail, int *bulk_cnt,
1832	unsigned long addr, depot_stack_handle_t handle) { return true; }
 
1833
1834static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {}
1835static inline int check_object(struct kmem_cache *s, struct slab *slab,
 
1836			void *object, u8 val) { return 1; }
1837static inline depot_stack_handle_t set_track_prepare(void) { return 0; }
1838static inline void set_track(struct kmem_cache *s, void *object,
1839			     enum track_item alloc, unsigned long addr) {}
1840static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1841					struct slab *slab) {}
1842static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1843					struct slab *slab) {}
1844slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name)
 
1845{
1846	return flags;
1847}
1848#define slub_debug 0
1849
1850#define disable_higher_order_debug 0
1851
 
 
1852static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1853							{ return 0; }
1854static inline void inc_slabs_node(struct kmem_cache *s, int node,
1855							int objects) {}
1856static inline void dec_slabs_node(struct kmem_cache *s, int node,
1857							int objects) {}
1858
1859#ifndef CONFIG_SLUB_TINY
1860static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
1861			       void **freelist, void *nextfree)
1862{
1863	return false;
1864}
1865#endif
1866#endif /* CONFIG_SLUB_DEBUG */
1867
1868static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
1869{
1870	return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1871		NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
1872}
1873
1874#ifdef CONFIG_MEMCG_KMEM
1875static inline void memcg_free_slab_cgroups(struct slab *slab)
1876{
1877	kfree(slab_objcgs(slab));
1878	slab->memcg_data = 0;
1879}
1880
1881static inline size_t obj_full_size(struct kmem_cache *s)
1882{
1883	/*
1884	 * For each accounted object there is an extra space which is used
1885	 * to store obj_cgroup membership. Charge it too.
1886	 */
1887	return s->size + sizeof(struct obj_cgroup *);
1888}
1889
1890/*
1891 * Returns false if the allocation should fail.
1892 */
1893static bool __memcg_slab_pre_alloc_hook(struct kmem_cache *s,
1894					struct list_lru *lru,
1895					struct obj_cgroup **objcgp,
1896					size_t objects, gfp_t flags)
1897{
1898	/*
1899	 * The obtained objcg pointer is safe to use within the current scope,
1900	 * defined by current task or set_active_memcg() pair.
1901	 * obj_cgroup_get() is used to get a permanent reference.
1902	 */
1903	struct obj_cgroup *objcg = current_obj_cgroup();
1904	if (!objcg)
1905		return true;
1906
1907	if (lru) {
1908		int ret;
1909		struct mem_cgroup *memcg;
1910
1911		memcg = get_mem_cgroup_from_objcg(objcg);
1912		ret = memcg_list_lru_alloc(memcg, lru, flags);
1913		css_put(&memcg->css);
1914
1915		if (ret)
1916			return false;
1917	}
1918
1919	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s)))
1920		return false;
1921
1922	*objcgp = objcg;
1923	return true;
1924}
1925
1926/*
1927 * Returns false if the allocation should fail.
 
1928 */
1929static __fastpath_inline
1930bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
1931			       struct obj_cgroup **objcgp, size_t objects,
1932			       gfp_t flags)
1933{
1934	if (!memcg_kmem_online())
1935		return true;
1936
1937	if (likely(!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT)))
1938		return true;
1939
1940	return likely(__memcg_slab_pre_alloc_hook(s, lru, objcgp, objects,
1941						  flags));
1942}
1943
1944static void __memcg_slab_post_alloc_hook(struct kmem_cache *s,
1945					 struct obj_cgroup *objcg,
1946					 gfp_t flags, size_t size,
1947					 void **p)
1948{
1949	struct slab *slab;
1950	unsigned long off;
1951	size_t i;
1952
1953	flags &= gfp_allowed_mask;
1954
1955	for (i = 0; i < size; i++) {
1956		if (likely(p[i])) {
1957			slab = virt_to_slab(p[i]);
1958
1959			if (!slab_objcgs(slab) &&
1960			    memcg_alloc_slab_cgroups(slab, s, flags, false)) {
1961				obj_cgroup_uncharge(objcg, obj_full_size(s));
1962				continue;
1963			}
1964
1965			off = obj_to_index(s, slab, p[i]);
1966			obj_cgroup_get(objcg);
1967			slab_objcgs(slab)[off] = objcg;
1968			mod_objcg_state(objcg, slab_pgdat(slab),
1969					cache_vmstat_idx(s), obj_full_size(s));
1970		} else {
1971			obj_cgroup_uncharge(objcg, obj_full_size(s));
1972		}
1973	}
1974}
1975
1976static __fastpath_inline
1977void memcg_slab_post_alloc_hook(struct kmem_cache *s, struct obj_cgroup *objcg,
1978				gfp_t flags, size_t size, void **p)
1979{
1980	if (likely(!memcg_kmem_online() || !objcg))
1981		return;
1982
1983	return __memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
1984}
1985
1986static void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
1987				   void **p, int objects,
1988				   struct obj_cgroup **objcgs)
1989{
1990	for (int i = 0; i < objects; i++) {
1991		struct obj_cgroup *objcg;
1992		unsigned int off;
1993
1994		off = obj_to_index(s, slab, p[i]);
1995		objcg = objcgs[off];
1996		if (!objcg)
1997			continue;
1998
1999		objcgs[off] = NULL;
2000		obj_cgroup_uncharge(objcg, obj_full_size(s));
2001		mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s),
2002				-obj_full_size(s));
2003		obj_cgroup_put(objcg);
2004	}
2005}
2006
2007static __fastpath_inline
2008void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p,
2009			  int objects)
2010{
2011	struct obj_cgroup **objcgs;
2012
2013	if (!memcg_kmem_online())
2014		return;
2015
2016	objcgs = slab_objcgs(slab);
2017	if (likely(!objcgs))
2018		return;
2019
2020	__memcg_slab_free_hook(s, slab, p, objects, objcgs);
2021}
2022
2023static inline
2024void memcg_slab_alloc_error_hook(struct kmem_cache *s, int objects,
2025			   struct obj_cgroup *objcg)
2026{
2027	if (objcg)
2028		obj_cgroup_uncharge(objcg, objects * obj_full_size(s));
2029}
2030#else /* CONFIG_MEMCG_KMEM */
2031static inline void memcg_free_slab_cgroups(struct slab *slab)
2032{
2033}
2034
2035static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
2036					     struct list_lru *lru,
2037					     struct obj_cgroup **objcgp,
2038					     size_t objects, gfp_t flags)
2039{
2040	return true;
2041}
2042
2043static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
2044					      struct obj_cgroup *objcg,
2045					      gfp_t flags, size_t size,
2046					      void **p)
2047{
 
 
 
 
2048}
2049
2050static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
2051					void **p, int objects)
2052{
 
 
2053}
2054
2055static inline
2056void memcg_slab_alloc_error_hook(struct kmem_cache *s, int objects,
2057				 struct obj_cgroup *objcg)
2058{
2059}
2060#endif /* CONFIG_MEMCG_KMEM */
2061
2062/*
2063 * Hooks for other subsystems that check memory allocations. In a typical
2064 * production configuration these hooks all should produce no code at all.
2065 *
2066 * Returns true if freeing of the object can proceed, false if its reuse
2067 * was delayed by KASAN quarantine, or it was returned to KFENCE.
2068 */
2069static __always_inline
2070bool slab_free_hook(struct kmem_cache *s, void *x, bool init)
2071{
2072	kmemleak_free_recursive(x, s->flags);
2073	kmsan_slab_free(s, x);
2074
2075	debug_check_no_locks_freed(x, s->object_size);
 
 
 
 
 
 
 
2076
 
 
 
 
 
2077	if (!(s->flags & SLAB_DEBUG_OBJECTS))
2078		debug_check_no_obj_freed(x, s->object_size);
2079
2080	/* Use KCSAN to help debug racy use-after-free. */
2081	if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
2082		__kcsan_check_access(x, s->object_size,
2083				     KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
2084
2085	if (kfence_free(x))
2086		return false;
2087
2088	/*
2089	 * As memory initialization might be integrated into KASAN,
2090	 * kasan_slab_free and initialization memset's must be
2091	 * kept together to avoid discrepancies in behavior.
2092	 *
2093	 * The initialization memset's clear the object and the metadata,
2094	 * but don't touch the SLAB redzone.
2095	 *
2096	 * The object's freepointer is also avoided if stored outside the
2097	 * object.
2098	 */
2099	if (unlikely(init)) {
2100		int rsize;
2101		unsigned int inuse;
2102
2103		inuse = get_info_end(s);
2104		if (!kasan_has_integrated_init())
2105			memset(kasan_reset_tag(x), 0, s->object_size);
2106		rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
2107		memset((char *)kasan_reset_tag(x) + inuse, 0,
2108		       s->size - inuse - rsize);
2109	}
2110	/* KASAN might put x into memory quarantine, delaying its reuse. */
2111	return !kasan_slab_free(s, x, init);
2112}
2113
2114static inline bool slab_free_freelist_hook(struct kmem_cache *s,
2115					   void **head, void **tail,
2116					   int *cnt)
2117{
2118
2119	void *object;
2120	void *next = *head;
2121	void *old_tail = *tail;
2122	bool init;
2123
2124	if (is_kfence_address(next)) {
2125		slab_free_hook(s, next, false);
2126		return false;
2127	}
2128
2129	/* Head and tail of the reconstructed freelist */
2130	*head = NULL;
2131	*tail = NULL;
2132
2133	init = slab_want_init_on_free(s);
2134
2135	do {
2136		object = next;
2137		next = get_freepointer(s, object);
2138
2139		/* If object's reuse doesn't have to be delayed */
2140		if (likely(slab_free_hook(s, object, init))) {
2141			/* Move object to the new freelist */
2142			set_freepointer(s, object, *head);
2143			*head = object;
2144			if (!*tail)
2145				*tail = object;
2146		} else {
2147			/*
2148			 * Adjust the reconstructed freelist depth
2149			 * accordingly if object's reuse is delayed.
2150			 */
2151			--(*cnt);
2152		}
2153	} while (object != old_tail);
2154
 
 
 
2155	return *head != NULL;
2156}
2157
2158static void *setup_object(struct kmem_cache *s, void *object)
 
2159{
2160	setup_object_debug(s, object);
2161	object = kasan_init_slab_obj(s, object);
2162	if (unlikely(s->ctor)) {
2163		kasan_unpoison_new_object(s, object);
2164		s->ctor(object);
2165		kasan_poison_new_object(s, object);
2166	}
2167	return object;
2168}
2169
2170/*
2171 * Slab allocation and freeing
2172 */
2173static inline struct slab *alloc_slab_page(gfp_t flags, int node,
2174		struct kmem_cache_order_objects oo)
2175{
2176	struct folio *folio;
2177	struct slab *slab;
2178	unsigned int order = oo_order(oo);
2179
2180	folio = (struct folio *)alloc_pages_node(node, flags, order);
2181	if (!folio)
2182		return NULL;
2183
2184	slab = folio_slab(folio);
2185	__folio_set_slab(folio);
2186	/* Make the flag visible before any changes to folio->mapping */
2187	smp_wmb();
2188	if (folio_is_pfmemalloc(folio))
2189		slab_set_pfmemalloc(slab);
2190
2191	return slab;
2192}
2193
2194#ifdef CONFIG_SLAB_FREELIST_RANDOM
2195/* Pre-initialize the random sequence cache */
2196static int init_cache_random_seq(struct kmem_cache *s)
2197{
2198	unsigned int count = oo_objects(s->oo);
2199	int err;
2200
2201	/* Bailout if already initialised */
2202	if (s->random_seq)
2203		return 0;
2204
2205	err = cache_random_seq_create(s, count, GFP_KERNEL);
2206	if (err) {
2207		pr_err("SLUB: Unable to initialize free list for %s\n",
2208			s->name);
2209		return err;
2210	}
2211
2212	/* Transform to an offset on the set of pages */
2213	if (s->random_seq) {
2214		unsigned int i;
2215
2216		for (i = 0; i < count; i++)
2217			s->random_seq[i] *= s->size;
2218	}
2219	return 0;
2220}
2221
2222/* Initialize each random sequence freelist per cache */
2223static void __init init_freelist_randomization(void)
2224{
2225	struct kmem_cache *s;
2226
2227	mutex_lock(&slab_mutex);
2228
2229	list_for_each_entry(s, &slab_caches, list)
2230		init_cache_random_seq(s);
2231
2232	mutex_unlock(&slab_mutex);
2233}
2234
2235/* Get the next entry on the pre-computed freelist randomized */
2236static void *next_freelist_entry(struct kmem_cache *s,
2237				unsigned long *pos, void *start,
2238				unsigned long page_limit,
2239				unsigned long freelist_count)
2240{
2241	unsigned int idx;
2242
2243	/*
2244	 * If the target page allocation failed, the number of objects on the
2245	 * page might be smaller than the usual size defined by the cache.
2246	 */
2247	do {
2248		idx = s->random_seq[*pos];
2249		*pos += 1;
2250		if (*pos >= freelist_count)
2251			*pos = 0;
2252	} while (unlikely(idx >= page_limit));
2253
2254	return (char *)start + idx;
2255}
2256
2257/* Shuffle the single linked freelist based on a random pre-computed sequence */
2258static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
2259{
2260	void *start;
2261	void *cur;
2262	void *next;
2263	unsigned long idx, pos, page_limit, freelist_count;
2264
2265	if (slab->objects < 2 || !s->random_seq)
2266		return false;
2267
2268	freelist_count = oo_objects(s->oo);
2269	pos = get_random_u32_below(freelist_count);
2270
2271	page_limit = slab->objects * s->size;
2272	start = fixup_red_left(s, slab_address(slab));
2273
2274	/* First entry is used as the base of the freelist */
2275	cur = next_freelist_entry(s, &pos, start, page_limit, freelist_count);
2276	cur = setup_object(s, cur);
2277	slab->freelist = cur;
 
2278
2279	for (idx = 1; idx < slab->objects; idx++) {
2280		next = next_freelist_entry(s, &pos, start, page_limit,
2281			freelist_count);
2282		next = setup_object(s, next);
2283		set_freepointer(s, cur, next);
2284		cur = next;
2285	}
2286	set_freepointer(s, cur, NULL);
2287
2288	return true;
2289}
2290#else
2291static inline int init_cache_random_seq(struct kmem_cache *s)
2292{
2293	return 0;
2294}
2295static inline void init_freelist_randomization(void) { }
2296static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
2297{
2298	return false;
2299}
2300#endif /* CONFIG_SLAB_FREELIST_RANDOM */
2301
2302static __always_inline void account_slab(struct slab *slab, int order,
2303					 struct kmem_cache *s, gfp_t gfp)
2304{
2305	if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT))
2306		memcg_alloc_slab_cgroups(slab, s, gfp, true);
2307
2308	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
2309			    PAGE_SIZE << order);
2310}
2311
2312static __always_inline void unaccount_slab(struct slab *slab, int order,
2313					   struct kmem_cache *s)
2314{
2315	if (memcg_kmem_online())
2316		memcg_free_slab_cgroups(slab);
2317
2318	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
2319			    -(PAGE_SIZE << order));
2320}
2321
2322static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
2323{
2324	struct slab *slab;
2325	struct kmem_cache_order_objects oo = s->oo;
2326	gfp_t alloc_gfp;
2327	void *start, *p, *next;
2328	int idx;
2329	bool shuffle;
2330
2331	flags &= gfp_allowed_mask;
2332
 
 
 
2333	flags |= s->allocflags;
2334
2335	/*
2336	 * Let the initial higher-order allocation fail under memory pressure
2337	 * so we fall-back to the minimum order allocation.
2338	 */
2339	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
2340	if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
2341		alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
2342
2343	slab = alloc_slab_page(alloc_gfp, node, oo);
2344	if (unlikely(!slab)) {
2345		oo = s->min;
2346		alloc_gfp = flags;
2347		/*
2348		 * Allocation may have failed due to fragmentation.
2349		 * Try a lower order alloc if possible
2350		 */
2351		slab = alloc_slab_page(alloc_gfp, node, oo);
2352		if (unlikely(!slab))
2353			return NULL;
2354		stat(s, ORDER_FALLBACK);
2355	}
2356
2357	slab->objects = oo_objects(oo);
2358	slab->inuse = 0;
2359	slab->frozen = 0;
2360
2361	account_slab(slab, oo_order(oo), s, flags);
2362
2363	slab->slab_cache = s;
 
 
 
2364
2365	kasan_poison_slab(slab);
2366
2367	start = slab_address(slab);
2368
2369	setup_slab_debug(s, slab, start);
2370
2371	shuffle = shuffle_freelist(s, slab);
2372
2373	if (!shuffle) {
2374		start = fixup_red_left(s, start);
2375		start = setup_object(s, start);
2376		slab->freelist = start;
2377		for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
2378			next = p + s->size;
2379			next = setup_object(s, next);
2380			set_freepointer(s, p, next);
2381			p = next;
2382		}
2383		set_freepointer(s, p, NULL);
2384	}
2385
2386	return slab;
 
 
 
 
 
 
 
 
 
 
 
2387}
2388
2389static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
2390{
2391	if (unlikely(flags & GFP_SLAB_BUG_MASK))
2392		flags = kmalloc_fix_flags(flags);
2393
2394	WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2395
2396	return allocate_slab(s,
2397		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
2398}
2399
2400static void __free_slab(struct kmem_cache *s, struct slab *slab)
2401{
2402	struct folio *folio = slab_folio(slab);
2403	int order = folio_order(folio);
2404	int pages = 1 << order;
2405
2406	__slab_clear_pfmemalloc(slab);
2407	folio->mapping = NULL;
2408	/* Make the mapping reset visible before clearing the flag */
2409	smp_wmb();
2410	__folio_clear_slab(folio);
2411	mm_account_reclaimed_pages(pages);
2412	unaccount_slab(slab, order, s);
2413	__free_pages(&folio->page, order);
2414}
2415
2416static void rcu_free_slab(struct rcu_head *h)
2417{
2418	struct slab *slab = container_of(h, struct slab, rcu_head);
2419
2420	__free_slab(slab->slab_cache, slab);
2421}
2422
2423static void free_slab(struct kmem_cache *s, struct slab *slab)
2424{
2425	if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
2426		void *p;
2427
2428		slab_pad_check(s, slab);
2429		for_each_object(p, s, slab_address(slab), slab->objects)
2430			check_object(s, slab, p, SLUB_RED_INACTIVE);
 
2431	}
2432
2433	if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU))
2434		call_rcu(&slab->rcu_head, rcu_free_slab);
2435	else
2436		__free_slab(s, slab);
 
 
 
 
2437}
2438
2439static void discard_slab(struct kmem_cache *s, struct slab *slab)
2440{
2441	dec_slabs_node(s, slab_nid(slab), slab->objects);
2442	free_slab(s, slab);
2443}
2444
2445/*
2446 * SLUB reuses PG_workingset bit to keep track of whether it's on
2447 * the per-node partial list.
2448 */
2449static inline bool slab_test_node_partial(const struct slab *slab)
2450{
2451	return folio_test_workingset((struct folio *)slab_folio(slab));
2452}
2453
2454static inline void slab_set_node_partial(struct slab *slab)
2455{
2456	set_bit(PG_workingset, folio_flags(slab_folio(slab), 0));
 
 
 
2457}
2458
2459static inline void slab_clear_node_partial(struct slab *slab)
2460{
2461	clear_bit(PG_workingset, folio_flags(slab_folio(slab), 0));
 
2462}
2463
2464/*
2465 * Management of partially allocated slabs.
2466 */
2467static inline void
2468__add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
2469{
2470	n->nr_partial++;
2471	if (tail == DEACTIVATE_TO_TAIL)
2472		list_add_tail(&slab->slab_list, &n->partial);
2473	else
2474		list_add(&slab->slab_list, &n->partial);
2475	slab_set_node_partial(slab);
2476}
2477
2478static inline void add_partial(struct kmem_cache_node *n,
2479				struct slab *slab, int tail)
2480{
2481	lockdep_assert_held(&n->list_lock);
2482	__add_partial(n, slab, tail);
2483}
2484
2485static inline void remove_partial(struct kmem_cache_node *n,
2486					struct slab *slab)
2487{
2488	lockdep_assert_held(&n->list_lock);
2489	list_del(&slab->slab_list);
2490	slab_clear_node_partial(slab);
2491	n->nr_partial--;
2492}
2493
2494/*
2495 * Called only for kmem_cache_debug() caches instead of remove_partial(), with a
2496 * slab from the n->partial list. Remove only a single object from the slab, do
2497 * the alloc_debug_processing() checks and leave the slab on the list, or move
2498 * it to full list if it was the last free object.
2499 */
2500static void *alloc_single_from_partial(struct kmem_cache *s,
2501		struct kmem_cache_node *n, struct slab *slab, int orig_size)
 
2502{
2503	void *object;
 
