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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Slab allocator functions that are independent of the allocator strategy
4 *
5 * (C) 2012 Christoph Lameter <cl@linux.com>
6 */
7#include <linux/slab.h>
8
9#include <linux/mm.h>
10#include <linux/poison.h>
11#include <linux/interrupt.h>
12#include <linux/memory.h>
13#include <linux/cache.h>
14#include <linux/compiler.h>
15#include <linux/module.h>
16#include <linux/cpu.h>
17#include <linux/uaccess.h>
18#include <linux/seq_file.h>
19#include <linux/proc_fs.h>
20#include <linux/debugfs.h>
21#include <asm/cacheflush.h>
22#include <asm/tlbflush.h>
23#include <asm/page.h>
24#include <linux/memcontrol.h>
25
26#define CREATE_TRACE_POINTS
27#include <trace/events/kmem.h>
28
29#include "internal.h"
30
31#include "slab.h"
32
33enum slab_state slab_state;
34LIST_HEAD(slab_caches);
35DEFINE_MUTEX(slab_mutex);
36struct kmem_cache *kmem_cache;
37
38#ifdef CONFIG_HARDENED_USERCOPY
39bool usercopy_fallback __ro_after_init =
40 IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK);
41module_param(usercopy_fallback, bool, 0400);
42MODULE_PARM_DESC(usercopy_fallback,
43 "WARN instead of reject usercopy whitelist violations");
44#endif
45
46static LIST_HEAD(slab_caches_to_rcu_destroy);
47static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
48static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
49 slab_caches_to_rcu_destroy_workfn);
50
51/*
52 * Set of flags that will prevent slab merging
53 */
54#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
55 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
56 SLAB_FAILSLAB | SLAB_KASAN)
57
58#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
59 SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
60
61/*
62 * Merge control. If this is set then no merging of slab caches will occur.
63 */
64static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
65
66static int __init setup_slab_nomerge(char *str)
67{
68 slab_nomerge = true;
69 return 1;
70}
71
72#ifdef CONFIG_SLUB
73__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
74#endif
75
76__setup("slab_nomerge", setup_slab_nomerge);
77
78/*
79 * Determine the size of a slab object
80 */
81unsigned int kmem_cache_size(struct kmem_cache *s)
82{
83 return s->object_size;
84}
85EXPORT_SYMBOL(kmem_cache_size);
86
87#ifdef CONFIG_DEBUG_VM
88static int kmem_cache_sanity_check(const char *name, unsigned int size)
89{
90 if (!name || in_interrupt() || size < sizeof(void *) ||
91 size > KMALLOC_MAX_SIZE) {
92 pr_err("kmem_cache_create(%s) integrity check failed\n", name);
93 return -EINVAL;
94 }
95
96 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
97 return 0;
98}
99#else
100static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
101{
102 return 0;
103}
104#endif
105
106void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
107{
108 size_t i;
109
110 for (i = 0; i < nr; i++) {
111 if (s)
112 kmem_cache_free(s, p[i]);
113 else
114 kfree(p[i]);
115 }
116}
117
118int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
119 void **p)
120{
121 size_t i;
122
123 for (i = 0; i < nr; i++) {
124 void *x = p[i] = kmem_cache_alloc(s, flags);
125 if (!x) {
126 __kmem_cache_free_bulk(s, i, p);
127 return 0;
128 }
129 }
130 return i;
131}
132
133/*
134 * Figure out what the alignment of the objects will be given a set of
135 * flags, a user specified alignment and the size of the objects.
136 */
137static unsigned int calculate_alignment(slab_flags_t flags,
138 unsigned int align, unsigned int size)
139{
140 /*
141 * If the user wants hardware cache aligned objects then follow that
142 * suggestion if the object is sufficiently large.
143 *
144 * The hardware cache alignment cannot override the specified
145 * alignment though. If that is greater then use it.
146 */
147 if (flags & SLAB_HWCACHE_ALIGN) {
148 unsigned int ralign;
149
150 ralign = cache_line_size();
151 while (size <= ralign / 2)
152 ralign /= 2;
153 align = max(align, ralign);
154 }
155
156 if (align < ARCH_SLAB_MINALIGN)
157 align = ARCH_SLAB_MINALIGN;
158
159 return ALIGN(align, sizeof(void *));
160}
161
162/*
163 * Find a mergeable slab cache
164 */
165int slab_unmergeable(struct kmem_cache *s)
166{
167 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
168 return 1;
169
170 if (s->ctor)
171 return 1;
172
173 if (s->usersize)
174 return 1;
175
176 /*
177 * We may have set a slab to be unmergeable during bootstrap.