 
2504
2505	lockdep_assert_held(&n->list_lock);
2506
2507	object = slab->freelist;
2508	slab->freelist = get_freepointer(s, object);
2509	slab->inuse++;
2510
2511	if (!alloc_debug_processing(s, slab, object, orig_size)) {
2512		remove_partial(n, slab);
2513		return NULL;
2514	}
2515
2516	if (slab->inuse == slab->objects) {
2517		remove_partial(n, slab);
2518		add_full(s, n, slab);
 
 
2519	}
2520
2521	return object;
2522}
2523
2524/*
2525 * Called only for kmem_cache_debug() caches to allocate from a freshly
2526 * allocated slab. Allocate a single object instead of whole freelist
2527 * and put the slab to the partial (or full) list.
2528 */
2529static void *alloc_single_from_new_slab(struct kmem_cache *s,
2530					struct slab *slab, int orig_size)
2531{
2532	int nid = slab_nid(slab);
2533	struct kmem_cache_node *n = get_node(s, nid);
2534	unsigned long flags;
2535	void *object;
2536
2537
2538	object = slab->freelist;
2539	slab->freelist = get_freepointer(s, object);
2540	slab->inuse = 1;
2541
2542	if (!alloc_debug_processing(s, slab, object, orig_size))
2543		/*
2544		 * It's not really expected that this would fail on a
2545		 * freshly allocated slab, but a concurrent memory
2546		 * corruption in theory could cause that.
2547		 */
2548		return NULL;
2549
2550	spin_lock_irqsave(&n->list_lock, flags);
2551
2552	if (slab->inuse == slab->objects)
2553		add_full(s, n, slab);
2554	else
2555		add_partial(n, slab, DEACTIVATE_TO_HEAD);
2556
2557	inc_slabs_node(s, nid, slab->objects);
2558	spin_unlock_irqrestore(&n->list_lock, flags);
2559
2560	return object;
2561}
2562
2563#ifdef CONFIG_SLUB_CPU_PARTIAL
2564static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
2565#else
2566static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
2567				   int drain) { }
2568#endif
2569static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
2570
2571/*
2572 * Try to allocate a partial slab from a specific node.
2573 */
2574static struct slab *get_partial_node(struct kmem_cache *s,
2575				     struct kmem_cache_node *n,
2576				     struct partial_context *pc)
2577{
2578	struct slab *slab, *slab2, *partial = NULL;
2579	unsigned long flags;
2580	unsigned int partial_slabs = 0;
 
2581
2582	/*
2583	 * Racy check. If we mistakenly see no partial slabs then we
2584	 * just allocate an empty slab. If we mistakenly try to get a
2585	 * partial slab and there is none available then get_partial()
2586	 * will return NULL.
2587	 */
2588	if (!n || !n->nr_partial)
2589		return NULL;
2590
2591	spin_lock_irqsave(&n->list_lock, flags);
2592	list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
2593		if (!pfmemalloc_match(slab, pc->flags))
2594			continue;
2595
2596		if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
2597			void *object = alloc_single_from_partial(s, n, slab,
2598							pc->orig_size);
2599			if (object) {
2600				partial = slab;
2601				pc->object = object;
2602				break;
2603			}
2604			continue;
2605		}
2606
2607		remove_partial(n, slab);
 
 
2608
2609		if (!partial) {
2610			partial = slab;
 
2611			stat(s, ALLOC_FROM_PARTIAL);
 
2612		} else {
2613			put_cpu_partial(s, slab, 0);
2614			stat(s, CPU_PARTIAL_NODE);
2615			partial_slabs++;
2616		}
2617#ifdef CONFIG_SLUB_CPU_PARTIAL
2618		if (!kmem_cache_has_cpu_partial(s)
2619			|| partial_slabs > s->cpu_partial_slabs / 2)
2620			break;
2621#else
2622		break;
2623#endif
2624
2625	}
2626	spin_unlock_irqrestore(&n->list_lock, flags);
2627	return partial;
2628}
2629
2630/*
2631 * Get a slab from somewhere. Search in increasing NUMA distances.
2632 */
2633static struct slab *get_any_partial(struct kmem_cache *s,
2634				    struct partial_context *pc)
2635{
2636#ifdef CONFIG_NUMA
2637	struct zonelist *zonelist;
2638	struct zoneref *z;
2639	struct zone *zone;
2640	enum zone_type highest_zoneidx = gfp_zone(pc->flags);
2641	struct slab *slab;
2642	unsigned int cpuset_mems_cookie;
2643
2644	/*
2645	 * The defrag ratio allows a configuration of the tradeoffs between
2646	 * inter node defragmentation and node local allocations. A lower
2647	 * defrag_ratio increases the tendency to do local allocations
2648	 * instead of attempting to obtain partial slabs from other nodes.
2649	 *
2650	 * If the defrag_ratio is set to 0 then kmalloc() always
2651	 * returns node local objects. If the ratio is higher then kmalloc()
2652	 * may return off node objects because partial slabs are obtained
2653	 * from other nodes and filled up.
2654	 *
2655	 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
2656	 * (which makes defrag_ratio = 1000) then every (well almost)
2657	 * allocation will first attempt to defrag slab caches on other nodes.
2658	 * This means scanning over all nodes to look for partial slabs which
2659	 * may be expensive if we do it every time we are trying to find a slab
2660	 * with available objects.
2661	 */
2662	if (!s->remote_node_defrag_ratio ||
2663			get_cycles() % 1024 > s->remote_node_defrag_ratio)
2664		return NULL;
2665
2666	do {
2667		cpuset_mems_cookie = read_mems_allowed_begin();
2668		zonelist = node_zonelist(mempolicy_slab_node(), pc->flags);
2669		for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
2670			struct kmem_cache_node *n;
2671
2672			n = get_node(s, zone_to_nid(zone));
2673
2674			if (n && cpuset_zone_allowed(zone, pc->flags) &&
2675					n->nr_partial > s->min_partial) {
2676				slab = get_partial_node(s, n, pc);
2677				if (slab) {
2678					/*
2679					 * Don't check read_mems_allowed_retry()
2680					 * here - if mems_allowed was updated in
2681					 * parallel, that was a harmless race
2682					 * between allocation and the cpuset
2683					 * update
2684					 */
2685					return slab;
2686				}
2687			}
2688		}
2689	} while (read_mems_allowed_retry(cpuset_mems_cookie));
2690#endif	/* CONFIG_NUMA */
2691	return NULL;
2692}
2693
2694/*
2695 * Get a partial slab, lock it and return it.
2696 */
2697static struct slab *get_partial(struct kmem_cache *s, int node,
2698				struct partial_context *pc)
2699{
2700	struct slab *slab;
2701	int searchnode = node;
2702
2703	if (node == NUMA_NO_NODE)
2704		searchnode = numa_mem_id();
2705
2706	slab = get_partial_node(s, get_node(s, searchnode), pc);
2707	if (slab || node != NUMA_NO_NODE)
2708		return slab;
2709
2710	return get_any_partial(s, pc);
2711}
2712
2713#ifndef CONFIG_SLUB_TINY
2714
2715#ifdef CONFIG_PREEMPTION
2716/*
2717 * Calculate the next globally unique transaction for disambiguation
2718 * during cmpxchg. The transactions start with the cpu number and are then
2719 * incremented by CONFIG_NR_CPUS.
2720 */
2721#define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
2722#else
2723/*
2724 * No preemption supported therefore also no need to check for
2725 * different cpus.
2726 */
2727#define TID_STEP 1
2728#endif /* CONFIG_PREEMPTION */
2729
2730static inline unsigned long next_tid(unsigned long tid)
2731{
2732	return tid + TID_STEP;
2733}
2734
2735#ifdef SLUB_DEBUG_CMPXCHG
2736static inline unsigned int tid_to_cpu(unsigned long tid)
2737{
2738	return tid % TID_STEP;
2739}
2740
2741static inline unsigned long tid_to_event(unsigned long tid)
2742{
2743	return tid / TID_STEP;
2744}
2745#endif
2746
2747static inline unsigned int init_tid(int cpu)
2748{
2749	return cpu;
2750}
2751
2752static inline void note_cmpxchg_failure(const char *n,
2753		const struct kmem_cache *s, unsigned long tid)
2754{
2755#ifdef SLUB_DEBUG_CMPXCHG
2756	unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2757
2758	pr_info("%s %s: cmpxchg redo ", n, s->name);
2759
2760#ifdef CONFIG_PREEMPTION
2761	if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2762		pr_warn("due to cpu change %d -> %d\n",
2763			tid_to_cpu(tid), tid_to_cpu(actual_tid));
2764	else
2765#endif
2766	if (tid_to_event(tid) != tid_to_event(actual_tid))
2767		pr_warn("due to cpu running other code. Event %ld->%ld\n",
2768			tid_to_event(tid), tid_to_event(actual_tid));
2769	else
2770		pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2771			actual_tid, tid, next_tid(tid));
2772#endif
2773	stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2774}
2775
2776static void init_kmem_cache_cpus(struct kmem_cache *s)
2777{
2778	int cpu;
2779	struct kmem_cache_cpu *c;
2780
2781	for_each_possible_cpu(cpu) {
2782		c = per_cpu_ptr(s->cpu_slab, cpu);
2783		local_lock_init(&c->lock);
2784		c->tid = init_tid(cpu);
2785	}
2786}
2787
2788/*
2789 * Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
2790 * unfreezes the slabs and puts it on the proper list.
2791 * Assumes the slab has been already safely taken away from kmem_cache_cpu
2792 * by the caller.
2793 */
2794static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
2795			    void *freelist)
2796{
2797	struct kmem_cache_node *n = get_node(s, slab_nid(slab));
2798	int free_delta = 0;
 
 
2799	void *nextfree, *freelist_iter, *freelist_tail;
2800	int tail = DEACTIVATE_TO_HEAD;
2801	unsigned long flags = 0;
2802	struct slab new;
2803	struct slab old;
2804
2805	if (slab->freelist) {
2806		stat(s, DEACTIVATE_REMOTE_FREES);
2807		tail = DEACTIVATE_TO_TAIL;
2808	}
2809
2810	/*
2811	 * Stage one: Count the objects on cpu's freelist as free_delta and
2812	 * remember the last object in freelist_tail for later splicing.
2813	 */
2814	freelist_tail = NULL;
2815	freelist_iter = freelist;
2816	while (freelist_iter) {
2817		nextfree = get_freepointer(s, freelist_iter);
2818
2819		/*
2820		 * If 'nextfree' is invalid, it is possible that the object at
2821		 * 'freelist_iter' is already corrupted.  So isolate all objects
2822		 * starting at 'freelist_iter' by skipping them.
2823		 */
2824		if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
2825			break;
2826
2827		freelist_tail = freelist_iter;
2828		free_delta++;
2829
2830		freelist_iter = nextfree;
2831	}
2832
2833	/*
2834	 * Stage two: Unfreeze the slab while splicing the per-cpu
2835	 * freelist to the head of slab's freelist.
 
 
 
 
 
 
 
 
 
 
 
 
2836	 */
2837	do {
2838		old.freelist = READ_ONCE(slab->freelist);
2839		old.counters = READ_ONCE(slab->counters);
2840		VM_BUG_ON(!old.frozen);
2841
2842		/* Determine target state of the slab */
2843		new.counters = old.counters;
2844		new.frozen = 0;
2845		if (freelist_tail) {
2846			new.inuse -= free_delta;
2847			set_freepointer(s, freelist_tail, old.freelist);
2848			new.freelist = freelist;
2849		} else {
2850			new.freelist = old.freelist;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2851		}
2852	} while (!slab_update_freelist(s, slab,
2853		old.freelist, old.counters,
2854		new.freelist, new.counters,
2855		"unfreezing slab"));
2856
2857	/*
2858	 * Stage three: Manipulate the slab list based on the updated state.
2859	 */
2860	if (!new.inuse && n->nr_partial >= s->min_partial) {
2861		stat(s, DEACTIVATE_EMPTY);
2862		discard_slab(s, slab);
2863		stat(s, FREE_SLAB);
2864	} else if (new.freelist) {
2865		spin_lock_irqsave(&n->list_lock, flags);
2866		add_partial(n, slab, tail);
2867		spin_unlock_irqrestore(&n->list_lock, flags);
 
 
 
 
 
 
 
 
 
 
 
 
2868		stat(s, tail);
2869	} else {
2870		stat(s, DEACTIVATE_FULL);
 
 
 
 
2871	}
 
 
 
2872}
2873
2874#ifdef CONFIG_SLUB_CPU_PARTIAL
2875static void __put_partials(struct kmem_cache *s, struct slab *partial_slab)
 
 
 
 
 
 
 
2876{
 
2877	struct kmem_cache_node *n = NULL, *n2 = NULL;
2878	struct slab *slab, *slab_to_discard = NULL;
2879	unsigned long flags = 0;
 
 
 
2880
2881	while (partial_slab) {
2882		slab = partial_slab;
2883		partial_slab = slab->next;
2884
2885		n2 = get_node(s, slab_nid(slab));
2886		if (n != n2) {
2887			if (n)
2888				spin_unlock_irqrestore(&n->list_lock, flags);
2889
2890			n = n2;
2891			spin_lock_irqsave(&n->list_lock, flags);
2892		}
2893
2894		if (unlikely(!slab->inuse && n->nr_partial >= s->min_partial)) {
2895			slab->next = slab_to_discard;
2896			slab_to_discard = slab;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2897		} else {
2898			add_partial(n, slab, DEACTIVATE_TO_TAIL);
2899			stat(s, FREE_ADD_PARTIAL);
2900		}
2901	}
2902
2903	if (n)
2904		spin_unlock_irqrestore(&n->list_lock, flags);
2905
2906	while (slab_to_discard) {
2907		slab = slab_to_discard;
2908		slab_to_discard = slab_to_discard->next;
2909
2910		stat(s, DEACTIVATE_EMPTY);
2911		discard_slab(s, slab);
2912		stat(s, FREE_SLAB);
2913	}
 
2914}
2915
2916/*
2917 * Put all the cpu partial slabs to the node partial list.
2918 */
2919static void put_partials(struct kmem_cache *s)
2920{
2921	struct slab *partial_slab;
2922	unsigned long flags;
2923
2924	local_lock_irqsave(&s->cpu_slab->lock, flags);
2925	partial_slab = this_cpu_read(s->cpu_slab->partial);
2926	this_cpu_write(s->cpu_slab->partial, NULL);
2927	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2928
2929	if (partial_slab)
2930		__put_partials(s, partial_slab);
2931}
2932
2933static void put_partials_cpu(struct kmem_cache *s,
2934			     struct kmem_cache_cpu *c)
2935{
2936	struct slab *partial_slab;
2937
2938	partial_slab = slub_percpu_partial(c);
2939	c->partial = NULL;
2940
2941	if (partial_slab)
2942		__put_partials(s, partial_slab);
2943}
2944
2945/*
2946 * Put a slab into a partial slab slot if available.
2947 *
2948 * If we did not find a slot then simply move all the partials to the
2949 * per node partial list.
2950 */
2951static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
2952{
2953	struct slab *oldslab;
2954	struct slab *slab_to_put = NULL;
2955	unsigned long flags;
2956	int slabs = 0;
2957
2958	local_lock_irqsave(&s->cpu_slab->lock, flags);
2959
2960	oldslab = this_cpu_read(s->cpu_slab->partial);
2961
2962	if (oldslab) {
2963		if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
2964			/*
2965			 * Partial array is full. Move the existing set to the
2966			 * per node partial list. Postpone the actual unfreezing
2967			 * outside of the critical section.
2968			 */
2969			slab_to_put = oldslab;
2970			oldslab = NULL;
2971		} else {
2972			slabs = oldslab->slabs;
 
 
 
 
 
 
 
 
 
 
 
 
2973		}
2974	}
2975
2976	slabs++;
2977
2978	slab->slabs = slabs;
2979	slab->next = oldslab;
2980
2981	this_cpu_write(s->cpu_slab->partial, slab);
2982
2983	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
 
 
 
 
2984
2985	if (slab_to_put) {
2986		__put_partials(s, slab_to_put);
2987		stat(s, CPU_PARTIAL_DRAIN);
2988	}
2989}
2990
2991#else	/* CONFIG_SLUB_CPU_PARTIAL */
2992
2993static inline void put_partials(struct kmem_cache *s) { }
2994static inline void put_partials_cpu(struct kmem_cache *s,
2995				    struct kmem_cache_cpu *c) { }
2996
2997#endif	/* CONFIG_SLUB_CPU_PARTIAL */
2998
2999static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
3000{
3001	unsigned long flags;
3002	struct slab *slab;
3003	void *freelist;
3004
3005	local_lock_irqsave(&s->cpu_slab->lock, flags);
3006
3007	slab = c->slab;
3008	freelist = c->freelist;
3009
3010	c->slab = NULL;
3011	c->freelist = NULL;
3012	c->tid = next_tid(c->tid);
3013
3014	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3015
3016	if (slab) {
3017		deactivate_slab(s, slab, freelist);
3018		stat(s, CPUSLAB_FLUSH);
3019	}
3020}
3021
3022static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
3023{
3024	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
3025	void *freelist = c->freelist;
3026	struct slab *slab = c->slab;
3027
3028	c->slab = NULL;
3029	c->freelist = NULL;
3030	c->tid = next_tid(c->tid);
3031
3032	if (slab) {
3033		deactivate_slab(s, slab, freelist);
3034		stat(s, CPUSLAB_FLUSH);
3035	}
3036
3037	put_partials_cpu(s, c);
3038}
3039
3040struct slub_flush_work {
3041	struct work_struct work;
3042	struct kmem_cache *s;
3043	bool skip;
3044};
3045
3046/*
3047 * Flush cpu slab.
3048 *
3049 * Called from CPU work handler with migration disabled.
3050 */
3051static void flush_cpu_slab(struct work_struct *w)
3052{
3053	struct kmem_cache *s;
3054	struct kmem_cache_cpu *c;
3055	struct slub_flush_work *sfw;
3056
3057	sfw = container_of(w, struct slub_flush_work, work);
3058
3059	s = sfw->s;
3060	c = this_cpu_ptr(s->cpu_slab);
3061
3062	if (c->slab)
3063		flush_slab(s, c);
3064
3065	put_partials(s);
3066}
3067
3068static bool has_cpu_slab(int cpu, struct kmem_cache *s)
3069{
3070	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
3071
3072	return c->slab || slub_percpu_partial(c);
3073}
3074
3075static DEFINE_MUTEX(flush_lock);
3076static DEFINE_PER_CPU(struct slub_flush_work, slub_flush);
3077
3078static void flush_all_cpus_locked(struct kmem_cache *s)
3079{
3080	struct slub_flush_work *sfw;
3081	unsigned int cpu;
3082
3083	lockdep_assert_cpus_held();
3084	mutex_lock(&flush_lock);
3085
3086	for_each_online_cpu(cpu) {
3087		sfw = &per_cpu(slub_flush, cpu);
3088		if (!has_cpu_slab(cpu, s)) {
3089			sfw->skip = true;
3090			continue;
3091		}
3092		INIT_WORK(&sfw->work, flush_cpu_slab);
3093		sfw->skip = false;
3094		sfw->s = s;
3095		queue_work_on(cpu, flushwq, &sfw->work);
3096	}
3097
3098	for_each_online_cpu(cpu) {
3099		sfw = &per_cpu(slub_flush, cpu);
3100		if (sfw->skip)
3101			continue;
3102		flush_work(&sfw->work);
3103	}
3104
3105	mutex_unlock(&flush_lock);
3106}
3107
3108static void flush_all(struct kmem_cache *s)
3109{
3110	cpus_read_lock();
3111	flush_all_cpus_locked(s);
3112	cpus_read_unlock();
3113}
3114
3115/*
3116 * Use the cpu notifier to insure that the cpu slabs are flushed when
3117 * necessary.
3118 */
3119static int slub_cpu_dead(unsigned int cpu)
3120{
3121	struct kmem_cache *s;
 
3122
3123	mutex_lock(&slab_mutex);
3124	list_for_each_entry(s, &slab_caches, list)
 
3125		__flush_cpu_slab(s, cpu);
 