178 */
179 if (s->refcount < 0)
180 return 1;
181
182 return 0;
183}
184
185struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
186 slab_flags_t flags, const char *name, void (*ctor)(void *))
187{
188 struct kmem_cache *s;
189
190 if (slab_nomerge)
191 return NULL;
192
193 if (ctor)
194 return NULL;
195
196 size = ALIGN(size, sizeof(void *));
197 align = calculate_alignment(flags, align, size);
198 size = ALIGN(size, align);
199 flags = kmem_cache_flags(size, flags, name, NULL);
200
201 if (flags & SLAB_NEVER_MERGE)
202 return NULL;
203
204 list_for_each_entry_reverse(s, &slab_caches, list) {
205 if (slab_unmergeable(s))
206 continue;
207
208 if (size > s->size)
209 continue;
210
211 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
212 continue;
213 /*
214 * Check if alignment is compatible.
215 * Courtesy of Adrian Drzewiecki
216 */
217 if ((s->size & ~(align - 1)) != s->size)
218 continue;
219
220 if (s->size - size >= sizeof(void *))
221 continue;
222
223 if (IS_ENABLED(CONFIG_SLAB) && align &&
224 (align > s->align || s->align % align))
225 continue;
226
227 return s;
228 }
229 return NULL;
230}
231
232static struct kmem_cache *create_cache(const char *name,
233 unsigned int object_size, unsigned int align,
234 slab_flags_t flags, unsigned int useroffset,
235 unsigned int usersize, void (*ctor)(void *),
236 struct kmem_cache *root_cache)
237{
238 struct kmem_cache *s;
239 int err;
240
241 if (WARN_ON(useroffset + usersize > object_size))
242 useroffset = usersize = 0;
243
244 err = -ENOMEM;
245 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
246 if (!s)
247 goto out;
248
249 s->name = name;
250 s->size = s->object_size = object_size;
251 s->align = align;
252 s->ctor = ctor;
253 s->useroffset = useroffset;
254 s->usersize = usersize;
255
256 err = __kmem_cache_create(s, flags);
257 if (err)
258 goto out_free_cache;
259
260 s->refcount = 1;
261 list_add(&s->list, &slab_caches);
262out:
263 if (err)
264 return ERR_PTR(err);
265 return s;
266
267out_free_cache:
268 kmem_cache_free(kmem_cache, s);
269 goto out;
270}
271
272/**
273 * kmem_cache_create_usercopy - Create a cache with a region suitable
274 * for copying to userspace
275 * @name: A string which is used in /proc/slabinfo to identify this cache.
276 * @size: The size of objects to be created in this cache.
277 * @align: The required alignment for the objects.
278 * @flags: SLAB flags
279 * @useroffset: Usercopy region offset
280 * @usersize: Usercopy region size
281 * @ctor: A constructor for the objects.
282 *
283 * Cannot be called within a interrupt, but can be interrupted.
284 * The @ctor is run when new pages are allocated by the cache.
285 *
286 * The flags are
287 *
288 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
289 * to catch references to uninitialised memory.
290 *
291 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
292 * for buffer overruns.
293 *
294 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
295 * cacheline. This can be beneficial if you're counting cycles as closely
296 * as davem.
297 *
298 * Return: a pointer to the cache on success, NULL on failure.
299 */
300struct kmem_cache *
301kmem_cache_create_usercopy(const char *name,
302 unsigned int size, unsigned int align,
303 slab_flags_t flags,
304 unsigned int useroffset, unsigned int usersize,
305 void (*ctor)(void *))
306{
307 struct kmem_cache *s = NULL;
308 const char *cache_name;
309 int err;
310
311 get_online_cpus();
312 get_online_mems();
313
314 mutex_lock(&slab_mutex);
315
316 err = kmem_cache_sanity_check(name, size);
317 if (err) {
318 goto out_unlock;
319 }
320
321 /* Refuse requests with allocator specific flags */
322 if (flags & ~SLAB_FLAGS_PERMITTED) {
323 err = -EINVAL;
324 goto out_unlock;
325 }
326
327 /*
328 * Some allocators will constraint the set of valid flags to a subset
329 * of all flags. We expect them to define CACHE_CREATE_MASK in this
330 * case, and we'll just provide them with a sanitized version of the
331 * passed flags.
332 */
333 flags &= CACHE_CREATE_MASK;
334
335 /* Fail closed on bad usersize of useroffset values. */
336 if (WARN_ON(!usersize && useroffset) ||
337 WARN_ON(size < usersize || size - usersize < useroffset))
338 usersize = useroffset = 0;
339
340 if (!usersize)
341 s = __kmem_cache_alias(name, size, align, flags, ctor);
342 if (s)
343 goto out_unlock;
344
345 cache_name = kstrdup_const(name, GFP_KERNEL);
346 if (!cache_name) {
347 err = -ENOMEM;
348 goto out_unlock;
349 }
350
351 s = create_cache(cache_name, size,
352 calculate_alignment(flags, align, size),
353 flags, useroffset, usersize, ctor, NULL);
354 if (IS_ERR(s)) {
355 err = PTR_ERR(s);
356 kfree_const(cache_name);
357 }
358
359out_unlock:
360 mutex_unlock(&slab_mutex);
361
362 put_online_mems();
363 put_online_cpus();
364
365 if (err) {
366 if (flags & SLAB_PANIC)
367 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
368 name, err);
369 else {
370 pr_warn("kmem_cache_create(%s) failed with error %d\n",
371 name, err);
372 dump_stack();
373 }
374 return NULL;
375 }
376 return s;
377}
378EXPORT_SYMBOL(kmem_cache_create_usercopy);
379
380/**
381 * kmem_cache_create - Create a cache.
382 * @name: A string which is used in /proc/slabinfo to identify this cache.
383 * @size: The size of objects to be created in this cache.
384 * @align: The required alignment for the objects.
385 * @flags: SLAB flags
386 * @ctor: A constructor for the objects.
387 *
388 * Cannot be called within a interrupt, but can be interrupted.
389 * The @ctor is run when new pages are allocated by the cache.
390 *
391 * The flags are
392 *
393 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
394 * to catch references to uninitialised memory.
395 *
396 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
397 * for buffer overruns.
398 *
399 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
400 * cacheline. This can be beneficial if you're counting cycles as closely
401 * as davem.
402 *
403 * Return: a pointer to the cache on success, NULL on failure.
404 */
405struct kmem_cache *
406kmem_cache_create(const char *name, unsigned int size, unsigned int align,
407 slab_flags_t flags, void (*ctor)(void *))
408{
409 return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
410 ctor);
411}
412EXPORT_SYMBOL(kmem_cache_create);
413
414static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
415{
416 LIST_HEAD(to_destroy);
417 struct kmem_cache *s, *s2;
418
419 /*
420 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
421 * @slab_caches_to_rcu_destroy list. The slab pages are freed
422 * through RCU and the associated kmem_cache are dereferenced
423 * while freeing the pages, so the kmem_caches should be freed only
424 * after the pending RCU operations are finished. As rcu_barrier()
425 * is a pretty slow operation, we batch all pending destructions
426 * asynchronously.