 
3126	mutex_unlock(&slab_mutex);
3127	return 0;
3128}
3129
3130#else /* CONFIG_SLUB_TINY */
3131static inline void flush_all_cpus_locked(struct kmem_cache *s) { }
3132static inline void flush_all(struct kmem_cache *s) { }
3133static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) { }
3134static inline int slub_cpu_dead(unsigned int cpu) { return 0; }
3135#endif /* CONFIG_SLUB_TINY */
3136
3137/*
3138 * Check if the objects in a per cpu structure fit numa
3139 * locality expectations.
3140 */
3141static inline int node_match(struct slab *slab, int node)
3142{
3143#ifdef CONFIG_NUMA
3144	if (node != NUMA_NO_NODE && slab_nid(slab) != node)
3145		return 0;
3146#endif
3147	return 1;
3148}
3149
3150#ifdef CONFIG_SLUB_DEBUG
3151static int count_free(struct slab *slab)
3152{
3153	return slab->objects - slab->inuse;
3154}
3155
3156static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
3157{
3158	return atomic_long_read(&n->total_objects);
3159}
3160
3161/* Supports checking bulk free of a constructed freelist */
3162static inline bool free_debug_processing(struct kmem_cache *s,
3163	struct slab *slab, void *head, void *tail, int *bulk_cnt,
3164	unsigned long addr, depot_stack_handle_t handle)
3165{
3166	bool checks_ok = false;
3167	void *object = head;
3168	int cnt = 0;
3169
3170	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
3171		if (!check_slab(s, slab))
3172			goto out;
3173	}
3174
3175	if (slab->inuse < *bulk_cnt) {
3176		slab_err(s, slab, "Slab has %d allocated objects but %d are to be freed\n",
3177			 slab->inuse, *bulk_cnt);
3178		goto out;
3179	}
3180
3181next_object:
3182
3183	if (++cnt > *bulk_cnt)
3184		goto out_cnt;
3185
3186	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
3187		if (!free_consistency_checks(s, slab, object, addr))
3188			goto out;
3189	}
3190
3191	if (s->flags & SLAB_STORE_USER)
3192		set_track_update(s, object, TRACK_FREE, addr, handle);
3193	trace(s, slab, object, 0);
3194	/* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
3195	init_object(s, object, SLUB_RED_INACTIVE);
3196
3197	/* Reached end of constructed freelist yet? */
3198	if (object != tail) {
3199		object = get_freepointer(s, object);
3200		goto next_object;
3201	}
3202	checks_ok = true;
3203
3204out_cnt:
3205	if (cnt != *bulk_cnt) {
3206		slab_err(s, slab, "Bulk free expected %d objects but found %d\n",
3207			 *bulk_cnt, cnt);
3208		*bulk_cnt = cnt;
3209	}
3210
3211out:
3212
3213	if (!checks_ok)
3214		slab_fix(s, "Object at 0x%p not freed", object);
3215
3216	return checks_ok;
3217}
3218#endif /* CONFIG_SLUB_DEBUG */
3219
3220#if defined(CONFIG_SLUB_DEBUG) || defined(SLAB_SUPPORTS_SYSFS)
3221static unsigned long count_partial(struct kmem_cache_node *n,
3222					int (*get_count)(struct slab *))
3223{
3224	unsigned long flags;
3225	unsigned long x = 0;
3226	struct slab *slab;
3227
3228	spin_lock_irqsave(&n->list_lock, flags);
3229	list_for_each_entry(slab, &n->partial, slab_list)
3230		x += get_count(slab);
3231	spin_unlock_irqrestore(&n->list_lock, flags);
3232	return x;
3233}
3234#endif /* CONFIG_SLUB_DEBUG || SLAB_SUPPORTS_SYSFS */
3235
3236#ifdef CONFIG_SLUB_DEBUG
3237static noinline void
3238slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
3239{
 
3240	static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
3241				      DEFAULT_RATELIMIT_BURST);
3242	int node;
3243	struct kmem_cache_node *n;
3244
3245	if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
3246		return;
3247
3248	pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
3249		nid, gfpflags, &gfpflags);
3250	pr_warn("  cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
3251		s->name, s->object_size, s->size, oo_order(s->oo),
3252		oo_order(s->min));
3253
3254	if (oo_order(s->min) > get_order(s->object_size))
3255		pr_warn("  %s debugging increased min order, use slab_debug=O to disable.\n",
3256			s->name);
3257
3258	for_each_kmem_cache_node(s, node, n) {
3259		unsigned long nr_slabs;
3260		unsigned long nr_objs;
3261		unsigned long nr_free;
3262
3263		nr_free  = count_partial(n, count_free);
3264		nr_slabs = node_nr_slabs(n);
3265		nr_objs  = node_nr_objs(n);
3266
3267		pr_warn("  node %d: slabs: %ld, objs: %ld, free: %ld\n",
3268			node, nr_slabs, nr_objs, nr_free);
3269	}
3270}
3271#else /* CONFIG_SLUB_DEBUG */
3272static inline void
3273slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) { }
3274#endif
3275
3276static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
3277{
3278	if (unlikely(slab_test_pfmemalloc(slab)))
3279		return gfp_pfmemalloc_allowed(gfpflags);
3280
3281	return true;
3282}
3283
3284#ifndef CONFIG_SLUB_TINY
3285static inline bool
3286__update_cpu_freelist_fast(struct kmem_cache *s,
3287			   void *freelist_old, void *freelist_new,
3288			   unsigned long tid)
3289{
3290	freelist_aba_t old = { .freelist = freelist_old, .counter = tid };
3291	freelist_aba_t new = { .freelist = freelist_new, .counter = next_tid(tid) };
3292
3293	return this_cpu_try_cmpxchg_freelist(s->cpu_slab->freelist_tid.full,
3294					     &old.full, new.full);
3295}
3296
3297/*
3298 * Check the slab->freelist and either transfer the freelist to the
3299 * per cpu freelist or deactivate the slab.
3300 *
3301 * The slab is still frozen if the return value is not NULL.
3302 *
3303 * If this function returns NULL then the slab has been unfrozen.
3304 */
3305static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
3306{
3307	struct slab new;
3308	unsigned long counters;
3309	void *freelist;
 
 
3310
3311	lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
3312
3313	do {
3314		freelist = slab->freelist;
3315		counters = slab->counters;
3316
3317		new.counters = counters;
 
3318
3319		new.inuse = slab->objects;
3320		new.frozen = freelist != NULL;
 
 
 
3321
3322	} while (!__slab_update_freelist(s, slab,
3323		freelist, counters,
3324		NULL, new.counters,
3325		"get_freelist"));
 
 
 
 
 
 
 
3326
3327	return freelist;
3328}
3329
 
 
 
 
 
 
 
 
3330/*
3331 * Freeze the partial slab and return the pointer to the freelist.
 
 
 
 
 
 
 
3332 */
3333static inline void *freeze_slab(struct kmem_cache *s, struct slab *slab)
3334{
3335	struct slab new;
3336	unsigned long counters;
3337	void *freelist;
3338
3339	do {
3340		freelist = slab->freelist;
3341		counters = slab->counters;
3342
3343		new.counters = counters;
3344		VM_BUG_ON(new.frozen);
3345
3346		new.inuse = slab->objects;
3347		new.frozen = 1;
3348
3349	} while (!slab_update_freelist(s, slab,
3350		freelist, counters,
3351		NULL, new.counters,
3352		"freeze_slab"));
3353
3354	return freelist;
3355}
3356
3357/*
3358 * Slow path. The lockless freelist is empty or we need to perform
3359 * debugging duties.
3360 *
3361 * Processing is still very fast if new objects have been freed to the
3362 * regular freelist. In that case we simply take over the regular freelist
3363 * as the lockless freelist and zap the regular freelist.
3364 *
3365 * If that is not working then we fall back to the partial lists. We take the
3366 * first element of the freelist as the object to allocate now and move the
3367 * rest of the freelist to the lockless freelist.
3368 *
3369 * And if we were unable to get a new slab from the partial slab lists then
3370 * we need to allocate a new slab. This is the slowest path since it involves
3371 * a call to the page allocator and the setup of a new slab.
3372 *
3373 * Version of __slab_alloc to use when we know that preemption is
3374 * already disabled (which is the case for bulk allocation).
3375 */
3376static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3377			  unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
3378{
3379	void *freelist;
3380	struct slab *slab;
3381	unsigned long flags;
3382	struct partial_context pc;
3383
3384	stat(s, ALLOC_SLOWPATH);
3385
3386reread_slab:
3387
3388	slab = READ_ONCE(c->slab);
3389	if (!slab) {
3390		/*
3391		 * if the node is not online or has no normal memory, just
3392		 * ignore the node constraint
3393		 */
3394		if (unlikely(node != NUMA_NO_NODE &&
3395			     !node_isset(node, slab_nodes)))
3396			node = NUMA_NO_NODE;
3397		goto new_slab;
3398	}
 
3399
3400	if (unlikely(!node_match(slab, node))) {
3401		/*
3402		 * same as above but node_match() being false already
3403		 * implies node != NUMA_NO_NODE
3404		 */
3405		if (!node_isset(node, slab_nodes)) {
3406			node = NUMA_NO_NODE;
 
3407		} else {
3408			stat(s, ALLOC_NODE_MISMATCH);
3409			goto deactivate_slab;
 
3410		}
3411	}
3412
3413	/*
3414	 * By rights, we should be searching for a slab page that was
3415	 * PFMEMALLOC but right now, we are losing the pfmemalloc
3416	 * information when the page leaves the per-cpu allocator
3417	 */
3418	if (unlikely(!pfmemalloc_match(slab, gfpflags)))
3419		goto deactivate_slab;
3420
3421	/* must check again c->slab in case we got preempted and it changed */
3422	local_lock_irqsave(&s->cpu_slab->lock, flags);
3423	if (unlikely(slab != c->slab)) {
3424		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3425		goto reread_slab;
3426	}
 
 
3427	freelist = c->freelist;
3428	if (freelist)
3429		goto load_freelist;
3430
3431	freelist = get_freelist(s, slab);
3432
3433	if (!freelist) {
3434		c->slab = NULL;
3435		c->tid = next_tid(c->tid);
3436		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3437		stat(s, DEACTIVATE_BYPASS);
3438		goto new_slab;
3439	}
3440
3441	stat(s, ALLOC_REFILL);
3442
3443load_freelist:
3444
3445	lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
3446
3447	/*
3448	 * freelist is pointing to the list of objects to be used.
3449	 * slab is pointing to the slab from which the objects are obtained.
3450	 * That slab must be frozen for per cpu allocations to work.
3451	 */
3452	VM_BUG_ON(!c->slab->frozen);
3453	c->freelist = get_freepointer(s, freelist);
3454	c->tid = next_tid(c->tid);
3455	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3456	return freelist;
3457
3458deactivate_slab:
3459
3460	local_lock_irqsave(&s->cpu_slab->lock, flags);
3461	if (slab != c->slab) {
3462		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3463		goto reread_slab;
3464	}
3465	freelist = c->freelist;
3466	c->slab = NULL;
3467	c->freelist = NULL;
3468	c->tid = next_tid(c->tid);
3469	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3470	deactivate_slab(s, slab, freelist);
3471
3472new_slab:
3473
3474#ifdef CONFIG_SLUB_CPU_PARTIAL
3475	while (slub_percpu_partial(c)) {
3476		local_lock_irqsave(&s->cpu_slab->lock, flags);
3477		if (unlikely(c->slab)) {
3478			local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3479			goto reread_slab;
3480		}
3481		if (unlikely(!slub_percpu_partial(c))) {
3482			local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3483			/* we were preempted and partial list got empty */
3484			goto new_objects;
3485		}
3486
3487		slab = slub_percpu_partial(c);
3488		slub_set_percpu_partial(c, slab);
3489
3490		if (likely(node_match(slab, node) &&
3491			   pfmemalloc_match(slab, gfpflags))) {
3492			c->slab = slab;
3493			freelist = get_freelist(s, slab);
3494			VM_BUG_ON(!freelist);
3495			stat(s, CPU_PARTIAL_ALLOC);
3496			goto load_freelist;
3497		}
3498
3499		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3500
3501		slab->next = NULL;
3502		__put_partials(s, slab);
3503	}
3504#endif
3505
3506new_objects:
3507
3508	pc.flags = gfpflags;
3509	pc.orig_size = orig_size;
3510	slab = get_partial(s, node, &pc);
3511	if (slab) {
3512		if (kmem_cache_debug(s)) {
3513			freelist = pc.object;
3514			/*
3515			 * For debug caches here we had to go through
3516			 * alloc_single_from_partial() so just store the
3517			 * tracking info and return the object.
3518			 */
3519			if (s->flags & SLAB_STORE_USER)
3520				set_track(s, freelist, TRACK_ALLOC, addr);
3521
3522			return freelist;
3523		}
3524
3525		freelist = freeze_slab(s, slab);
3526		goto retry_load_slab;
3527	}
3528
3529	slub_put_cpu_ptr(s->cpu_slab);
3530	slab = new_slab(s, gfpflags, node);
3531	c = slub_get_cpu_ptr(s->cpu_slab);
3532
3533	if (unlikely(!slab)) {
3534		slab_out_of_memory(s, gfpflags, node);
3535		return NULL;
3536	}
3537
3538	stat(s, ALLOC_SLAB);
3539
3540	if (kmem_cache_debug(s)) {
3541		freelist = alloc_single_from_new_slab(s, slab, orig_size);
3542
3543		if (unlikely(!freelist))
3544			goto new_objects;
3545
3546		if (s->flags & SLAB_STORE_USER)
3547			set_track(s, freelist, TRACK_ALLOC, addr);
3548
3549		return freelist;
3550	}
3551
3552	/*
3553	 * No other reference to the slab yet so we can
3554	 * muck around with it freely without cmpxchg
3555	 */
3556	freelist = slab->freelist;
3557	slab->freelist = NULL;
3558	slab->inuse = slab->objects;
3559	slab->frozen = 1;
3560
3561	inc_slabs_node(s, slab_nid(slab), slab->objects);
3562
3563	if (unlikely(!pfmemalloc_match(slab, gfpflags))) {
3564		/*
3565		 * For !pfmemalloc_match() case we don't load freelist so that
3566		 * we don't make further mismatched allocations easier.
3567		 */
3568		deactivate_slab(s, slab, get_freepointer(s, freelist));
3569		return freelist;
3570	}
3571
3572retry_load_slab:
3573
3574	local_lock_irqsave(&s->cpu_slab->lock, flags);
3575	if (unlikely(c->slab)) {
3576		void *flush_freelist = c->freelist;
3577		struct slab *flush_slab = c->slab;
3578
3579		c->slab = NULL;
3580		c->freelist = NULL;
3581		c->tid = next_tid(c->tid);
3582
3583		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3584
3585		deactivate_slab(s, flush_slab, flush_freelist);
3586
3587		stat(s, CPUSLAB_FLUSH);
3588
3589		goto retry_load_slab;
3590	}
3591	c->slab = slab;
 
3592
3593	goto load_freelist;
 
3594}
3595
3596/*
3597 * A wrapper for ___slab_alloc() for contexts where preemption is not yet
3598 * disabled. Compensates for possible cpu changes by refetching the per cpu area
3599 * pointer.
3600 */
3601static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3602			  unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
3603{
3604	void *p;
 
3605
3606#ifdef CONFIG_PREEMPT_COUNT
 
3607	/*
3608	 * We may have been preempted and rescheduled on a different
3609	 * cpu before disabling preemption. Need to reload cpu area
3610	 * pointer.
3611	 */
3612	c = slub_get_cpu_ptr(s->cpu_slab);
3613#endif
3614
3615	p = ___slab_alloc(s, gfpflags, node, addr, c, orig_size);
3616#ifdef CONFIG_PREEMPT_COUNT
3617	slub_put_cpu_ptr(s->cpu_slab);
3618#endif
3619	return p;
3620}
3621
3622static __always_inline void *__slab_alloc_node(struct kmem_cache *s,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3623		gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3624{
 
3625	struct kmem_cache_cpu *c;
3626	struct slab *slab;
3627	unsigned long tid;
3628	void *object;
 
 
 
 
 
 
 
 
 
3629
3630redo:
3631	/*
3632	 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
3633	 * enabled. We may switch back and forth between cpus while
3634	 * reading from one cpu area. That does not matter as long
3635	 * as we end up on the original cpu again when doing the cmpxchg.
3636	 *
3637	 * We must guarantee that tid and kmem_cache_cpu are retrieved on the
3638	 * same cpu. We read first the kmem_cache_cpu pointer and use it to read
3639	 * the tid. If we are preempted and switched to another cpu between the
3640	 * two reads, it's OK as the two are still associated with the same cpu
3641	 * and cmpxchg later will validate the cpu.
3642	 */
3643	c = raw_cpu_ptr(s->cpu_slab);
3644	tid = READ_ONCE(c->tid);
 
 
 
3645
3646	/*
3647	 * Irqless object alloc/free algorithm used here depends on sequence
3648	 * of fetching cpu_slab's data. tid should be fetched before anything
3649	 * on c to guarantee that object and slab associated with previous tid
3650	 * won't be used with current tid. If we fetch tid first, object and
3651	 * slab could be one associated with next tid and our alloc/free
3652	 * request will be failed. In this case, we will retry. So, no problem.
3653	 */
3654	barrier();
3655
3656	/*
3657	 * The transaction ids are globally unique per cpu and per operation on
3658	 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
3659	 * occurs on the right processor and that there was no operation on the
3660	 * linked list in between.
3661	 */
3662
3663	object = c->freelist;
3664	slab = c->slab;
3665
3666	if (!USE_LOCKLESS_FAST_PATH() ||
3667	    unlikely(!object || !slab || !node_match(slab, node))) {
3668		object = __slab_alloc(s, gfpflags, node, addr, c, orig_size);
3669	} else {
3670		void *next_object = get_freepointer_safe(s, object);
3671
3672		/*
3673		 * The cmpxchg will only match if there was no additional
3674		 * operation and if we are on the right processor.
3675		 *
3676		 * The cmpxchg does the following atomically (without lock
3677		 * semantics!)
3678		 * 1. Relocate first pointer to the current per cpu area.
3679		 * 2. Verify that tid and freelist have not been changed
3680		 * 3. If they were not changed replace tid and freelist
3681		 *
3682		 * Since this is without lock semantics the protection is only
3683		 * against code executing on this cpu *not* from access by
3684		 * other cpus.
3685		 */
3686		if (unlikely(!__update_cpu_freelist_fast(s, object, next_object, tid))) {
 
 
 
 
3687			note_cmpxchg_failure("slab_alloc", s, tid);
3688			goto redo;
3689		}
3690		prefetch_freepointer(s, next_object);
3691		stat(s, ALLOC_FASTPATH);
3692	}
3693
3694	return object;
3695}
3696#else /* CONFIG_SLUB_TINY */
3697static void *__slab_alloc_node(struct kmem_cache *s,
3698		gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3699{
3700	struct partial_context pc;
3701	struct slab *slab;
3702	void *object;
3703
3704	pc.flags = gfpflags;
3705	pc.orig_size = orig_size;
3706	slab = get_partial(s, node, &pc);
3707
3708	if (slab)
3709		return pc.object;
3710
3711	slab = new_slab(s, gfpflags, node);
3712	if (unlikely(!slab)) {
3713		slab_out_of_memory(s, gfpflags, node);
3714		return NULL;
3715	}
3716
3717	object = alloc_single_from_new_slab(s, slab, orig_size);
3718
3719	return object;
3720}
3721#endif /* CONFIG_SLUB_TINY */
3722
3723/*
3724 * If the object has been wiped upon free, make sure it's fully initialized by
3725 * zeroing out freelist pointer.
3726 */
3727static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
3728						   void *obj)
3729{
3730	if (unlikely(slab_want_init_on_free(s)) && obj &&
3731	    !freeptr_outside_object(s))
3732		memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
3733			0, sizeof(void *));
3734}
3735
3736noinline int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
3737{
3738	if (__should_failslab(s, gfpflags))
3739		return -ENOMEM;
3740	return 0;
3741}
3742ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
3743
3744static __fastpath_inline
3745struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
3746				       struct list_lru *lru,
3747				       struct obj_cgroup **objcgp,
3748				       size_t size, gfp_t flags)
3749{
3750	flags &= gfp_allowed_mask;
3751
3752	might_alloc(flags);
3753
3754	if (unlikely(should_failslab(s, flags)))
3755		return NULL;
3756
3757	if (unlikely(!memcg_slab_pre_alloc_hook(s, lru, objcgp, size, flags)))
3758		return NULL;
3759
3760	return s;
3761}
3762
3763static __fastpath_inline
3764void slab_post_alloc_hook(struct kmem_cache *s,	struct obj_cgroup *objcg,
3765			  gfp_t flags, size_t size, void **p, bool init,
3766			  unsigned int orig_size)
3767{
3768	unsigned int zero_size = s->object_size;
3769	bool kasan_init = init;
3770	size_t i;
3771	gfp_t init_flags = flags & gfp_allowed_mask;
3772
3773	/*
3774	 * For kmalloc object, the allocated memory size(object_size) is likely
3775	 * larger than the requested size(orig_size). If redzone check is
3776	 * enabled for the extra space, don't zero it, as it will be redzoned
3777	 * soon. The redzone operation for this extra space could be seen as a
3778	 * replacement of current poisoning under certain debug option, and
3779	 * won't break other sanity checks.
3780	 */
3781	if (kmem_cache_debug_flags(s, SLAB_STORE_USER | SLAB_RED_ZONE) &&
3782	    (s->flags & SLAB_KMALLOC))
3783		zero_size = orig_size;
3784
3785	/*
3786	 * When slab_debug is enabled, avoid memory initialization integrated
3787	 * into KASAN and instead zero out the memory via the memset below with
3788	 * the proper size. Otherwise, KASAN might overwrite SLUB redzones and
3789	 * cause false-positive reports. This does not lead to a performance
3790	 * penalty on production builds, as slab_debug is not intended to be
3791	 * enabled there.
3792	 */
3793	if (__slub_debug_enabled())
3794		kasan_init = false;
3795
3796	/*
3797	 * As memory initialization might be integrated into KASAN,
3798	 * kasan_slab_alloc and initialization memset must be
3799	 * kept together to avoid discrepancies in behavior.
3800	 *
3801	 * As p[i] might get tagged, memset and kmemleak hook come after KASAN.
3802	 */
3803	for (i = 0; i < size; i++) {
3804		p[i] = kasan_slab_alloc(s, p[i], init_flags, kasan_init);
3805		if (p[i] && init && (!kasan_init ||
3806				     !kasan_has_integrated_init()))
3807			memset(p[i], 0, zero_size);
3808		kmemleak_alloc_recursive(p[i], s->object_size, 1,
3809					 s->flags, init_flags);
3810		kmsan_slab_alloc(s, p[i], init_flags);
3811	}
3812
3813	memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
3814}
3815
3816/*
3817 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
3818 * have the fastpath folded into their functions. So no function call
3819 * overhead for requests that can be satisfied on the fastpath.
3820 *
3821 * The fastpath works by first checking if the lockless freelist can be used.
3822 * If not then __slab_alloc is called for slow processing.
3823 *
3824 * Otherwise we can simply pick the next object from the lockless free list.
3825 */
3826static __fastpath_inline void *slab_alloc_node(struct kmem_cache *s, struct list_lru *lru,
3827		gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3828{
3829	void *object;
3830	struct obj_cgroup *objcg = NULL;
3831	bool init = false;
3832
3833	s = slab_pre_alloc_hook(s, lru, &objcg, 1, gfpflags);
3834	if (unlikely(!s))
3835		return NULL;
3836
3837	object = kfence_alloc(s, orig_size, gfpflags);
3838	if (unlikely(object))
3839		goto out;
3840
3841	object = __slab_alloc_node(s, gfpflags, node, addr, orig_size);
3842
3843	maybe_wipe_obj_freeptr(s, object);
3844	init = slab_want_init_on_alloc(gfpflags, s);
3845
3846out:
3847	/*
3848	 * When init equals 'true', like for kzalloc() family, only
3849	 * @orig_size bytes might be zeroed instead of s->object_size
3850	 */
3851	slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init, orig_size);
3852
3853	return object;
3854}
3855
 