427 */
428 mutex_lock(&slab_mutex);
429 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
430 mutex_unlock(&slab_mutex);
431
432 if (list_empty(&to_destroy))
433 return;
434
435 rcu_barrier();
436
437 list_for_each_entry_safe(s, s2, &to_destroy, list) {
438#ifdef SLAB_SUPPORTS_SYSFS
439 sysfs_slab_release(s);
440#else
441 slab_kmem_cache_release(s);
442#endif
443 }
444}
445
446static int shutdown_cache(struct kmem_cache *s)
447{
448 /* free asan quarantined objects */
449 kasan_cache_shutdown(s);
450
451 if (__kmem_cache_shutdown(s) != 0)
452 return -EBUSY;
453
454 list_del(&s->list);
455
456 if (s->flags & SLAB_TYPESAFE_BY_RCU) {
457#ifdef SLAB_SUPPORTS_SYSFS
458 sysfs_slab_unlink(s);
459#endif
460 list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
461 schedule_work(&slab_caches_to_rcu_destroy_work);
462 } else {
463#ifdef SLAB_SUPPORTS_SYSFS
464 sysfs_slab_unlink(s);
465 sysfs_slab_release(s);
466#else
467 slab_kmem_cache_release(s);
468#endif
469 }
470
471 return 0;
472}
473
474void slab_kmem_cache_release(struct kmem_cache *s)
475{
476 __kmem_cache_release(s);
477 kfree_const(s->name);
478 kmem_cache_free(kmem_cache, s);
479}
480
481void kmem_cache_destroy(struct kmem_cache *s)
482{
483 int err;
484
485 if (unlikely(!s))
486 return;
487
488 get_online_cpus();
489 get_online_mems();
490
491 mutex_lock(&slab_mutex);
492
493 s->refcount--;
494 if (s->refcount)
495 goto out_unlock;
496
497 err = shutdown_cache(s);
498 if (err) {
499 pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
500 s->name);
501 dump_stack();
502 }
503out_unlock:
504 mutex_unlock(&slab_mutex);
505
506 put_online_mems();
507 put_online_cpus();
508}
509EXPORT_SYMBOL(kmem_cache_destroy);
510
511/**
512 * kmem_cache_shrink - Shrink a cache.
513 * @cachep: The cache to shrink.
514 *
515 * Releases as many slabs as possible for a cache.
516 * To help debugging, a zero exit status indicates all slabs were released.
517 *
518 * Return: %0 if all slabs were released, non-zero otherwise
519 */
520int kmem_cache_shrink(struct kmem_cache *cachep)
521{
522 int ret;
523
524 get_online_cpus();
525 get_online_mems();
526 kasan_cache_shrink(cachep);
527 ret = __kmem_cache_shrink(cachep);
528 put_online_mems();
529 put_online_cpus();
530 return ret;
531}
532EXPORT_SYMBOL(kmem_cache_shrink);
533
534bool slab_is_available(void)
535{
536 return slab_state >= UP;
537}
538
539#ifndef CONFIG_SLOB
540/* Create a cache during boot when no slab services are available yet */
541void __init create_boot_cache(struct kmem_cache *s, const char *name,
542 unsigned int size, slab_flags_t flags,
543 unsigned int useroffset, unsigned int usersize)
544{
545 int err;
546 unsigned int align = ARCH_KMALLOC_MINALIGN;
547
548 s->name = name;
549 s->size = s->object_size = size;
550
551 /*
552 * For power of two sizes, guarantee natural alignment for kmalloc
553 * caches, regardless of SL*B debugging options.
554 */
555 if (is_power_of_2(size))
556 align = max(align, size);
557 s->align = calculate_alignment(flags, align, size);
558
559 s->useroffset = useroffset;
560 s->usersize = usersize;
561
562 err = __kmem_cache_create(s, flags);
563
564 if (err)
565 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
566 name, size, err);
567
568 s->refcount = -1; /* Exempt from merging for now */
569}
570
571struct kmem_cache *__init create_kmalloc_cache(const char *name,
572 unsigned int size, slab_flags_t flags,
573 unsigned int useroffset, unsigned int usersize)
574{
575 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
576
577 if (!s)
578 panic("Out of memory when creating slab %s\n", name);
579
580 create_boot_cache(s, name, size, flags, useroffset, usersize);
581 list_add(&s->list, &slab_caches);
582 s->refcount = 1;
583 return s;
584}
585
586struct kmem_cache *
587kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
588{ /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
589EXPORT_SYMBOL(kmalloc_caches);
590
591/*
592 * Conversion table for small slabs sizes / 8 to the index in the
593 * kmalloc array. This is necessary for slabs < 192 since we have non power
594 * of two cache sizes there. The size of larger slabs can be determined using
595 * fls.