 
 
 
 
 
3856void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
3857{
3858	void *ret = slab_alloc_node(s, NULL, gfpflags, NUMA_NO_NODE, _RET_IP_,
3859				    s->object_size);
3860
3861	trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
 
3862
3863	return ret;
3864}
3865EXPORT_SYMBOL(kmem_cache_alloc);
3866
3867void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
3868			   gfp_t gfpflags)
3869{
3870	void *ret = slab_alloc_node(s, lru, gfpflags, NUMA_NO_NODE, _RET_IP_,
3871				    s->object_size);
3872
3873	trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
3874
3875	return ret;
3876}
3877EXPORT_SYMBOL(kmem_cache_alloc_lru);
 
3878
3879/**
3880 * kmem_cache_alloc_node - Allocate an object on the specified node
3881 * @s: The cache to allocate from.
3882 * @gfpflags: See kmalloc().
3883 * @node: node number of the target node.
3884 *
3885 * Identical to kmem_cache_alloc but it will allocate memory on the given
3886 * node, which can improve the performance for cpu bound structures.
3887 *
3888 * Fallback to other node is possible if __GFP_THISNODE is not set.
3889 *
3890 * Return: pointer to the new object or %NULL in case of error
3891 */
3892void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
3893{
3894	void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
3895
3896	trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);
 
3897
3898	return ret;
3899}
3900EXPORT_SYMBOL(kmem_cache_alloc_node);
3901
3902/*
3903 * To avoid unnecessary overhead, we pass through large allocation requests
3904 * directly to the page allocator. We use __GFP_COMP, because we will need to
3905 * know the allocation order to free the pages properly in kfree.
3906 */
3907static void *__kmalloc_large_node(size_t size, gfp_t flags, int node)
3908{
3909	struct folio *folio;
3910	void *ptr = NULL;
3911	unsigned int order = get_order(size);
3912
3913	if (unlikely(flags & GFP_SLAB_BUG_MASK))
3914		flags = kmalloc_fix_flags(flags);
3915
3916	flags |= __GFP_COMP;
3917	folio = (struct folio *)alloc_pages_node(node, flags, order);
3918	if (folio) {
3919		ptr = folio_address(folio);
3920		lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
3921				      PAGE_SIZE << order);
3922	}
3923
3924	ptr = kasan_kmalloc_large(ptr, size, flags);
3925	/* As ptr might get tagged, call kmemleak hook after KASAN. */
3926	kmemleak_alloc(ptr, size, 1, flags);
3927	kmsan_kmalloc_large(ptr, size, flags);
3928
3929	return ptr;
3930}
3931
3932void *kmalloc_large(size_t size, gfp_t flags)
3933{
3934	void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE);
3935
3936	trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
3937		      flags, NUMA_NO_NODE);
3938	return ret;
3939}
3940EXPORT_SYMBOL(kmalloc_large);
3941
3942void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3943{
3944	void *ret = __kmalloc_large_node(size, flags, node);
3945
3946	trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
3947		      flags, node);
3948	return ret;
3949}
3950EXPORT_SYMBOL(kmalloc_large_node);
3951
3952static __always_inline
3953void *__do_kmalloc_node(size_t size, gfp_t flags, int node,
3954			unsigned long caller)
3955{
3956	struct kmem_cache *s;
3957	void *ret;
3958
3959	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3960		ret = __kmalloc_large_node(size, flags, node);
3961		trace_kmalloc(caller, ret, size,
3962			      PAGE_SIZE << get_order(size), flags, node);
3963		return ret;
3964	}
3965
3966	if (unlikely(!size))
3967		return ZERO_SIZE_PTR;
3968
3969	s = kmalloc_slab(size, flags, caller);
3970
3971	ret = slab_alloc_node(s, NULL, flags, node, caller, size);
3972	ret = kasan_kmalloc(s, ret, size, flags);
3973	trace_kmalloc(caller, ret, size, s->size, flags, node);
3974	return ret;
3975}
3976
3977void *__kmalloc_node(size_t size, gfp_t flags, int node)
3978{
3979	return __do_kmalloc_node(size, flags, node, _RET_IP_);
3980}
3981EXPORT_SYMBOL(__kmalloc_node);
3982
3983void *__kmalloc(size_t size, gfp_t flags)
3984{
3985	return __do_kmalloc_node(size, flags, NUMA_NO_NODE, _RET_IP_);
3986}
3987EXPORT_SYMBOL(__kmalloc);
3988
3989void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3990				  int node, unsigned long caller)
3991{
3992	return __do_kmalloc_node(size, flags, node, caller);
3993}
3994EXPORT_SYMBOL(__kmalloc_node_track_caller);
3995
3996void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
3997{
3998	void *ret = slab_alloc_node(s, NULL, gfpflags, NUMA_NO_NODE,
3999					    _RET_IP_, size);
4000
4001	trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE);
 
4002
4003	ret = kasan_kmalloc(s, ret, size, gfpflags);
4004	return ret;
4005}
4006EXPORT_SYMBOL(kmalloc_trace);
4007
4008void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
4009			 int node, size_t size)
4010{
4011	void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, size);
4012
4013	trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node);
4014
4015	ret = kasan_kmalloc(s, ret, size, gfpflags);
4016	return ret;
4017}
4018EXPORT_SYMBOL(kmalloc_node_trace);
4019
4020static noinline void free_to_partial_list(
4021	struct kmem_cache *s, struct slab *slab,
4022	void *head, void *tail, int bulk_cnt,
4023	unsigned long addr)
4024{
4025	struct kmem_cache_node *n = get_node(s, slab_nid(slab));
4026	struct slab *slab_free = NULL;
4027	int cnt = bulk_cnt;
4028	unsigned long flags;
4029	depot_stack_handle_t handle = 0;
4030
4031	if (s->flags & SLAB_STORE_USER)
4032		handle = set_track_prepare();
4033
4034	spin_lock_irqsave(&n->list_lock, flags);
4035
4036	if (free_debug_processing(s, slab, head, tail, &cnt, addr, handle)) {
4037		void *prior = slab->freelist;
4038
4039		/* Perform the actual freeing while we still hold the locks */
4040		slab->inuse -= cnt;
4041		set_freepointer(s, tail, prior);
4042		slab->freelist = head;
4043
4044		/*
4045		 * If the slab is empty, and node's partial list is full,
4046		 * it should be discarded anyway no matter it's on full or
4047		 * partial list.
4048		 */
4049		if (slab->inuse == 0 && n->nr_partial >= s->min_partial)
4050			slab_free = slab;
4051
4052		if (!prior) {
4053			/* was on full list */
4054			remove_full(s, n, slab);
4055			if (!slab_free) {
4056				add_partial(n, slab, DEACTIVATE_TO_TAIL);
4057				stat(s, FREE_ADD_PARTIAL);
4058			}
4059		} else if (slab_free) {
4060			remove_partial(n, slab);
4061			stat(s, FREE_REMOVE_PARTIAL);
4062		}
4063	}
4064
4065	if (slab_free) {
4066		/*
4067		 * Update the counters while still holding n->list_lock to
4068		 * prevent spurious validation warnings
4069		 */
4070		dec_slabs_node(s, slab_nid(slab_free), slab_free->objects);
4071	}
4072
4073	spin_unlock_irqrestore(&n->list_lock, flags);
4074
4075	if (slab_free) {
4076		stat(s, FREE_SLAB);
4077		free_slab(s, slab_free);
4078	}
4079}
4080
4081/*
4082 * Slow path handling. This may still be called frequently since objects
4083 * have a longer lifetime than the cpu slabs in most processing loads.
4084 *
4085 * So we still attempt to reduce cache line usage. Just take the slab
4086 * lock and free the item. If there is no additional partial slab
4087 * handling required then we can return immediately.
4088 */
4089static void __slab_free(struct kmem_cache *s, struct slab *slab,
4090			void *head, void *tail, int cnt,
4091			unsigned long addr)
4092
4093{
4094	void *prior;
4095	int was_frozen;
4096	struct slab new;
4097	unsigned long counters;
4098	struct kmem_cache_node *n = NULL;
4099	unsigned long flags;
4100	bool on_node_partial;
4101
4102	stat(s, FREE_SLOWPATH);
4103
4104	if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
4105		free_to_partial_list(s, slab, head, tail, cnt, addr);
 
 
 
4106		return;
4107	}
4108
4109	do {
4110		if (unlikely(n)) {
4111			spin_unlock_irqrestore(&n->list_lock, flags);
4112			n = NULL;
4113		}
4114		prior = slab->freelist;
4115		counters = slab->counters;
4116		set_freepointer(s, tail, prior);
4117		new.counters = counters;
4118		was_frozen = new.frozen;
4119		new.inuse -= cnt;
4120		if ((!new.inuse || !prior) && !was_frozen) {
4121			/* Needs to be taken off a list */
4122			if (!kmem_cache_has_cpu_partial(s) || prior) {
4123
4124				n = get_node(s, slab_nid(slab));
 
 
 
 
 
 
 
 
 
 
 
 
4125				/*
4126				 * Speculatively acquire the list_lock.
4127				 * If the cmpxchg does not succeed then we may
4128				 * drop the list_lock without any processing.
4129				 *
4130				 * Otherwise the list_lock will synchronize with
4131				 * other processors updating the list of slabs.
4132				 */
4133				spin_lock_irqsave(&n->list_lock, flags);
4134
4135				on_node_partial = slab_test_node_partial(slab);
4136			}
4137		}
4138
4139	} while (!slab_update_freelist(s, slab,
4140		prior, counters,
4141		head, new.counters,
4142		"__slab_free"));
4143
4144	if (likely(!n)) {
4145
4146		if (likely(was_frozen)) {
4147			/*
4148			 * The list lock was not taken therefore no list
4149			 * activity can be necessary.
4150			 */
4151			stat(s, FREE_FROZEN);
4152		} else if (kmem_cache_has_cpu_partial(s) && !prior) {
4153			/*
4154			 * If we started with a full slab then put it onto the
4155			 * per cpu partial list.
4156			 */
4157			put_cpu_partial(s, slab, 1);
4158			stat(s, CPU_PARTIAL_FREE);
4159		}
4160
4161		return;
4162	}
4163
4164	/*
4165	 * This slab was partially empty but not on the per-node partial list,
4166	 * in which case we shouldn't manipulate its list, just return.
4167	 */
4168	if (prior && !on_node_partial) {
4169		spin_unlock_irqrestore(&n->list_lock, flags);
4170		return;
4171	}
4172
4173	if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
4174		goto slab_empty;
4175
4176	/*
4177	 * Objects left in the slab. If it was not on the partial list before
4178	 * then add it.
4179	 */
4180	if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
4181		add_partial(n, slab, DEACTIVATE_TO_TAIL);
 
4182		stat(s, FREE_ADD_PARTIAL);
4183	}
4184	spin_unlock_irqrestore(&n->list_lock, flags);
4185	return;
4186
4187slab_empty:
4188	if (prior) {
4189		/*
4190		 * Slab on the partial list.
4191		 */
4192		remove_partial(n, slab);
4193		stat(s, FREE_REMOVE_PARTIAL);
 
 
 
4194	}
4195
4196	spin_unlock_irqrestore(&n->list_lock, flags);
4197	stat(s, FREE_SLAB);
4198	discard_slab(s, slab);
4199}
4200
4201#ifndef CONFIG_SLUB_TINY
4202/*
4203 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
4204 * can perform fastpath freeing without additional function calls.
4205 *
4206 * The fastpath is only possible if we are freeing to the current cpu slab
4207 * of this processor. This typically the case if we have just allocated
4208 * the item before.
4209 *
4210 * If fastpath is not possible then fall back to __slab_free where we deal
4211 * with all sorts of special processing.
4212 *
4213 * Bulk free of a freelist with several objects (all pointing to the
4214 * same slab) possible by specifying head and tail ptr, plus objects
4215 * count (cnt). Bulk free indicated by tail pointer being set.
4216 */
4217static __always_inline void do_slab_free(struct kmem_cache *s,
4218				struct slab *slab, void *head, void *tail,
4219				int cnt, unsigned long addr)
4220{
 
4221	struct kmem_cache_cpu *c;
4222	unsigned long tid;
4223	void **freelist;
4224
 
 
 
4225redo:
4226	/*
4227	 * Determine the currently cpus per cpu slab.
4228	 * The cpu may change afterward. However that does not matter since
4229	 * data is retrieved via this pointer. If we are on the same cpu
4230	 * during the cmpxchg then the free will succeed.
4231	 */
4232	c = raw_cpu_ptr(s->cpu_slab);
4233	tid = READ_ONCE(c->tid);
 
 
 
4234
4235	/* Same with comment on barrier() in slab_alloc_node() */
4236	barrier();
4237
4238	if (unlikely(slab != c->slab)) {
4239		__slab_free(s, slab, head, tail, cnt, addr);
4240		return;
4241	}
4242
4243	if (USE_LOCKLESS_FAST_PATH()) {
4244		freelist = READ_ONCE(c->freelist);
4245
4246		set_freepointer(s, tail, freelist);
 
 
 
4247
4248		if (unlikely(!__update_cpu_freelist_fast(s, freelist, head, tid))) {
4249			note_cmpxchg_failure("slab_free", s, tid);
4250			goto redo;
4251		}
4252	} else {
4253		/* Update the free list under the local lock */
4254		local_lock(&s->cpu_slab->lock);
4255		c = this_cpu_ptr(s->cpu_slab);
4256		if (unlikely(slab != c->slab)) {
4257			local_unlock(&s->cpu_slab->lock);
4258			goto redo;
4259		}
4260		tid = c->tid;
4261		freelist = c->freelist;
4262
4263		set_freepointer(s, tail, freelist);
4264		c->freelist = head;
4265		c->tid = next_tid(tid);
4266
4267		local_unlock(&s->cpu_slab->lock);
4268	}
4269	stat_add(s, FREE_FASTPATH, cnt);
4270}
4271#else /* CONFIG_SLUB_TINY */
4272static void do_slab_free(struct kmem_cache *s,
4273				struct slab *slab, void *head, void *tail,
4274				int cnt, unsigned long addr)
4275{
4276	__slab_free(s, slab, head, tail, cnt, addr);
4277}
4278#endif /* CONFIG_SLUB_TINY */
4279
4280static __fastpath_inline
4281void slab_free(struct kmem_cache *s, struct slab *slab, void *object,
4282	       unsigned long addr)
4283{
4284	memcg_slab_free_hook(s, slab, &object, 1);
4285
4286	if (likely(slab_free_hook(s, object, slab_want_init_on_free(s))))
4287		do_slab_free(s, slab, object, object, 1, addr);
4288}
4289
4290static __fastpath_inline
4291void slab_free_bulk(struct kmem_cache *s, struct slab *slab, void *head,
4292		    void *tail, void **p, int cnt, unsigned long addr)
4293{
4294	memcg_slab_free_hook(s, slab, p, cnt);
4295	/*
4296	 * With KASAN enabled slab_free_freelist_hook modifies the freelist
4297	 * to remove objects, whose reuse must be delayed.
4298	 */
4299	if (likely(slab_free_freelist_hook(s, &head, &tail, &cnt)))
4300		do_slab_free(s, slab, head, tail, cnt, addr);
4301}
4302
4303#ifdef CONFIG_KASAN_GENERIC
4304void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
4305{
4306	do_slab_free(cache, virt_to_slab(x), x, x, 1, addr);
4307}
4308#endif
4309
4310static inline struct kmem_cache *virt_to_cache(const void *obj)
4311{
4312	struct slab *slab;
4313
4314	slab = virt_to_slab(obj);
4315	if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n", __func__))
4316		return NULL;
4317	return slab->slab_cache;
4318}
4319
4320static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
4321{
4322	struct kmem_cache *cachep;
4323
4324	if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
4325	    !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
4326		return s;
4327
4328	cachep = virt_to_cache(x);
4329	if (WARN(cachep && cachep != s,
4330		 "%s: Wrong slab cache. %s but object is from %s\n",
4331		 __func__, s->name, cachep->name))
4332		print_tracking(cachep, x);
4333	return cachep;
4334}
4335
4336/**
4337 * kmem_cache_free - Deallocate an object
4338 * @s: The cache the allocation was from.
4339 * @x: The previously allocated object.
4340 *
4341 * Free an object which was previously allocated from this
4342 * cache.
4343 */
4344void kmem_cache_free(struct kmem_cache *s, void *x)
4345{
4346	s = cache_from_obj(s, x);
4347	if (!s)
4348		return;
4349	trace_kmem_cache_free(_RET_IP_, x, s);
4350	slab_free(s, virt_to_slab(x), x, _RET_IP_);
4351}
4352EXPORT_SYMBOL(kmem_cache_free);
4353
4354static void free_large_kmalloc(struct folio *folio, void *object)
4355{
4356	unsigned int order = folio_order(folio);
4357
4358	if (WARN_ON_ONCE(order == 0))
4359		pr_warn_once("object pointer: 0x%p\n", object);
4360
4361	kmemleak_free(object);
4362	kasan_kfree_large(object);
4363	kmsan_kfree_large(object);
4364
4365	lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
4366			      -(PAGE_SIZE << order));
4367	folio_put(folio);
4368}
4369
4370/**
4371 * kfree - free previously allocated memory
4372 * @object: pointer returned by kmalloc() or kmem_cache_alloc()
4373 *
4374 * If @object is NULL, no operation is performed.
4375 */
4376void kfree(const void *object)
4377{
4378	struct folio *folio;
4379	struct slab *slab;
4380	struct kmem_cache *s;
4381	void *x = (void *)object;
4382
4383	trace_kfree(_RET_IP_, object);
4384
4385	if (unlikely(ZERO_OR_NULL_PTR(object)))
4386		return;
4387
4388	folio = virt_to_folio(object);
4389	if (unlikely(!folio_test_slab(folio))) {
4390		free_large_kmalloc(folio, (void *)object);
4391		return;
4392	}
4393
4394	slab = folio_slab(folio);
4395	s = slab->slab_cache;
4396	slab_free(s, slab, x, _RET_IP_);
4397}
4398EXPORT_SYMBOL(kfree);
4399
4400struct detached_freelist {
4401	struct slab *slab;
4402	void *tail;
4403	void *freelist;
4404	int cnt;
4405	struct kmem_cache *s;
4406};
4407
 
 
 
 
 
 
 
 
 
 
4408/*
4409 * This function progressively scans the array with free objects (with
4410 * a limited look ahead) and extract objects belonging to the same
4411 * slab.  It builds a detached freelist directly within the given
4412 * slab/objects.  This can happen without any need for
4413 * synchronization, because the objects are owned by running process.
4414 * The freelist is build up as a single linked list in the objects.
4415 * The idea is, that this detached freelist can then be bulk
4416 * transferred to the real freelist(s), but only requiring a single
4417 * synchronization primitive.  Look ahead in the array is limited due
4418 * to performance reasons.
4419 */
4420static inline
4421int build_detached_freelist(struct kmem_cache *s, size_t size,
4422			    void **p, struct detached_freelist *df)
4423{
 
4424	int lookahead = 3;
4425	void *object;
4426	struct folio *folio;
4427	size_t same;
 
 
 
 
 
 
 
4428
4429	object = p[--size];
4430	folio = virt_to_folio(object);
 
 
4431	if (!s) {
4432		/* Handle kalloc'ed objects */
4433		if (unlikely(!folio_test_slab(folio))) {
4434			free_large_kmalloc(folio, object);
4435			df->slab = NULL;
4436			return size;
4437		}
4438		/* Derive kmem_cache from object */
4439		df->slab = folio_slab(folio);
4440		df->s = df->slab->slab_cache;
4441	} else {
4442		df->slab = folio_slab(folio);
4443		df->s = cache_from_obj(s, object); /* Support for memcg */
4444	}
4445
 
 
 
 
 
 
 
4446	/* Start new detached freelist */
 
 
4447	df->tail = object;
4448	df->freelist = object;
 
4449	df->cnt = 1;
4450
4451	if (is_kfence_address(object))
4452		return size;
4453
4454	set_freepointer(df->s, object, NULL);
4455
4456	same = size;
4457	while (size) {
4458		object = p[--size];
4459		/* df->slab is always set at this point */
4460		if (df->slab == virt_to_slab(object)) {
 
 
 
4461			/* Opportunity build freelist */
4462			set_freepointer(df->s, object, df->freelist);
4463			df->freelist = object;
4464			df->cnt++;
4465			same--;
4466			if (size != same)
4467				swap(p[size], p[same]);
4468			continue;
4469		}
4470
4471		/* Limit look ahead search */
4472		if (!--lookahead)
4473			break;
4474	}
4475
4476	return same;
4477}
4478
4479/*
4480 * Internal bulk free of objects that were not initialised by the post alloc
4481 * hooks and thus should not be processed by the free hooks
4482 */
4483static void __kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
4484{
4485	if (!size)
4486		return;
4487
4488	do {
4489		struct detached_freelist df;
4490
4491		size = build_detached_freelist(s, size, p, &df);
4492		if (!df.slab)
4493			continue;
4494
4495		do_slab_free(df.s, df.slab, df.freelist, df.tail, df.cnt,
4496			     _RET_IP_);
4497	} while (likely(size));
4498}
4499
4500/* Note that interrupts must be enabled when calling this function. */
4501void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
4502{
4503	if (!size)
4504		return;
4505
 
4506	do {
4507		struct detached_freelist df;
4508
4509		size = build_detached_freelist(s, size, p, &df);
4510		if (!df.slab)
4511			continue;
4512
4513		slab_free_bulk(df.s, df.slab, df.freelist, df.tail, &p[size],
4514			       df.cnt, _RET_IP_);
4515	} while (likely(size));
4516}
4517EXPORT_SYMBOL(kmem_cache_free_bulk);
4518
4519#ifndef CONFIG_SLUB_TINY
4520static inline
4521int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
4522			    void **p)
4523{
4524	struct kmem_cache_cpu *c;
4525	unsigned long irqflags;
4526	int i;
 
4527
 
 
 
 
4528	/*
4529	 * Drain objects in the per cpu slab, while disabling local
4530	 * IRQs, which protects against PREEMPT and interrupts
4531	 * handlers invoking normal fastpath.
4532	 */
4533	c = slub_get_cpu_ptr(s->cpu_slab);
4534	local_lock_irqsave(&s->cpu_slab->lock, irqflags);
4535
4536	for (i = 0; i < size; i++) {
4537		void *object = kfence_alloc(s, s->object_size, flags);
4538
4539		if (unlikely(object)) {
4540			p[i] = object;
4541			continue;
4542		}
4543
4544		object = c->freelist;
4545		if (unlikely(!object)) {
4546			/*
4547			 * We may have removed an object from c->freelist using
4548			 * the fastpath in the previous iteration; in that case,
4549			 * c->tid has not been bumped yet.
4550			 * Since ___slab_alloc() may reenable interrupts while
4551			 * allocating memory, we should bump c->tid now.
4552			 */
4553			c->tid = next_tid(c->tid);
4554
4555			local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
4556
4557			/*
4558			 * Invoking slow path likely have side-effect
4559			 * of re-populating per CPU c->freelist
4560			 */
4561			p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
4562					    _RET_IP_, c, s->object_size);
4563			if (unlikely(!p[i]))
4564				goto error;
4565
4566			c = this_cpu_ptr(s->cpu_slab);
4567			maybe_wipe_obj_freeptr(s, p[i]);
4568
4569			local_lock_irqsave(&s->cpu_slab->lock, irqflags);
4570
4571			continue; /* goto for-loop */
4572		}
4573		c->freelist = get_freepointer(s, object);
4574		p[i] = object;
4575		maybe_wipe_obj_freeptr(s, p[i]);
4576		stat(s, ALLOC_FASTPATH);
4577	}
4578	c->tid = next_tid(c->tid);
4579	local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
4580	slub_put_cpu_ptr(s->cpu_slab);
4581
4582	return i;
4583
4584error:
4585	slub_put_cpu_ptr(s->cpu_slab);
4586	__kmem_cache_free_bulk(s, i, p);
4587	return 0;
4588
4589}
4590#else /* CONFIG_SLUB_TINY */
4591static int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
4592				   size_t size, void **p)
4593{
4594	int i;
4595
4596	for (i = 0; i < size; i++) {
4597		void *object = kfence_alloc(s, s->object_size, flags);
4598
4599		if (unlikely(object)) {
4600			p[i] = object;
4601			continue;
4602		}
4603
4604		p[i] = __slab_alloc_node(s, flags, NUMA_NO_NODE,
4605					 _RET_IP_, s->object_size);
4606		if (unlikely(!p[i]))
4607			goto error;
4608
4609		maybe_wipe_obj_freeptr(s, p[i]);
4610	}
4611
4612	return i;
4613
4614error:
4615	__kmem_cache_free_bulk(s, i, p);
4616	return 0;
4617}
4618#endif /* CONFIG_SLUB_TINY */
4619
4620/* Note that interrupts must be enabled when calling this function. */
4621int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
4622			  void **p)
4623{
4624	int i;
4625	struct obj_cgroup *objcg = NULL;
4626
4627	if (!size)
4628		return 0;
4629
4630	/* memcg and kmem_cache debug support */
4631	s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags);
4632	if (unlikely(!s))
4633		return 0;
4634
4635	i = __kmem_cache_alloc_bulk(s, flags, size, p);
4636
4637	/*
4638	 * memcg and kmem_cache debug support and memory initialization.
4639	 * Done outside of the IRQ disabled fastpath loop.
4640	 */
4641	if (likely(i != 0)) {
4642		slab_post_alloc_hook(s, objcg, flags, size, p,
4643			slab_want_init_on_alloc(flags, s), s->object_size);
4644	} else {
4645		memcg_slab_alloc_error_hook(s, size, objcg);
4646	}
4647
4648	return i;
 
 
 
 
 
4649}
4650EXPORT_SYMBOL(kmem_cache_alloc_bulk);
4651
4652
4653/*
4654 * Object placement in a slab is made very easy because we always start at
4655 * offset 0. If we tune the size of the object to the alignment then we can
4656 * get the required alignment by putting one properly sized object after
4657 * another.
4658 *
4659 * Notice that the allocation order determines the sizes of the per cpu
4660 * caches. Each processor has always one slab available for allocations.
4661 * Increasing the allocation order reduces the number of times that slabs
4662 * must be moved on and off the partial lists and is therefore a factor in
4663 * locking overhead.
4664 */
4665
4666/*
4667 * Minimum / Maximum order of slab pages. This influences locking overhead
4668 * and slab fragmentation. A higher order reduces the number of partial slabs
4669 * and increases the number of allocations possible without having to
4670 * take the list_lock.
4671 */
4672static unsigned int slub_min_order;
4673static unsigned int slub_max_order =
4674	IS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER;
4675static unsigned int slub_min_objects;
4676
4677/*
4678 * Calculate the order of allocation given an slab object size.
4679 *
4680 * The order of allocation has significant impact on performance and other
4681 * system components. Generally order 0 allocations should be preferred since
4682 * order 0 does not cause fragmentation in the page allocator. Larger objects
4683 * be problematic to put into order 0 slabs because there may be too much
4684 * unused space left. We go to a higher order if more than 1/16th of the slab
4685 * would be wasted.
4686 *
4687 * In order to reach satisfactory performance we must ensure that a minimum
4688 * number of objects is in one slab. Otherwise we may generate too much
4689 * activity on the partial lists which requires taking the list_lock. This is
4690 * less a concern for large slabs though which are rarely used.
4691 *
4692 * slab_max_order specifies the order where we begin to stop considering the
4693 * number of objects in a slab as critical. If we reach slab_max_order then
4694 * we try to keep the page order as low as possible. So we accept more waste
4695 * of space in favor of a small page order.
4696 *
4697 * Higher order allocations also allow the placement of more objects in a
4698 * slab and thereby reduce object handling overhead. If the user has
4699 * requested a higher minimum order then we start with that one instead of
4700 * the smallest order which will fit the object.
4701 */
4702static inline unsigned int calc_slab_order(unsigned int size,
4703		unsigned int min_order, unsigned int max_order,
4704		unsigned int fract_leftover)
4705{
 
4706	unsigned int order;
4707
4708	for (order = min_order; order <= max_order; order++) {
 
 
 
 
4709
4710		unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
4711		unsigned int rem;
4712
4713		rem = slab_size % size;
4714
4715		if (rem <= slab_size / fract_leftover)
4716			break;
4717	}
4718
4719	return order;
4720}
4721
4722static inline int calculate_order(unsigned int size)
4723{
4724	unsigned int order;
4725	unsigned int min_objects;
4726	unsigned int max_objects;
4727	unsigned int min_order;
4728
 
 
 
 
 
 
 
 
4729	min_objects = slub_min_objects;
4730	if (!min_objects) {
4731		/*
4732		 * Some architectures will only update present cpus when
4733		 * onlining them, so don't trust the number if it's just 1. But
4734		 * we also don't want to use nr_cpu_ids always, as on some other
4735		 * architectures, there can be many possible cpus, but never
4736		 * onlined. Here we compromise between trying to avoid too high
4737		 * order on systems that appear larger than they are, and too
4738		 * low order on systems that appear smaller than they are.
4739		 */
4740		unsigned int nr_cpus = num_present_cpus();
4741		if (nr_cpus <= 1)
4742			nr_cpus = nr_cpu_ids;
4743		min_objects = 4 * (fls(nr_cpus) + 1);
4744	}
4745	/* min_objects can't be 0 because get_order(0) is undefined */
4746	max_objects = max(order_objects(slub_max_order, size), 1U);
4747	min_objects = min(min_objects, max_objects);
4748
4749	min_order = max_t(unsigned int, slub_min_order,
4750			  get_order(min_objects * size));
4751	if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
4752		return get_order(size * MAX_OBJS_PER_PAGE) - 1;
 
 
 
 
 
 
 
 
 
4753
4754	/*
4755	 * Attempt to find best configuration for a slab. This works by first
4756	 * attempting to generate a layout with the best possible configuration
4757	 * and backing off gradually.
4758	 *
4759	 * We start with accepting at most 1/16 waste and try to find the
4760	 * smallest order from min_objects-derived/slab_min_order up to
4761	 * slab_max_order that will satisfy the constraint. Note that increasing
4762	 * the order can only result in same or less fractional waste, not more.
4763	 *
4764	 * If that fails, we increase the acceptable fraction of waste and try
4765	 * again. The last iteration with fraction of 1/2 would effectively
4766	 * accept any waste and give us the order determined by min_objects, as
4767	 * long as at least single object fits within slab_max_order.
4768	 */
4769	for (unsigned int fraction = 16; fraction > 1; fraction /= 2) {
4770		order = calc_slab_order(size, min_order, slub_max_order,
4771					fraction);
4772		if (order <= slub_max_order)
4773			return order;
4774	}
4775
4776	/*
4777	 * Doh this slab cannot be placed using slab_max_order.
4778	 */
4779	order = get_order(size);
4780	if (order <= MAX_PAGE_ORDER)
4781		return order;
4782	return -ENOSYS;
4783}
4784
4785static void
4786init_kmem_cache_node(struct kmem_cache_node *n)
4787{
4788	n->nr_partial = 0;
4789	spin_lock_init(&n->list_lock);
4790	INIT_LIST_HEAD(&n->partial);
4791#ifdef CONFIG_SLUB_DEBUG
4792	atomic_long_set(&n->nr_slabs, 0);
4793	atomic_long_set(&n->total_objects, 0);
4794	INIT_LIST_HEAD(&n->full);
4795#endif
4796}
4797
4798#ifndef CONFIG_SLUB_TINY
4799static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
4800{
4801	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
4802			NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
4803			sizeof(struct kmem_cache_cpu));
4804
4805	/*
4806	 * Must align to double word boundary for the double cmpxchg
4807	 * instructions to work; see __pcpu_double_call_return_bool().
4808	 */
4809	s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
4810				     2 * sizeof(void *));
4811
4812	if (!s->cpu_slab)
4813		return 0;
4814
4815	init_kmem_cache_cpus(s);
4816
4817	return 1;
4818}
4819#else
4820static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
4821{
4822	return 1;
4823}
4824#endif /* CONFIG_SLUB_TINY */
4825
4826static struct kmem_cache *kmem_cache_node;
4827
4828/*
4829 * No kmalloc_node yet so do it by hand. We know that this is the first
4830 * slab on the node for this slabcache. There are no concurrent accesses
4831 * possible.
4832 *
4833 * Note that this function only works on the kmem_cache_node
4834 * when allocating for the kmem_cache_node. This is used for bootstrapping
4835 * memory on a fresh node that has no slab structures yet.
4836 */
4837static void early_kmem_cache_node_alloc(int node)
4838{
4839	struct slab *slab;
4840	struct kmem_cache_node *n;
4841
4842	BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
4843
4844	slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
4845
4846	BUG_ON(!slab);
4847	if (slab_nid(slab) != node) {
4848		pr_err("SLUB: Unable to allocate memory from node %d\n", node);
4849		pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
4850	}
4851
4852	n = slab->freelist;
4853	BUG_ON(!n);
4854#ifdef CONFIG_SLUB_DEBUG
4855	init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
4856	init_tracking(kmem_cache_node, n);
4857#endif
4858	n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
4859	slab->freelist = get_freepointer(kmem_cache_node, n);
4860	slab->inuse = 1;
 
4861	kmem_cache_node->node[node] = n;
4862	init_kmem_cache_node(n);
4863	inc_slabs_node(kmem_cache_node, node, slab->objects);
4864
4865	/*
4866	 * No locks need to be taken here as it has just been
4867	 * initialized and there is no concurrent access.
4868	 */
4869	__add_partial(n, slab, DEACTIVATE_TO_HEAD);
4870}
4871
4872static void free_kmem_cache_nodes(struct kmem_cache *s)
4873{
4874	int node;
4875	struct kmem_cache_node *n;
4876
4877	for_each_kmem_cache_node(s, node, n) {
4878		s->node[node] = NULL;
4879		kmem_cache_free(kmem_cache_node, n);
4880	}
4881}
4882
4883void __kmem_cache_release(struct kmem_cache *s)
4884{
4885	cache_random_seq_destroy(s);
4886#ifndef CONFIG_SLUB_TINY
4887	free_percpu(s->cpu_slab);
4888#endif
4889	free_kmem_cache_nodes(s);
4890}
4891
4892static int init_kmem_cache_nodes(struct kmem_cache *s)
4893{
4894	int node;
4895
4896	for_each_node_mask(node, slab_nodes) {
4897		struct kmem_cache_node *n;
4898
4899		if (slab_state == DOWN) {
4900			early_kmem_cache_node_alloc(node);
4901			continue;
4902		}
4903		n = kmem_cache_alloc_node(kmem_cache_node,
4904						GFP_KERNEL, node);
4905
4906		if (!n) {
4907			free_kmem_cache_nodes(s);
4908			return 0;
4909		}
4910
4911		init_kmem_cache_node(n);
4912		s->node[node] = n;
4913	}
4914	return 1;
4915}
4916
 
 
 
 
 
 
 
 
 
4917static void set_cpu_partial(struct kmem_cache *s)
4918{
4919#ifdef CONFIG_SLUB_CPU_PARTIAL
4920	unsigned int nr_objects;
4921
4922	/*
4923	 * cpu_partial determined the maximum number of objects kept in the
4924	 * per cpu partial lists of a processor.
4925	 *
4926	 * Per cpu partial lists mainly contain slabs that just have one
4927	 * object freed. If they are used for allocation then they can be
4928	 * filled up again with minimal effort. The slab will never hit the
4929	 * per node partial lists and therefore no locking will be required.
4930	 *
4931	 * For backwards compatibility reasons, this is determined as number
4932	 * of objects, even though we now limit maximum number of pages, see
4933	 * slub_set_cpu_partial()
 
 
 
 
4934	 */
4935	if (!kmem_cache_has_cpu_partial(s))
4936		nr_objects = 0;
4937	else if (s->size >= PAGE_SIZE)
4938		nr_objects = 6;
4939	else if (s->size >= 1024)
4940		nr_objects = 24;
4941	else if (s->size >= 256)
4942		nr_objects = 52;
4943	else
4944		nr_objects = 120;
4945
4946	slub_set_cpu_partial(s, nr_objects);
4947#endif
4948}
4949
4950/*
4951 * calculate_sizes() determines the order and the distribution of data within
4952 * a slab object.
4953 */
4954static int calculate_sizes(struct kmem_cache *s)
4955{
4956	slab_flags_t flags = s->flags;
4957	unsigned int size = s->object_size;
4958	unsigned int order;
4959
4960	/*
4961	 * Round up object size to the next word boundary. We can only
4962	 * place the free pointer at word boundaries and this determines
4963	 * the possible location of the free pointer.
4964	 */
4965	size = ALIGN(size, sizeof(void *));
4966
4967#ifdef CONFIG_SLUB_DEBUG
4968	/*
4969	 * Determine if we can poison the object itself. If the user of
4970	 * the slab may touch the object after free or before allocation
4971	 * then we should never poison the object itself.
4972	 */
4973	if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
4974			!s->ctor)
4975		s->flags |= __OBJECT_POISON;
4976	else
4977		s->flags &= ~__OBJECT_POISON;
4978
4979
4980	/*
4981	 * If we are Redzoning then check if there is some space between the
4982	 * end of the object and the free pointer. If not then add an
4983	 * additional word to have some bytes to store Redzone information.
4984	 */
4985	if ((flags & SLAB_RED_ZONE) && size == s->object_size)
4986		size += sizeof(void *);
4987#endif
4988
4989	/*
4990	 * With that we have determined the number of bytes in actual use
4991	 * by the object and redzoning.
4992	 */
4993	s->inuse = size;
4994
4995	if (slub_debug_orig_size(s) ||
4996	    (flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
4997	    ((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) ||
4998	    s->ctor) {
4999		/*
5000		 * Relocate free pointer after the object if it is not
5001		 * permitted to overwrite the first word of the object on
5002		 * kmem_cache_free.
5003		 *
5004		 * This is the case if we do RCU, have a constructor or
5005		 * destructor, are poisoning the objects, or are
5006		 * redzoning an object smaller than sizeof(void *).
5007		 *
5008		 * The assumption that s->offset >= s->inuse means free
5009		 * pointer is outside of the object is used in the
5010		 * freeptr_outside_object() function. If that is no
5011		 * longer true, the function needs to be modified.
5012		 */
5013		s->offset = size;
5014		size += sizeof(void *);
5015	} else {
5016		/*
5017		 * Store freelist pointer near middle of object to keep
5018		 * it away from the edges of the object to avoid small
5019		 * sized over/underflows from neighboring allocations.
5020		 */
5021		s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *));
5022	}
5023
5024#ifdef CONFIG_SLUB_DEBUG
5025	if (flags & SLAB_STORE_USER) {
5026		/*
5027		 * Need to store information about allocs and frees after
5028		 * the object.
5029		 */
5030		size += 2 * sizeof(struct track);
5031
5032		/* Save the original kmalloc request size */
5033		if (flags & SLAB_KMALLOC)
5034			size += sizeof(unsigned int);
5035	}
5036#endif
5037
5038	kasan_cache_create(s, &size, &s->flags);
5039#ifdef CONFIG_SLUB_DEBUG
5040	if (flags & SLAB_RED_ZONE) {
5041		/*
5042		 * Add some empty padding so that we can catch
5043		 * overwrites from earlier objects rather than let
5044		 * tracking information or the free pointer be
5045		 * corrupted if a user writes before the start
5046		 * of the object.
5047		 */
5048		size += sizeof(void *);
5049
5050		s->red_left_pad = sizeof(void *);
5051		s->red_left_pad = ALIGN(s->red_left_pad, s->align);
5052		size += s->red_left_pad;
5053	}
5054#endif
5055
5056	/*
5057	 * SLUB stores one object immediately after another beginning from
5058	 * offset 0. In order to align the objects we have to simply size
5059	 * each object to conform to the alignment.
5060	 */
5061	size = ALIGN(size, s->align);
5062	s->size = size;
5063	s->reciprocal_size = reciprocal_value(size);
5064	order = calculate_order(size);
 