596 */
597static u8 size_index[24] __ro_after_init = {
598 3, /* 8 */
599 4, /* 16 */
600 5, /* 24 */
601 5, /* 32 */
602 6, /* 40 */
603 6, /* 48 */
604 6, /* 56 */
605 6, /* 64 */
606 1, /* 72 */
607 1, /* 80 */
608 1, /* 88 */
609 1, /* 96 */
610 7, /* 104 */
611 7, /* 112 */
612 7, /* 120 */
613 7, /* 128 */
614 2, /* 136 */
615 2, /* 144 */
616 2, /* 152 */
617 2, /* 160 */
618 2, /* 168 */
619 2, /* 176 */
620 2, /* 184 */
621 2 /* 192 */
622};
623
624static inline unsigned int size_index_elem(unsigned int bytes)
625{
626 return (bytes - 1) / 8;
627}
628
629/*
630 * Find the kmem_cache structure that serves a given size of
631 * allocation
632 */
633struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
634{
635 unsigned int index;
636
637 if (size <= 192) {
638 if (!size)
639 return ZERO_SIZE_PTR;
640
641 index = size_index[size_index_elem(size)];
642 } else {
643 if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
644 return NULL;
645 index = fls(size - 1);
646 }
647
648 return kmalloc_caches[kmalloc_type(flags)][index];
649}
650
651#ifdef CONFIG_ZONE_DMA
652#define INIT_KMALLOC_INFO(__size, __short_size) \
653{ \
654 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
655 .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
656 .name[KMALLOC_DMA] = "dma-kmalloc-" #__short_size, \
657 .size = __size, \
658}
659#else
660#define INIT_KMALLOC_INFO(__size, __short_size) \
661{ \
662 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
663 .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
664 .size = __size, \
665}
666#endif
667
668/*
669 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
670 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
671 * kmalloc-67108864.
672 */
673const struct kmalloc_info_struct kmalloc_info[] __initconst = {
674 INIT_KMALLOC_INFO(0, 0),
675 INIT_KMALLOC_INFO(96, 96),
676 INIT_KMALLOC_INFO(192, 192),
677 INIT_KMALLOC_INFO(8, 8),
678 INIT_KMALLOC_INFO(16, 16),
679 INIT_KMALLOC_INFO(32, 32),
680 INIT_KMALLOC_INFO(64, 64),
681 INIT_KMALLOC_INFO(128, 128),
682 INIT_KMALLOC_INFO(256, 256),
683 INIT_KMALLOC_INFO(512, 512),
684 INIT_KMALLOC_INFO(1024, 1k),
685 INIT_KMALLOC_INFO(2048, 2k),
686 INIT_KMALLOC_INFO(4096, 4k),
687 INIT_KMALLOC_INFO(8192, 8k),
688 INIT_KMALLOC_INFO(16384, 16k),
689 INIT_KMALLOC_INFO(32768, 32k),
690 INIT_KMALLOC_INFO(65536, 64k),
691 INIT_KMALLOC_INFO(131072, 128k),
692 INIT_KMALLOC_INFO(262144, 256k),
693 INIT_KMALLOC_INFO(524288, 512k),
694 INIT_KMALLOC_INFO(1048576, 1M),
695 INIT_KMALLOC_INFO(2097152, 2M),
696 INIT_KMALLOC_INFO(4194304, 4M),
697 INIT_KMALLOC_INFO(8388608, 8M),
698 INIT_KMALLOC_INFO(16777216, 16M),
699 INIT_KMALLOC_INFO(33554432, 32M),
700 INIT_KMALLOC_INFO(67108864, 64M)
701};
702
703/*
704 * Patch up the size_index table if we have strange large alignment
705 * requirements for the kmalloc array. This is only the case for
706 * MIPS it seems. The standard arches will not generate any code here.
707 *
708 * Largest permitted alignment is 256 bytes due to the way we
709 * handle the index determination for the smaller caches.
710 *
711 * Make sure that nothing crazy happens if someone starts tinkering
712 * around with ARCH_KMALLOC_MINALIGN
713 */
714void __init setup_kmalloc_cache_index_table(void)
715{
716 unsigned int i;
717
718 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
719 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
720
721 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
722 unsigned int elem = size_index_elem(i);
723
724 if (elem >= ARRAY_SIZE(size_index))
725 break;
726 size_index[elem] = KMALLOC_SHIFT_LOW;
727 }
728
729 if (KMALLOC_MIN_SIZE >= 64) {
730 /*
731 * The 96 byte size cache is not used if the alignment
732 * is 64 byte.
733 */
734 for (i = 64 + 8; i <= 96; i += 8)
735 size_index[size_index_elem(i)] = 7;
736
737 }
738
739 if (KMALLOC_MIN_SIZE >= 128) {
740 /*
741 * The 192 byte sized cache is not used if the alignment
742 * is 128 byte. Redirect kmalloc to use the 256 byte cache
743 * instead.