 
 
5065
5066	if ((int)order < 0)
5067		return 0;
5068
5069	s->allocflags = 0;
5070	if (order)
5071		s->allocflags |= __GFP_COMP;
5072
5073	if (s->flags & SLAB_CACHE_DMA)
5074		s->allocflags |= GFP_DMA;
5075
5076	if (s->flags & SLAB_CACHE_DMA32)
5077		s->allocflags |= GFP_DMA32;
5078
5079	if (s->flags & SLAB_RECLAIM_ACCOUNT)
5080		s->allocflags |= __GFP_RECLAIMABLE;
5081
5082	/*
5083	 * Determine the number of objects per slab
5084	 */
5085	s->oo = oo_make(order, size);
5086	s->min = oo_make(get_order(size), size);
 
 
5087
5088	return !!oo_objects(s->oo);
5089}
5090
5091static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
5092{
5093	s->flags = kmem_cache_flags(flags, s->name);
5094#ifdef CONFIG_SLAB_FREELIST_HARDENED
5095	s->random = get_random_long();
5096#endif
5097
5098	if (!calculate_sizes(s))
5099		goto error;
5100	if (disable_higher_order_debug) {
5101		/*
5102		 * Disable debugging flags that store metadata if the min slab
5103		 * order increased.
5104		 */
5105		if (get_order(s->size) > get_order(s->object_size)) {
5106			s->flags &= ~DEBUG_METADATA_FLAGS;
5107			s->offset = 0;
5108			if (!calculate_sizes(s))
5109				goto error;
5110		}
5111	}
5112
5113#ifdef system_has_freelist_aba
5114	if (system_has_freelist_aba() && !(s->flags & SLAB_NO_CMPXCHG)) {
 
5115		/* Enable fast mode */
5116		s->flags |= __CMPXCHG_DOUBLE;
5117	}
5118#endif
5119
5120	/*
5121	 * The larger the object size is, the more slabs we want on the partial
5122	 * list to avoid pounding the page allocator excessively.
5123	 */
5124	s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
5125	s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
5126
5127	set_cpu_partial(s);
5128
5129#ifdef CONFIG_NUMA
5130	s->remote_node_defrag_ratio = 1000;
5131#endif
5132
5133	/* Initialize the pre-computed randomized freelist if slab is up */
5134	if (slab_state >= UP) {
5135		if (init_cache_random_seq(s))
5136			goto error;
5137	}
5138
5139	if (!init_kmem_cache_nodes(s))
5140		goto error;
5141
5142	if (alloc_kmem_cache_cpus(s))
5143		return 0;
5144
5145error:
5146	__kmem_cache_release(s);
5147	return -EINVAL;
5148}
5149
5150static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
5151			      const char *text)
5152{
5153#ifdef CONFIG_SLUB_DEBUG
5154	void *addr = slab_address(slab);
 
5155	void *p;
5156
5157	slab_err(s, slab, text, s->name);
5158
5159	spin_lock(&object_map_lock);
5160	__fill_map(object_map, s, slab);
5161
5162	for_each_object(p, s, addr, slab->objects) {
 
5163
5164		if (!test_bit(__obj_to_index(s, addr, p), object_map)) {
5165			pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
5166			print_tracking(s, p);
5167		}
5168	}
5169	spin_unlock(&object_map_lock);
 
5170#endif
5171}
5172
5173/*
5174 * Attempt to free all partial slabs on a node.
5175 * This is called from __kmem_cache_shutdown(). We must take list_lock
5176 * because sysfs file might still access partial list after the shutdowning.
5177 */
5178static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
5179{
5180	LIST_HEAD(discard);
5181	struct slab *slab, *h;
5182
5183	BUG_ON(irqs_disabled());
5184	spin_lock_irq(&n->list_lock);
5185	list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
5186		if (!slab->inuse) {
5187			remove_partial(n, slab);
5188			list_add(&slab->slab_list, &discard);
5189		} else {
5190			list_slab_objects(s, slab,
5191			  "Objects remaining in %s on __kmem_cache_shutdown()");
5192		}
5193	}
5194	spin_unlock_irq(&n->list_lock);
5195
5196	list_for_each_entry_safe(slab, h, &discard, slab_list)
5197		discard_slab(s, slab);
5198}
5199
5200bool __kmem_cache_empty(struct kmem_cache *s)
5201{
5202	int node;
5203	struct kmem_cache_node *n;
5204
5205	for_each_kmem_cache_node(s, node, n)
5206		if (n->nr_partial || node_nr_slabs(n))
5207			return false;
5208	return true;
5209}
5210
5211/*
5212 * Release all resources used by a slab cache.
5213 */
5214int __kmem_cache_shutdown(struct kmem_cache *s)
5215{
5216	int node;
5217	struct kmem_cache_node *n;
5218
5219	flush_all_cpus_locked(s);
5220	/* Attempt to free all objects */
5221	for_each_kmem_cache_node(s, node, n) {
5222		free_partial(s, n);
5223		if (n->nr_partial || node_nr_slabs(n))
5224			return 1;
5225	}
5226	return 0;
5227}
5228
5229#ifdef CONFIG_PRINTK
5230void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
5231{
5232	void *base;
5233	int __maybe_unused i;
5234	unsigned int objnr;
5235	void *objp;
5236	void *objp0;
5237	struct kmem_cache *s = slab->slab_cache;
5238	struct track __maybe_unused *trackp;
5239
5240	kpp->kp_ptr = object;
5241	kpp->kp_slab = slab;
5242	kpp->kp_slab_cache = s;
5243	base = slab_address(slab);
5244	objp0 = kasan_reset_tag(object);
5245#ifdef CONFIG_SLUB_DEBUG
5246	objp = restore_red_left(s, objp0);
5247#else
5248	objp = objp0;
5249#endif
5250	objnr = obj_to_index(s, slab, objp);
5251	kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
5252	objp = base + s->size * objnr;
5253	kpp->kp_objp = objp;
5254	if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
5255			 || (objp - base) % s->size) ||
5256	    !(s->flags & SLAB_STORE_USER))
5257		return;
5258#ifdef CONFIG_SLUB_DEBUG
5259	objp = fixup_red_left(s, objp);
5260	trackp = get_track(s, objp, TRACK_ALLOC);
5261	kpp->kp_ret = (void *)trackp->addr;
5262#ifdef CONFIG_STACKDEPOT
5263	{
5264		depot_stack_handle_t handle;
5265		unsigned long *entries;
5266		unsigned int nr_entries;
5267
5268		handle = READ_ONCE(trackp->handle);
5269		if (handle) {
5270			nr_entries = stack_depot_fetch(handle, &entries);
5271			for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
5272				kpp->kp_stack[i] = (void *)entries[i];
5273		}
5274
5275		trackp = get_track(s, objp, TRACK_FREE);
5276		handle = READ_ONCE(trackp->handle);
5277		if (handle) {
5278			nr_entries = stack_depot_fetch(handle, &entries);
5279			for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
5280				kpp->kp_free_stack[i] = (void *)entries[i];
5281		}
5282	}
5283#endif
5284#endif
5285}
5286#endif
5287
5288/********************************************************************
5289 *		Kmalloc subsystem
5290 *******************************************************************/
5291
5292static int __init setup_slub_min_order(char *str)
5293{
5294	get_option(&str, (int *)&slub_min_order);
5295
5296	if (slub_min_order > slub_max_order)
5297		slub_max_order = slub_min_order;
5298
5299	return 1;
5300}
5301
5302__setup("slab_min_order=", setup_slub_min_order);
5303__setup_param("slub_min_order=", slub_min_order, setup_slub_min_order, 0);
5304
5305
5306static int __init setup_slub_max_order(char *str)
5307{
5308	get_option(&str, (int *)&slub_max_order);
5309	slub_max_order = min_t(unsigned int, slub_max_order, MAX_PAGE_ORDER);
5310
5311	if (slub_min_order > slub_max_order)
5312		slub_min_order = slub_max_order;
5313
5314	return 1;
5315}
5316
5317__setup("slab_max_order=", setup_slub_max_order);
5318__setup_param("slub_max_order=", slub_max_order, setup_slub_max_order, 0);
5319
5320static int __init setup_slub_min_objects(char *str)
5321{
5322	get_option(&str, (int *)&slub_min_objects);
5323
5324	return 1;
5325}
5326
5327__setup("slab_min_objects=", setup_slub_min_objects);
5328__setup_param("slub_min_objects=", slub_min_objects, setup_slub_min_objects, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5329
5330#ifdef CONFIG_HARDENED_USERCOPY
5331/*
5332 * Rejects incorrectly sized objects and objects that are to be copied
5333 * to/from userspace but do not fall entirely within the containing slab
5334 * cache's usercopy region.
5335 *
5336 * Returns NULL if check passes, otherwise const char * to name of cache
5337 * to indicate an error.
5338 */
5339void __check_heap_object(const void *ptr, unsigned long n,
5340			 const struct slab *slab, bool to_user)
5341{
5342	struct kmem_cache *s;
5343	unsigned int offset;
 
5344	bool is_kfence = is_kfence_address(ptr);
5345
5346	ptr = kasan_reset_tag(ptr);
5347
5348	/* Find object and usable object size. */
5349	s = slab->slab_cache;
5350
5351	/* Reject impossible pointers. */
5352	if (ptr < slab_address(slab))
5353		usercopy_abort("SLUB object not in SLUB page?!", NULL,
5354			       to_user, 0, n);
5355
5356	/* Find offset within object. */
5357	if (is_kfence)
5358		offset = ptr - kfence_object_start(ptr);
5359	else
5360		offset = (ptr - slab_address(slab)) % s->size;
5361
5362	/* Adjust for redzone and reject if within the redzone. */
5363	if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
5364		if (offset < s->red_left_pad)
5365			usercopy_abort("SLUB object in left red zone",
5366				       s->name, to_user, offset, n);
5367		offset -= s->red_left_pad;
5368	}
5369
5370	/* Allow address range falling entirely within usercopy region. */
5371	if (offset >= s->useroffset &&
5372	    offset - s->useroffset <= s->usersize &&
5373	    n <= s->useroffset - offset + s->usersize)
5374		return;
5375
 
 
 
 
 
 
 
 
 
 
 
 
 
5376	usercopy_abort("SLUB object", s->name, to_user, offset, n);
5377}
5378#endif /* CONFIG_HARDENED_USERCOPY */
5379
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5380#define SHRINK_PROMOTE_MAX 32
5381
5382/*
5383 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
5384 * up most to the head of the partial lists. New allocations will then
5385 * fill those up and thus they can be removed from the partial lists.
5386 *
5387 * The slabs with the least items are placed last. This results in them
5388 * being allocated from last increasing the chance that the last objects
5389 * are freed in them.
5390 */
5391static int __kmem_cache_do_shrink(struct kmem_cache *s)
5392{
5393	int node;
5394	int i;
5395	struct kmem_cache_node *n;
5396	struct slab *slab;
5397	struct slab *t;
5398	struct list_head discard;
5399	struct list_head promote[SHRINK_PROMOTE_MAX];
5400	unsigned long flags;
5401	int ret = 0;
5402
 
5403	for_each_kmem_cache_node(s, node, n) {
5404		INIT_LIST_HEAD(&discard);
5405		for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
5406			INIT_LIST_HEAD(promote + i);
5407
5408		spin_lock_irqsave(&n->list_lock, flags);
5409
5410		/*
5411		 * Build lists of slabs to discard or promote.
5412		 *
5413		 * Note that concurrent frees may occur while we hold the
5414		 * list_lock. slab->inuse here is the upper limit.
5415		 */
5416		list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
5417			int free = slab->objects - slab->inuse;
5418
5419			/* Do not reread slab->inuse */
5420			barrier();
5421
5422			/* We do not keep full slabs on the list */
5423			BUG_ON(free <= 0);
5424
5425			if (free == slab->objects) {
5426				list_move(&slab->slab_list, &discard);
5427				slab_clear_node_partial(slab);
5428				n->nr_partial--;
5429				dec_slabs_node(s, node, slab->objects);
5430			} else if (free <= SHRINK_PROMOTE_MAX)
5431				list_move(&slab->slab_list, promote + free - 1);
5432		}
5433
5434		/*
5435		 * Promote the slabs filled up most to the head of the
5436		 * partial list.
5437		 */
5438		for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
5439			list_splice(promote + i, &n->partial);
5440
5441		spin_unlock_irqrestore(&n->list_lock, flags);
5442
5443		/* Release empty slabs */
5444		list_for_each_entry_safe(slab, t, &discard, slab_list)
5445			free_slab(s, slab);
5446
5447		if (node_nr_slabs(n))
5448			ret = 1;
5449	}
5450
5451	return ret;
5452}
5453
5454int __kmem_cache_shrink(struct kmem_cache *s)
5455{
5456	flush_all(s);
5457	return __kmem_cache_do_shrink(s);
5458}
5459
5460static int slab_mem_going_offline_callback(void *arg)
5461{
5462	struct kmem_cache *s;
5463
5464	mutex_lock(&slab_mutex);
5465	list_for_each_entry(s, &slab_caches, list) {
5466		flush_all_cpus_locked(s);
5467		__kmem_cache_do_shrink(s);
5468	}
5469	mutex_unlock(&slab_mutex);
5470
5471	return 0;
5472}
5473
5474static void slab_mem_offline_callback(void *arg)
5475{
5476	struct memory_notify *marg = arg;
5477	int offline_node;
5478
5479	offline_node = marg->status_change_nid_normal;
5480
5481	/*
5482	 * If the node still has available memory. we need kmem_cache_node
5483	 * for it yet.
5484	 */
5485	if (offline_node < 0)
5486		return;
5487
5488	mutex_lock(&slab_mutex);
5489	node_clear(offline_node, slab_nodes);
5490	/*
5491	 * We no longer free kmem_cache_node structures here, as it would be
5492	 * racy with all get_node() users, and infeasible to protect them with
5493	 * slab_mutex.
5494	 */
5495	mutex_unlock(&slab_mutex);
5496}
5497
5498static int slab_mem_going_online_callback(void *arg)
5499{
5500	struct kmem_cache_node *n;
5501	struct kmem_cache *s;
5502	struct memory_notify *marg = arg;
5503	int nid = marg->status_change_nid_normal;
5504	int ret = 0;
5505
5506	/*
5507	 * If the node's memory is already available, then kmem_cache_node is
5508	 * already created. Nothing to do.
5509	 */
5510	if (nid < 0)
5511		return 0;
5512
5513	/*
5514	 * We are bringing a node online. No memory is available yet. We must
5515	 * allocate a kmem_cache_node structure in order to bring the node
5516	 * online.
5517	 */
5518	mutex_lock(&slab_mutex);
5519	list_for_each_entry(s, &slab_caches, list) {
5520		/*
5521		 * The structure may already exist if the node was previously
5522		 * onlined and offlined.
5523		 */
5524		if (get_node(s, nid))
5525			continue;
5526		/*
5527		 * XXX: kmem_cache_alloc_node will fallback to other nodes
5528		 *      since memory is not yet available from the node that
5529		 *      is brought up.
5530		 */
5531		n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
5532		if (!n) {
5533			ret = -ENOMEM;
5534			goto out;
5535		}
5536		init_kmem_cache_node(n);
5537		s->node[nid] = n;
5538	}
5539	/*
5540	 * Any cache created after this point will also have kmem_cache_node
5541	 * initialized for the new node.
5542	 */
5543	node_set(nid, slab_nodes);
5544out:
5545	mutex_unlock(&slab_mutex);
5546	return ret;
5547}
5548
5549static int slab_memory_callback(struct notifier_block *self,
5550				unsigned long action, void *arg)
5551{
5552	int ret = 0;
5553
5554	switch (action) {
5555	case MEM_GOING_ONLINE:
5556		ret = slab_mem_going_online_callback(arg);
5557		break;
5558	case MEM_GOING_OFFLINE:
5559		ret = slab_mem_going_offline_callback(arg);
5560		break;
5561	case MEM_OFFLINE:
5562	case MEM_CANCEL_ONLINE:
5563		slab_mem_offline_callback(arg);
5564		break;
5565	case MEM_ONLINE:
5566	case MEM_CANCEL_OFFLINE:
5567		break;
5568	}
5569	if (ret)
5570		ret = notifier_from_errno(ret);
5571	else
5572		ret = NOTIFY_OK;
5573	return ret;
5574}
5575
 
 
 
 
 
5576/********************************************************************
5577 *			Basic setup of slabs
5578 *******************************************************************/
5579
5580/*
5581 * Used for early kmem_cache structures that were allocated using
5582 * the page allocator. Allocate them properly then fix up the pointers
5583 * that may be pointing to the wrong kmem_cache structure.
5584 */
5585
5586static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
5587{
5588	int node;
5589	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
5590	struct kmem_cache_node *n;
5591
5592	memcpy(s, static_cache, kmem_cache->object_size);
5593
5594	/*
5595	 * This runs very early, and only the boot processor is supposed to be
5596	 * up.  Even if it weren't true, IRQs are not up so we couldn't fire
5597	 * IPIs around.
5598	 */
5599	__flush_cpu_slab(s, smp_processor_id());
5600	for_each_kmem_cache_node(s, node, n) {
5601		struct slab *p;
5602
5603		list_for_each_entry(p, &n->partial, slab_list)
5604			p->slab_cache = s;
5605
5606#ifdef CONFIG_SLUB_DEBUG
5607		list_for_each_entry(p, &n->full, slab_list)
5608			p->slab_cache = s;
5609#endif
5610	}
5611	list_add(&s->list, &slab_caches);
5612	return s;
5613}
5614
5615void __init kmem_cache_init(void)
5616{
5617	static __initdata struct kmem_cache boot_kmem_cache,
5618		boot_kmem_cache_node;
5619	int node;
5620
5621	if (debug_guardpage_minorder())
5622		slub_max_order = 0;
5623
5624	/* Print slub debugging pointers without hashing */
5625	if (__slub_debug_enabled())
5626		no_hash_pointers_enable(NULL);
5627
5628	kmem_cache_node = &boot_kmem_cache_node;
5629	kmem_cache = &boot_kmem_cache;
5630
5631	/*
5632	 * Initialize the nodemask for which we will allocate per node
5633	 * structures. Here we don't need taking slab_mutex yet.
5634	 */
5635	for_each_node_state(node, N_NORMAL_MEMORY)
5636		node_set(node, slab_nodes);
5637
5638	create_boot_cache(kmem_cache_node, "kmem_cache_node",
5639		sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
5640
5641	hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
5642
5643	/* Able to allocate the per node structures */
5644	slab_state = PARTIAL;
5645
5646	create_boot_cache(kmem_cache, "kmem_cache",
5647			offsetof(struct kmem_cache, node) +
5648				nr_node_ids * sizeof(struct kmem_cache_node *),
5649		       SLAB_HWCACHE_ALIGN, 0, 0);
5650
5651	kmem_cache = bootstrap(&boot_kmem_cache);
5652	kmem_cache_node = bootstrap(&boot_kmem_cache_node);
5653
5654	/* Now we can use the kmem_cache to allocate kmalloc slabs */
5655	setup_kmalloc_cache_index_table();
5656	create_kmalloc_caches();
5657
5658	/* Setup random freelists for each cache */
5659	init_freelist_randomization();
5660
5661	cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
5662				  slub_cpu_dead);
5663
5664	pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
5665		cache_line_size(),
5666		slub_min_order, slub_max_order, slub_min_objects,
5667		nr_cpu_ids, nr_node_ids);
5668}
5669
5670void __init kmem_cache_init_late(void)
5671{
5672#ifndef CONFIG_SLUB_TINY
5673	flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
5674	WARN_ON(!flushwq);
5675#endif
5676}
5677
5678struct kmem_cache *
5679__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
5680		   slab_flags_t flags, void (*ctor)(void *))
5681{
5682	struct kmem_cache *s;
5683
5684	s = find_mergeable(size, align, flags, name, ctor);
5685	if (s) {
5686		if (sysfs_slab_alias(s, name))
5687			return NULL;
5688
5689		s->refcount++;
5690
5691		/*
5692		 * Adjust the object sizes so that we clear
5693		 * the complete object on kzalloc.
5694		 */
5695		s->object_size = max(s->object_size, size);
5696		s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
 
 
 
 
 
5697	}
5698
5699	return s;
5700}
5701
5702int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
5703{
5704	int err;
5705
5706	err = kmem_cache_open(s, flags);
5707	if (err)
5708		return err;
5709
5710	/* Mutex is not taken during early boot */
5711	if (slab_state <= UP)
5712		return 0;
5713
5714	err = sysfs_slab_add(s);
5715	if (err) {
5716		__kmem_cache_release(s);
5717		return err;
5718	}
5719
5720	if (s->flags & SLAB_STORE_USER)
5721		debugfs_slab_add(s);
5722
5723	return 0;
5724}
5725
5726#ifdef SLAB_SUPPORTS_SYSFS
5727static int count_inuse(struct slab *slab)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5728{
5729	return slab->inuse;
5730}
5731
5732static int count_total(struct slab *slab)
5733{
5734	return slab->objects;
5735}
5736#endif
5737
5738#ifdef CONFIG_SLUB_DEBUG
5739static void validate_slab(struct kmem_cache *s, struct slab *slab,
5740			  unsigned long *obj_map)
5741{
5742	void *p;
5743	void *addr = slab_address(slab);
 
5744
5745	if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
5746		return;
 
 
5747
5748	/* Now we know that a valid freelist exists */
5749	__fill_map(obj_map, s, slab);
5750	for_each_object(p, s, addr, slab->objects) {
5751		u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
5752			 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
5753
5754		if (!check_object(s, slab, p, val))
5755			break;
5756	}
 
 
 
5757}
5758
5759static int validate_slab_node(struct kmem_cache *s,
5760		struct kmem_cache_node *n, unsigned long *obj_map)
5761{
5762	unsigned long count = 0;
5763	struct slab *slab;
5764	unsigned long flags;
5765
5766	spin_lock_irqsave(&n->list_lock, flags);
5767
5768	list_for_each_entry(slab, &n->partial, slab_list) {
5769		validate_slab(s, slab, obj_map);
5770		count++;
5771	}
5772	if (count != n->nr_partial) {
5773		pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
5774		       s->name, count, n->nr_partial);
5775		slab_add_kunit_errors();
5776	}
5777
5778	if (!(s->flags & SLAB_STORE_USER))
5779		goto out;
5780
5781	list_for_each_entry(slab, &n->full, slab_list) {
5782		validate_slab(s, slab, obj_map);
5783		count++;
5784	}
5785	if (count != node_nr_slabs(n)) {
5786		pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
5787		       s->name, count, node_nr_slabs(n));
5788		slab_add_kunit_errors();
5789	}
5790
5791out:
5792	spin_unlock_irqrestore(&n->list_lock, flags);
5793	return count;
5794}
5795
5796long validate_slab_cache(struct kmem_cache *s)
5797{
5798	int node;
5799	unsigned long count = 0;
5800	struct kmem_cache_node *n;
5801	unsigned long *obj_map;
5802
5803	obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
5804	if (!obj_map)
5805		return -ENOMEM;
5806
5807	flush_all(s);
5808	for_each_kmem_cache_node(s, node, n)
5809		count += validate_slab_node(s, n, obj_map);
5810
5811	bitmap_free(obj_map);
5812
5813	return count;
5814}
5815EXPORT_SYMBOL(validate_slab_cache);
5816
5817#ifdef CONFIG_DEBUG_FS
5818/*
5819 * Generate lists of code addresses where slabcache objects are allocated
5820 * and freed.
5821 */
5822
5823struct location {
5824	depot_stack_handle_t handle;
5825	unsigned long count;
5826	unsigned long addr;
5827	unsigned long waste;
5828	long long sum_time;
5829	long min_time;
5830	long max_time;
5831	long min_pid;
5832	long max_pid;
5833	DECLARE_BITMAP(cpus, NR_CPUS);
5834	nodemask_t nodes;
5835};
5836
5837struct loc_track {
5838	unsigned long max;
5839	unsigned long count;
5840	struct location *loc;
5841	loff_t idx;
5842};
5843
5844static struct dentry *slab_debugfs_root;
5845
5846static void free_loc_track(struct loc_track *t)
5847{
5848	if (t->max)
5849		free_pages((unsigned long)t->loc,
5850			get_order(sizeof(struct location) * t->max));
5851}
5852
5853static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
5854{
5855	struct location *l;
5856	int order;
5857
5858	order = get_order(sizeof(struct location) * max);
5859
5860	l = (void *)__get_free_pages(flags, order);
5861	if (!l)
5862		return 0;
5863
5864	if (t->count) {
5865		memcpy(l, t->loc, sizeof(struct location) * t->count);
5866		free_loc_track(t);
5867	}
5868	t->max = max;
5869	t->loc = l;
5870	return 1;
5871}
5872
5873static int add_location(struct loc_track *t, struct kmem_cache *s,
5874				const struct track *track,
5875				unsigned int orig_size)
5876{
5877	long start, end, pos;
5878	struct location *l;
5879	unsigned long caddr, chandle, cwaste;
5880	unsigned long age = jiffies - track->when;
5881	depot_stack_handle_t handle = 0;
5882	unsigned int waste = s->object_size - orig_size;
5883
5884#ifdef CONFIG_STACKDEPOT
5885	handle = READ_ONCE(track->handle);
5886#endif
5887	start = -1;
5888	end = t->count;
5889
5890	for ( ; ; ) {
5891		pos = start + (end - start + 1) / 2;
5892
5893		/*
5894		 * There is nothing at "end". If we end up there
5895		 * we need to add something to before end.
5896		 */
5897		if (pos == end)
5898			break;
5899
5900		l = &t->loc[pos];
5901		caddr = l->addr;
5902		chandle = l->handle;
5903		cwaste = l->waste;
5904		if ((track->addr == caddr) && (handle == chandle) &&
5905			(waste == cwaste)) {
5906
 
5907			l->count++;
5908			if (track->when) {
5909				l->sum_time += age;
5910				if (age < l->min_time)
5911					l->min_time = age;
5912				if (age > l->max_time)
5913					l->max_time = age;
5914
5915				if (track->pid < l->min_pid)
5916					l->min_pid = track->pid;
5917				if (track->pid > l->max_pid)
5918					l->max_pid = track->pid;
5919
5920				cpumask_set_cpu(track->cpu,
5921						to_cpumask(l->cpus));
5922			}
5923			node_set(page_to_nid(virt_to_page(track)), l->nodes);
5924			return 1;
5925		}
5926
5927		if (track->addr < caddr)
5928			end = pos;
5929		else if (track->addr == caddr && handle < chandle)
5930			end = pos;
5931		else if (track->addr == caddr && handle == chandle &&
5932				waste < cwaste)
5933			end = pos;
5934		else
5935			start = pos;
5936	}
5937
5938	/*
5939	 * Not found. Insert new tracking element.
5940	 */
5941	if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
5942		return 0;
5943
5944	l = t->loc + pos;
5945	if (pos < t->count)
5946		memmove(l + 1, l,
5947			(t->count - pos) * sizeof(struct location));
5948	t->count++;
5949	l->count = 1;
5950	l->addr = track->addr;
5951	l->sum_time = age;
5952	l->min_time = age;
5953	l->max_time = age;
5954	l->min_pid = track->pid;
5955	l->max_pid = track->pid;
5956	l->handle = handle;
5957	l->waste = waste;
5958	cpumask_clear(to_cpumask(l->cpus));
5959	cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
5960	nodes_clear(l->nodes);
5961	node_set(page_to_nid(virt_to_page(track)), l->nodes);
5962	return 1;
5963}
5964
5965static void process_slab(struct loc_track *t, struct kmem_cache *s,
5966		struct slab *slab, enum track_item alloc,
5967		unsigned long *obj_map)
5968{
5969	void *addr = slab_address(slab);
5970	bool is_alloc = (alloc == TRACK_ALLOC);
5971	void *p;
 
5972
5973	__fill_map(obj_map, s, slab);
5974
5975	for_each_object(p, s, addr, slab->objects)
5976		if (!test_bit(__obj_to_index(s, addr, p), obj_map))
5977			add_location(t, s, get_track(s, p, alloc),
5978				     is_alloc ? get_orig_size(s, p) :
5979						s->object_size);
5980}
5981#endif  /* CONFIG_DEBUG_FS   */
5982#endif	/* CONFIG_SLUB_DEBUG */
5983
5984#ifdef SLAB_SUPPORTS_SYSFS
5985enum slab_stat_type {
5986	SL_ALL,			/* All slabs */
5987	SL_PARTIAL,		/* Only partially allocated slabs */
5988	SL_CPU,			/* Only slabs used for cpu caches */
5989	SL_OBJECTS,		/* Determine allocated objects not slabs */
5990	SL_TOTAL		/* Determine object capacity not slabs */
5991};
5992
5993#define SO_ALL		(1 << SL_ALL)
5994#define SO_PARTIAL	(1 << SL_PARTIAL)
5995#define SO_CPU		(1 << SL_CPU)
5996#define SO_OBJECTS	(1 << SL_OBJECTS)
5997#define SO_TOTAL	(1 << SL_TOTAL)
5998
5999static ssize_t show_slab_objects(struct kmem_cache *s,
6000				 char *buf, unsigned long flags)
6001{
6002	unsigned long total = 0;
6003	int node;
6004	int x;
6005	unsigned long *nodes;
6006	int len = 0;
6007
6008	nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
6009	if (!nodes)
6010		return -ENOMEM;
6011
6012	if (flags & SO_CPU) {
6013		int cpu;
6014
6015		for_each_possible_cpu(cpu) {
6016			struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
6017							       cpu);
6018			int node;
6019			struct slab *slab;
6020
6021			slab = READ_ONCE(c->slab);
6022			if (!slab)
6023				continue;
6024
6025			node = slab_nid(slab);
6026			if (flags & SO_TOTAL)
6027				x = slab->objects;
6028			else if (flags & SO_OBJECTS)
6029				x = slab->inuse;
6030			else
6031				x = 1;
6032
6033			total += x;
6034			nodes[node] += x;
6035
6036#ifdef CONFIG_SLUB_CPU_PARTIAL
6037			slab = slub_percpu_partial_read_once(c);
6038			if (slab) {
6039				node = slab_nid(slab);
6040				if (flags & SO_TOTAL)
6041					WARN_ON_ONCE(1);
6042				else if (flags & SO_OBJECTS)
6043					WARN_ON_ONCE(1);
6044				else
6045					x = slab->slabs;
6046				total += x;
6047				nodes[node] += x;
6048			}
6049#endif
6050		}
6051	}
6052
6053	/*
6054	 * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
6055	 * already held which will conflict with an existing lock order:
6056	 *
6057	 * mem_hotplug_lock->slab_mutex->kernfs_mutex
6058	 *
6059	 * We don't really need mem_hotplug_lock (to hold off
6060	 * slab_mem_going_offline_callback) here because slab's memory hot
6061	 * unplug code doesn't destroy the kmem_cache->node[] data.
6062	 */
6063
6064#ifdef CONFIG_SLUB_DEBUG
6065	if (flags & SO_ALL) {
6066		struct kmem_cache_node *n;
6067
6068		for_each_kmem_cache_node(s, node, n) {
6069
6070			if (flags & SO_TOTAL)
6071				x = node_nr_objs(n);
6072			else if (flags & SO_OBJECTS)
6073				x = node_nr_objs(n) - count_partial(n, count_free);
 
6074			else
6075				x = node_nr_slabs(n);
6076			total += x;
6077			nodes[node] += x;
6078		}
6079
6080	} else
6081#endif
6082	if (flags & SO_PARTIAL) {
6083		struct kmem_cache_node *n;
6084
6085		for_each_kmem_cache_node(s, node, n) {
6086			if (flags & SO_TOTAL)
6087				x = count_partial(n, count_total);
6088			else if (flags & SO_OBJECTS)
6089				x = count_partial(n, count_inuse);
6090			else
6091				x = n->nr_partial;
6092			total += x;
6093			nodes[node] += x;
6094		}
6095	}
6096
6097	len += sysfs_emit_at(buf, len, "%lu", total);
6098#ifdef CONFIG_NUMA
6099	for (node = 0; node < nr_node_ids; node++) {
6100		if (nodes[node])
6101			len += sysfs_emit_at(buf, len, " N%d=%lu",
6102					     node, nodes[node]);
6103	}
6104#endif
6105	len += sysfs_emit_at(buf, len, "\n");
6106	kfree(nodes);
6107
6108	return len;
6109}
6110
6111#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
6112#define to_slab(n) container_of(n, struct kmem_cache, kobj)
6113
6114struct slab_attribute {
6115	struct attribute attr;
6116	ssize_t (*show)(struct kmem_cache *s, char *buf);
6117	ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
6118};
6119
6120#define SLAB_ATTR_RO(_name) \
6121	static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
 
6122
6123#define SLAB_ATTR(_name) \
6124	static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
 
6125
6126static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
6127{
6128	return sysfs_emit(buf, "%u\n", s->size);
6129}
6130SLAB_ATTR_RO(slab_size);
6131
6132static ssize_t align_show(struct kmem_cache *s, char *buf)
6133{
6134	return sysfs_emit(buf, "%u\n", s->align);
6135}
6136SLAB_ATTR_RO(align);
6137
6138static ssize_t object_size_show(struct kmem_cache *s, char *buf)
6139{
6140	return sysfs_emit(buf, "%u\n", s->object_size);
6141}
6142SLAB_ATTR_RO(object_size);
6143
6144static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
6145{
6146	return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
6147}
6148SLAB_ATTR_RO(objs_per_slab);
6149
6150static ssize_t order_show(struct kmem_cache *s, char *buf)
6151{
6152	return sysfs_emit(buf, "%u\n", oo_order(s->oo));
6153}
6154SLAB_ATTR_RO(order);
6155
6156static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
6157{
6158	return sysfs_emit(buf, "%lu\n", s->min_partial);
6159}
6160
6161static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
6162				 size_t length)
6163{
6164	unsigned long min;
6165	int err;
6166
6167	err = kstrtoul(buf, 10, &min);
6168	if (err)
6169		return err;
6170
6171	s->min_partial = min;
6172	return length;
6173}
6174SLAB_ATTR(min_partial);
6175
6176static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
6177{
6178	unsigned int nr_partial = 0;
6179#ifdef CONFIG_SLUB_CPU_PARTIAL
6180	nr_partial = s->cpu_partial;
6181#endif
6182
6183	return sysfs_emit(buf, "%u\n", nr_partial);
6184}
6185
6186static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
6187				 size_t length)
6188{
6189	unsigned int objects;
6190	int err;
6191
6192	err = kstrtouint(buf, 10, &objects);
6193	if (err)
6194		return err;
6195	if (objects && !kmem_cache_has_cpu_partial(s))
6196		return -EINVAL;
6197
6198	slub_set_cpu_partial(s, objects);
6199	flush_all(s);
6200	return length;
6201}
6202SLAB_ATTR(cpu_partial);
6203
6204static ssize_t ctor_show(struct kmem_cache *s, char *buf)
6205{
6206	if (!s->ctor)
6207		return 0;
6208	return sysfs_emit(buf, "%pS\n", s->ctor);
6209}
6210SLAB_ATTR_RO(ctor);
6211
6212static ssize_t aliases_show(struct kmem_cache *s, char *buf)
6213{
6214	return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
6215}
6216SLAB_ATTR_RO(aliases);
6217
6218static ssize_t partial_show(struct kmem_cache *s, char *buf)
6219{
6220	return show_slab_objects(s, buf, SO_PARTIAL);
6221}
6222SLAB_ATTR_RO(partial);
6223
6224static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
6225{
6226	return show_slab_objects(s, buf, SO_CPU);
6227}
6228SLAB_ATTR_RO(cpu_slabs);
6229
 
 
 
 
 
 
6230static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
6231{
6232	return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
6233}
6234SLAB_ATTR_RO(objects_partial);
6235
6236static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
6237{
6238	int objects = 0;
6239	int slabs = 0;
6240	int cpu __maybe_unused;
6241	int len = 0;
6242
6243#ifdef CONFIG_SLUB_CPU_PARTIAL
6244	for_each_online_cpu(cpu) {
6245		struct slab *slab;
6246
6247		slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
6248
6249		if (slab)
6250			slabs += slab->slabs;
 
 
6251	}
6252#endif
6253
6254	/* Approximate half-full slabs, see slub_set_cpu_partial() */
6255	objects = (slabs * oo_objects(s->oo)) / 2;
6256	len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
6257
6258#ifdef CONFIG_SLUB_CPU_PARTIAL
6259	for_each_online_cpu(cpu) {
6260		struct slab *slab;
6261
6262		slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
6263		if (slab) {
6264			slabs = READ_ONCE(slab->slabs);
6265			objects = (slabs * oo_objects(s->oo)) / 2;
6266			len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
6267					     cpu, objects, slabs);
6268		}
6269	}
6270#endif
6271	len += sysfs_emit_at(buf, len, "\n");
6272
6273	return len;
6274}
6275SLAB_ATTR_RO(slabs_cpu_partial);
6276
6277static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
6278{
6279	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
6280}
6281SLAB_ATTR_RO(reclaim_account);
6282
6283static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
6284{
6285	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
6286}
6287SLAB_ATTR_RO(hwcache_align);
6288
6289#ifdef CONFIG_ZONE_DMA
6290static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
6291{
6292	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
6293}
6294SLAB_ATTR_RO(cache_dma);
6295#endif
6296
6297#ifdef CONFIG_HARDENED_USERCOPY
6298static ssize_t usersize_show(struct kmem_cache *s, char *buf)
6299{
6300	return sysfs_emit(buf, "%u\n", s->usersize);
6301}
6302SLAB_ATTR_RO(usersize);
6303#endif
6304
6305static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
6306{
6307	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
6308}
6309SLAB_ATTR_RO(destroy_by_rcu);
6310
6311#ifdef CONFIG_SLUB_DEBUG
6312static ssize_t slabs_show(struct kmem_cache *s, char *buf)
6313{
6314	return show_slab_objects(s, buf, SO_ALL);
6315}
6316SLAB_ATTR_RO(slabs);
6317
6318static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
6319{
6320	return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
6321}
6322SLAB_ATTR_RO(total_objects);
6323
6324static ssize_t objects_show(struct kmem_cache *s, char *buf)
6325{
6326	return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
6327}
6328SLAB_ATTR_RO(objects);
6329
6330static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
6331{
6332	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
6333}
6334SLAB_ATTR_RO(sanity_checks);
6335
6336static ssize_t trace_show(struct kmem_cache *s, char *buf)
6337{
6338	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
6339}
6340SLAB_ATTR_RO(trace);
6341
6342static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
6343{
6344	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
6345}
6346
6347SLAB_ATTR_RO(red_zone);
6348
6349static ssize_t poison_show(struct kmem_cache *s, char *buf)
6350{
6351	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
6352}
6353
6354SLAB_ATTR_RO(poison);
6355
6356static ssize_t store_user_show(struct kmem_cache *s, char *buf)
6357{
6358	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
6359}
6360
6361SLAB_ATTR_RO(store_user);
6362
6363static ssize_t validate_show(struct kmem_cache *s, char *buf)
6364{
6365	return 0;
6366}
6367
6368static ssize_t validate_store(struct kmem_cache *s,
6369			const char *buf, size_t length)
6370{
6371	int ret = -EINVAL;
6372
6373	if (buf[0] == '1' && kmem_cache_debug(s)) {
6374		ret = validate_slab_cache(s);
6375		if (ret >= 0)
6376			ret = length;
6377	}
6378	return ret;
6379}
6380SLAB_ATTR(validate);
6381
6382#endif /* CONFIG_SLUB_DEBUG */
6383
6384#ifdef CONFIG_FAILSLAB
6385static ssize_t failslab_show(struct kmem_cache *s, char *buf)
6386{
6387	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
6388}
6389
6390static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
6391				size_t length)
6392{
6393	if (s->refcount > 1)
6394		return -EINVAL;
6395
6396	if (buf[0] == '1')
6397		WRITE_ONCE(s->flags, s->flags | SLAB_FAILSLAB);
6398	else
6399		WRITE_ONCE(s->flags, s->flags & ~SLAB_FAILSLAB);
6400
6401	return length;
6402}
6403SLAB_ATTR(failslab);
6404#endif
6405
6406static ssize_t shrink_show(struct kmem_cache *s, char *buf)
6407{
6408	return 0;
6409}
6410
6411static ssize_t shrink_store(struct kmem_cache *s,
6412			const char *buf, size_t length)
6413{
6414	if (buf[0] == '1')
6415		kmem_cache_shrink(s);
6416	else
6417		return -EINVAL;
6418	return length;
6419}
6420SLAB_ATTR(shrink);
6421
6422#ifdef CONFIG_NUMA
6423static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
6424{
6425	return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
6426}
6427
6428static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
6429				const char *buf, size_t length)
6430{
6431	unsigned int ratio;
6432	int err;
6433
6434	err = kstrtouint(buf, 10, &ratio);
6435	if (err)
6436		return err;
6437	if (ratio > 100)
6438		return -ERANGE;
6439
6440	s->remote_node_defrag_ratio = ratio * 10;
6441
6442	return length;
6443}
6444SLAB_ATTR(remote_node_defrag_ratio);
6445#endif
6446
6447#ifdef CONFIG_SLUB_STATS
6448static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
6449{
6450	unsigned long sum  = 0;
6451	int cpu;
6452	int len = 0;
6453	int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
6454
6455	if (!data)
6456		return -ENOMEM;
6457
6458	for_each_online_cpu(cpu) {
6459		unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
6460
6461		data[cpu] = x;
6462		sum += x;
6463	}
6464
6465	len += sysfs_emit_at(buf, len, "%lu", sum);
6466
6467#ifdef CONFIG_SMP
6468	for_each_online_cpu(cpu) {
6469		if (data[cpu])
6470			len += sysfs_emit_at(buf, len, " C%d=%u",
6471					     cpu, data[cpu]);
6472	}
6473#endif
6474	kfree(data);
6475	len += sysfs_emit_at(buf, len, "\n");
6476
6477	return len;
6478}
6479
6480static void clear_stat(struct kmem_cache *s, enum stat_item si)
6481{
6482	int cpu;
6483
6484	for_each_online_cpu(cpu)
6485		per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
6486}
6487
6488#define STAT_ATTR(si, text) 					\
6489static ssize_t text##_show(struct kmem_cache *s, char *buf)	\
6490{								\
6491	return show_stat(s, buf, si);				\
6492}								\
6493static ssize_t text##_store(struct kmem_cache *s,		\
6494				const char *buf, size_t length)	\
6495{								\
6496	if (buf[0] != '0')					\
6497		return -EINVAL;					\
6498	clear_stat(s, si);					\
6499	return length;						\
6500}								\
6501SLAB_ATTR(text);						\
6502
6503STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
6504STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
6505STAT_ATTR(FREE_FASTPATH, free_fastpath);
6506STAT_ATTR(FREE_SLOWPATH, free_slowpath);
6507STAT_ATTR(FREE_FROZEN, free_frozen);
6508STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
6509STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
6510STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
6511STAT_ATTR(ALLOC_SLAB, alloc_slab);
6512STAT_ATTR(ALLOC_REFILL, alloc_refill);
6513STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
6514STAT_ATTR(FREE_SLAB, free_slab);
6515STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
6516STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
6517STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
6518STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
6519STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
6520STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
6521STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
6522STAT_ATTR(ORDER_FALLBACK, order_fallback);
6523STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
6524STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
6525STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
6526STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
6527STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
6528STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
6529#endif	/* CONFIG_SLUB_STATS */
6530
6531#ifdef CONFIG_KFENCE
6532static ssize_t skip_kfence_show(struct kmem_cache *s, char *buf)
6533{
6534	return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_SKIP_KFENCE));
6535}
6536
6537static ssize_t skip_kfence_store(struct kmem_cache *s,
6538			const char *buf, size_t length)
6539{
6540	int ret = length;
6541
6542	if (buf[0] == '0')
6543		s->flags &= ~SLAB_SKIP_KFENCE;
6544	else if (buf[0] == '1')
6545		s->flags |= SLAB_SKIP_KFENCE;
6546	else
6547		ret = -EINVAL;
6548
6549	return ret;
6550}
6551SLAB_ATTR(skip_kfence);
6552#endif
6553
6554static struct attribute *slab_attrs[] = {
6555	&slab_size_attr.attr,
6556	&object_size_attr.attr,
6557	&objs_per_slab_attr.attr,
6558	&order_attr.attr,
6559	&min_partial_attr.attr,
6560	&cpu_partial_attr.attr,
 
6561	&objects_partial_attr.attr,
6562	&partial_attr.attr,
6563	&cpu_slabs_attr.attr,
6564	&ctor_attr.attr,
6565	&aliases_attr.attr,
6566	&align_attr.attr,
6567	&hwcache_align_attr.attr,
6568	&reclaim_account_attr.attr,
6569	&destroy_by_rcu_attr.attr,
6570	&shrink_attr.attr,
6571	&slabs_cpu_partial_attr.attr,
6572#ifdef CONFIG_SLUB_DEBUG
6573	&total_objects_attr.attr,
6574	&objects_attr.attr,
6575	&slabs_attr.attr,
6576	&sanity_checks_attr.attr,
6577	&trace_attr.attr,
6578	&red_zone_attr.attr,
6579	&poison_attr.attr,
6580	&store_user_attr.attr,
6581	&validate_attr.attr,
6582#endif
6583#ifdef CONFIG_ZONE_DMA
6584	&cache_dma_attr.attr,
6585#endif
6586#ifdef CONFIG_NUMA
6587	&remote_node_defrag_ratio_attr.attr,
6588#endif
6589#ifdef CONFIG_SLUB_STATS
6590	&alloc_fastpath_attr.attr,
6591	&alloc_slowpath_attr.attr,
6592	&free_fastpath_attr.attr,
6593	&free_slowpath_attr.attr,
6594	&free_frozen_attr.attr,
6595	&free_add_partial_attr.attr,
6596	&free_remove_partial_attr.attr,
6597	&alloc_from_partial_attr.attr,
6598	&alloc_slab_attr.attr,
6599	&alloc_refill_attr.attr,
6600	&alloc_node_mismatch_attr.attr,
6601	&free_slab_attr.attr,
6602	&cpuslab_flush_attr.attr,
6603	&deactivate_full_attr.attr,
6604	&deactivate_empty_attr.attr,
6605	&deactivate_to_head_attr.attr,
6606	&deactivate_to_tail_attr.attr,
6607	&deactivate_remote_frees_attr.attr,
6608	&deactivate_bypass_attr.attr,
6609	&order_fallback_attr.attr,
6610	&cmpxchg_double_fail_attr.attr,
6611	&cmpxchg_double_cpu_fail_attr.attr,
6612	&cpu_partial_alloc_attr.attr,
6613	&cpu_partial_free_attr.attr,
6614	&cpu_partial_node_attr.attr,
6615	&cpu_partial_drain_attr.attr,
6616#endif
6617#ifdef CONFIG_FAILSLAB
6618	&failslab_attr.attr,
6619#endif
6620#ifdef CONFIG_HARDENED_USERCOPY
6621	&usersize_attr.attr,
6622#endif
6623#ifdef CONFIG_KFENCE
6624	&skip_kfence_attr.attr,
6625#endif
6626
6627	NULL
6628};
6629
6630static const struct attribute_group slab_attr_group = {
6631	.attrs = slab_attrs,
6632};
6633
6634static ssize_t slab_attr_show(struct kobject *kobj,
6635				struct attribute *attr,
6636				char *buf)
6637{
6638	struct slab_attribute *attribute;
6639	struct kmem_cache *s;
 
6640
6641	attribute = to_slab_attr(attr);
6642	s = to_slab(kobj);
6643
6644	if (!attribute->show)
6645		return -EIO;
6646
6647	return attribute->show(s, buf);
 
 
6648}
6649
6650static ssize_t slab_attr_store(struct kobject *kobj,
6651				struct attribute *attr,
6652				const char *buf, size_t len)
6653{
6654	struct slab_attribute *attribute;
6655	struct kmem_cache *s;
 
6656
6657	attribute = to_slab_attr(attr);
6658	s = to_slab(kobj);
6659
6660	if (!attribute->store)
6661		return -EIO;
6662
6663	return attribute->store(s, buf, len);
 
6664}
6665
6666static void kmem_cache_release(struct kobject *k)
6667{
6668	slab_kmem_cache_release(to_slab(k));
6669}
6670
6671static const struct sysfs_ops slab_sysfs_ops = {
6672	.show = slab_attr_show,
6673	.store = slab_attr_store,
6674};
6675
6676static const struct kobj_type slab_ktype = {
6677	.sysfs_ops = &slab_sysfs_ops,
6678	.release = kmem_cache_release,
6679};
6680
6681static struct kset *slab_kset;
6682
6683static inline struct kset *cache_kset(struct kmem_cache *s)
6684{
6685	return slab_kset;
6686}
6687
6688#define ID_STR_LENGTH 32
6689
6690/* Create a unique string id for a slab cache:
6691 *
6692 * Format	:[flags-]size
6693 */
6694static char *create_unique_id(struct kmem_cache *s)
6695{
6696	char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
6697	char *p = name;
6698
6699	if (!name)
6700		return ERR_PTR(-ENOMEM);
6701
6702	*p++ = ':';
6703	/*
6704	 * First flags affecting slabcache operations. We will only
6705	 * get here for aliasable slabs so we do not need to support
6706	 * too many flags. The flags here must cover all flags that
6707	 * are matched during merging to guarantee that the id is
6708	 * unique.
6709	 */
6710	if (s->flags & SLAB_CACHE_DMA)
6711		*p++ = 'd';
6712	if (s->flags & SLAB_CACHE_DMA32)
6713		*p++ = 'D';
6714	if (s->flags & SLAB_RECLAIM_ACCOUNT)
6715		*p++ = 'a';
6716	if (s->flags & SLAB_CONSISTENCY_CHECKS)
6717		*p++ = 'F';
6718	if (s->flags & SLAB_ACCOUNT)
6719		*p++ = 'A';
6720	if (p != name + 1)
6721		*p++ = '-';
6722	p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size);
6723
6724	if (WARN_ON(p > name + ID_STR_LENGTH - 1)) {
6725		kfree(name);
6726		return ERR_PTR(-EINVAL);
6727	}
6728	kmsan_unpoison_memory(name, p - name);
6729	return name;
6730}
6731
6732static int sysfs_slab_add(struct kmem_cache *s)
6733{
6734	int err;
6735	const char *name;
6736	struct kset *kset = cache_kset(s);
6737	int unmergeable = slab_unmergeable(s);
6738
 
 
 
 
 
6739	if (!unmergeable && disable_higher_order_debug &&
6740			(slub_debug & DEBUG_METADATA_FLAGS))
6741		unmergeable = 1;
6742
6743	if (unmergeable) {
6744		/*
6745		 * Slabcache can never be merged so we can use the name proper.
6746		 * This is typically the case for debug situations. In that
6747		 * case we can catch duplicate names easily.
6748		 */
6749		sysfs_remove_link(&slab_kset->kobj, s->name);
6750		name = s->name;
6751	} else {
6752		/*
6753		 * Create a unique name for the slab as a target
6754		 * for the symlinks.
6755		 */
6756		name = create_unique_id(s);
6757		if (IS_ERR(name))
6758			return PTR_ERR(name);
6759	}
6760
6761	s->kobj.kset = kset;
6762	err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
6763	if (err)
6764		goto out;
6765
6766	err = sysfs_create_group(&s->kobj, &slab_attr_group);
6767	if (err)
6768		goto out_del_kobj;
6769
6770	if (!unmergeable) {
6771		/* Setup first alias */
6772		sysfs_slab_alias(s, s->name);
6773	}
6774out:
6775	if (!unmergeable)
6776		kfree(name);
6777	return err;
6778out_del_kobj:
6779	kobject_del(&s->kobj);
6780	goto out;
6781}
6782
6783void sysfs_slab_unlink(struct kmem_cache *s)
6784{
6785	kobject_del(&s->kobj);
 
6786}
6787
6788void sysfs_slab_release(struct kmem_cache *s)
6789{
6790	kobject_put(&s->kobj);
 
6791}
6792
6793/*
6794 * Need to buffer aliases during bootup until sysfs becomes
6795 * available lest we lose that information.
6796 */
6797struct saved_alias {
6798	struct kmem_cache *s;
6799	const char *name;
6800	struct saved_alias *next;
6801};
6802
6803static struct saved_alias *alias_list;
6804
6805static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
6806{
6807	struct saved_alias *al;
6808
6809	if (slab_state == FULL) {
6810		/*
6811		 * If we have a leftover link then remove it.
6812		 */
6813		sysfs_remove_link(&slab_kset->kobj, name);
6814		return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
6815	}
6816
6817	al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
6818	if (!al)
6819		return -ENOMEM;
6820
6821	al->s = s;
6822	al->name = name;
6823	al->next = alias_list;
6824	alias_list = al;
6825	kmsan_unpoison_memory(al, sizeof(*al));
6826	return 0;
6827}
6828
6829static int __init slab_sysfs_init(void)
6830{
6831	struct kmem_cache *s;
6832	int err;
6833
6834	mutex_lock(&slab_mutex);
6835
6836	slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
6837	if (!slab_kset) {
6838		mutex_unlock(&slab_mutex);
6839		pr_err("Cannot register slab subsystem.\n");
6840		return -ENOMEM;
6841	}
6842
6843	slab_state = FULL;
6844
6845	list_for_each_entry(s, &slab_caches, list) {
6846		err = sysfs_slab_add(s);
6847		if (err)
6848			pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
6849			       s->name);
6850	}
6851
6852	while (alias_list) {
6853		struct saved_alias *al = alias_list;
6854
6855		alias_list = alias_list->next;
6856		err = sysfs_slab_alias(al->s, al->name);
6857		if (err)
6858			pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
6859			       al->name);
6860		kfree(al);
6861	}
6862
6863	mutex_unlock(&slab_mutex);
6864	return 0;
6865}
6866late_initcall(slab_sysfs_init);
6867#endif /* SLAB_SUPPORTS_SYSFS */
 
6868
6869#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
6870static int slab_debugfs_show(struct seq_file *seq, void *v)
6871{
6872	struct loc_track *t = seq->private;
6873	struct location *l;
6874	unsigned long idx;
 
6875
6876	idx = (unsigned long) t->idx;
6877	if (idx < t->count) {
6878		l = &t->loc[idx];
6879
6880		seq_printf(seq, "%7ld ", l->count);
6881
6882		if (l->addr)
6883			seq_printf(seq, "%pS", (void *)l->addr);
6884		else
6885			seq_puts(seq, "<not-available>");
6886
6887		if (l->waste)
6888			seq_printf(seq, " waste=%lu/%lu",
6889				l->count * l->waste, l->waste);
6890
6891		if (l->sum_time != l->min_time) {
6892			seq_printf(seq, " age=%ld/%llu/%ld",
6893				l->min_time, div_u64(l->sum_time, l->count),
6894				l->max_time);
6895		} else
6896			seq_printf(seq, " age=%ld", l->min_time);
6897
6898		if (l->min_pid != l->max_pid)
6899			seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid);
6900		else
6901			seq_printf(seq, " pid=%ld",
6902				l->min_pid);
6903
6904		if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)))
6905			seq_printf(seq, " cpus=%*pbl",
6906				 cpumask_pr_args(to_cpumask(l->cpus)));
6907
6908		if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
6909			seq_printf(seq, " nodes=%*pbl",
6910				 nodemask_pr_args(&l->nodes));
6911
6912#ifdef CONFIG_STACKDEPOT
6913		{
6914			depot_stack_handle_t handle;
6915			unsigned long *entries;
6916			unsigned int nr_entries, j;
6917
6918			handle = READ_ONCE(l->handle);
6919			if (handle) {
6920				nr_entries = stack_depot_fetch(handle, &entries);
6921				seq_puts(seq, "\n");
6922				for (j = 0; j < nr_entries; j++)
6923					seq_printf(seq, "        %pS\n", (void *)entries[j]);
6924			}
6925		}
6926#endif
6927		seq_puts(seq, "\n");
6928	}
6929
6930	if (!idx && !t->count)
6931		seq_puts(seq, "No data\n");
6932
6933	return 0;
6934}
6935
6936static void slab_debugfs_stop(struct seq_file *seq, void *v)
6937{
6938}
6939
6940static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
6941{
6942	struct loc_track *t = seq->private;
6943
6944	t->idx = ++(*ppos);
 
6945	if (*ppos <= t->count)
6946		return ppos;
6947
6948	return NULL;
6949}
6950
6951static int cmp_loc_by_count(const void *a, const void *b, const void *data)
6952{
6953	struct location *loc1 = (struct location *)a;
6954	struct location *loc2 = (struct location *)b;
6955
6956	if (loc1->count > loc2->count)
6957		return -1;
6958	else
6959		return 1;
6960}
6961
6962static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
6963{
6964	struct loc_track *t = seq->private;
6965
6966	t->idx = *ppos;
6967	return ppos;
6968}
6969
6970static const struct seq_operations slab_debugfs_sops = {
6971	.start  = slab_debugfs_start,
6972	.next   = slab_debugfs_next,
6973	.stop   = slab_debugfs_stop,
6974	.show   = slab_debugfs_show,
6975};
6976
6977static int slab_debug_trace_open(struct inode *inode, struct file *filep)
6978{
6979
6980	struct kmem_cache_node *n;
6981	enum track_item alloc;
6982	int node;
6983	struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
6984						sizeof(struct loc_track));
6985	struct kmem_cache *s = file_inode(filep)->i_private;
6986	unsigned long *obj_map;
6987
6988	if (!t)
6989		return -ENOMEM;
6990
6991	obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
6992	if (!obj_map) {
6993		seq_release_private(inode, filep);
6994		return -ENOMEM;
6995	}
6996
6997	if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
6998		alloc = TRACK_ALLOC;
6999	else
7000		alloc = TRACK_FREE;
7001
7002	if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
7003		bitmap_free(obj_map);
7004		seq_release_private(inode, filep);
7005		return -ENOMEM;
7006	}
 
 
7007
7008	for_each_kmem_cache_node(s, node, n) {
7009		unsigned long flags;
7010		struct slab *slab;
7011
7012		if (!node_nr_slabs(n))
7013			continue;
7014
7015		spin_lock_irqsave(&n->list_lock, flags);
7016		list_for_each_entry(slab, &n->partial, slab_list)
7017			process_slab(t, s, slab, alloc, obj_map);
7018		list_for_each_entry(slab, &n->full, slab_list)
7019			process_slab(t, s, slab, alloc, obj_map);
7020		spin_unlock_irqrestore(&n->list_lock, flags);
7021	}
7022
7023	/* Sort locations by count */
7024	sort_r(t->loc, t->count, sizeof(struct location),
7025		cmp_loc_by_count, NULL, NULL);
7026
7027	bitmap_free(obj_map);
7028	return 0;
7029}
7030
7031static int slab_debug_trace_release(struct inode *inode, struct file *file)
7032{
7033	struct seq_file *seq = file->private_data;
7034	struct loc_track *t = seq->private;
7035
7036	free_loc_track(t);
7037	return seq_release_private(inode, file);
7038}
7039
7040static const struct file_operations slab_debugfs_fops = {
7041	.open    = slab_debug_trace_open,
7042	.read    = seq_read,
7043	.llseek  = seq_lseek,
7044	.release = slab_debug_trace_release,
7045};
7046
7047static void debugfs_slab_add(struct kmem_cache *s)
7048{
7049	struct dentry *slab_cache_dir;
7050
7051	if (unlikely(!slab_debugfs_root))
7052		return;
7053
7054	slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
7055
7056	debugfs_create_file("alloc_traces", 0400,
7057		slab_cache_dir, s, &slab_debugfs_fops);
7058
7059	debugfs_create_file("free_traces", 0400,
7060		slab_cache_dir, s, &slab_debugfs_fops);
7061}
7062
7063void debugfs_slab_release(struct kmem_cache *s)
7064{
7065	debugfs_lookup_and_remove(s->name, slab_debugfs_root);
7066}
7067
7068static int __init slab_debugfs_init(void)
7069{
7070	struct kmem_cache *s;
7071
7072	slab_debugfs_root = debugfs_create_dir("slab", NULL);
7073
7074	list_for_each_entry(s, &slab_caches, list)
7075		if (s->flags & SLAB_STORE_USER)
7076			debugfs_slab_add(s);
7077
7078	return 0;
7079
7080}
7081__initcall(slab_debugfs_init);
7082#endif
7083/*
7084 * The /proc/slabinfo ABI
7085 */
7086#ifdef CONFIG_SLUB_DEBUG
7087void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
7088{
7089	unsigned long nr_slabs = 0;
7090	unsigned long nr_objs = 0;
7091	unsigned long nr_free = 0;
7092	int node;
7093	struct kmem_cache_node *n;
7094
7095	for_each_kmem_cache_node(s, node, n) {
7096		nr_slabs += node_nr_slabs(n);
7097		nr_objs += node_nr_objs(n);
7098		nr_free += count_partial(n, count_free);
7099	}
7100
7101	sinfo->active_objs = nr_objs - nr_free;
7102	sinfo->num_objs = nr_objs;
7103	sinfo->active_slabs = nr_slabs;
7104	sinfo->num_slabs = nr_slabs;
7105	sinfo->objects_per_slab = oo_objects(s->oo);
7106	sinfo->cache_order = oo_order(s->oo);
7107}
7108
7109void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
7110{
7111}
7112
7113ssize_t slabinfo_write(struct file *file, const char __user *buffer,
7114		       size_t count, loff_t *ppos)
7115{
7116	return -EIO;
7117}
7118#endif /* CONFIG_SLUB_DEBUG */