744 */
745 for (i = 128 + 8; i <= 192; i += 8)
746 size_index[size_index_elem(i)] = 8;
747 }
748}
749
750static void __init
751new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
752{
753 if (type == KMALLOC_RECLAIM)
754 flags |= SLAB_RECLAIM_ACCOUNT;
755
756 kmalloc_caches[type][idx] = create_kmalloc_cache(
757 kmalloc_info[idx].name[type],
758 kmalloc_info[idx].size, flags, 0,
759 kmalloc_info[idx].size);
760}
761
762/*
763 * Create the kmalloc array. Some of the regular kmalloc arrays
764 * may already have been created because they were needed to
765 * enable allocations for slab creation.
766 */
767void __init create_kmalloc_caches(slab_flags_t flags)
768{
769 int i;
770 enum kmalloc_cache_type type;
771
772 for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
773 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
774 if (!kmalloc_caches[type][i])
775 new_kmalloc_cache(i, type, flags);
776
777 /*
778 * Caches that are not of the two-to-the-power-of size.
779 * These have to be created immediately after the
780 * earlier power of two caches
781 */
782 if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
783 !kmalloc_caches[type][1])
784 new_kmalloc_cache(1, type, flags);
785 if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
786 !kmalloc_caches[type][2])
787 new_kmalloc_cache(2, type, flags);
788 }
789 }
790
791 /* Kmalloc array is now usable */
792 slab_state = UP;
793
794#ifdef CONFIG_ZONE_DMA
795 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
796 struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
797
798 if (s) {
799 kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
800 kmalloc_info[i].name[KMALLOC_DMA],
801 kmalloc_info[i].size,
802 SLAB_CACHE_DMA | flags, 0,
803 kmalloc_info[i].size);
804 }
805 }
806#endif
807}
808#endif /* !CONFIG_SLOB */
809
810gfp_t kmalloc_fix_flags(gfp_t flags)
811{
812 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
813
814 flags &= ~GFP_SLAB_BUG_MASK;
815 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
816 invalid_mask, &invalid_mask, flags, &flags);
817 dump_stack();
818
819 return flags;
820}
821
822/*
823 * To avoid unnecessary overhead, we pass through large allocation requests
824 * directly to the page allocator. We use __GFP_COMP, because we will need to
825 * know the allocation order to free the pages properly in kfree.
826 */
827void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
828{
829 void *ret = NULL;
830 struct page *page;
831
832 if (unlikely(flags & GFP_SLAB_BUG_MASK))
833 flags = kmalloc_fix_flags(flags);
834
835 flags |= __GFP_COMP;
836 page = alloc_pages(flags, order);
837 if (likely(page)) {
838 ret = page_address(page);
839 mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
840 PAGE_SIZE << order);
841 }
842 ret = kasan_kmalloc_large(ret, size, flags);
843 /* As ret might get tagged, call kmemleak hook after KASAN. */
844 kmemleak_alloc(ret, size, 1, flags);
845 return ret;
846}
847EXPORT_SYMBOL(kmalloc_order);
848
849#ifdef CONFIG_TRACING
850void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
851{
852 void *ret = kmalloc_order(size, flags, order);
853 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
854 return ret;
855}
856EXPORT_SYMBOL(kmalloc_order_trace);
857#endif
858
859#ifdef CONFIG_SLAB_FREELIST_RANDOM
860/* Randomize a generic freelist */
861static void freelist_randomize(struct rnd_state *state, unsigned int *list,
862 unsigned int count)
863{
864 unsigned int rand;
865 unsigned int i;
866
867 for (i = 0; i < count; i++)
868 list[i] = i;
869
870 /* Fisher-Yates shuffle */
871 for (i = count - 1; i > 0; i--) {
872 rand = prandom_u32_state(state);
873 rand %= (i + 1);
874 swap(list[i], list[rand]);
875 }
876}
877
878/* Create a random sequence per cache */
879int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
880 gfp_t gfp)
881{
882 struct rnd_state state;
883
884 if (count < 2 || cachep->random_seq)
885 return 0;
886
887 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
888 if (!cachep->random_seq)
889 return -ENOMEM;
890
891 /* Get best entropy at this stage of boot */
892 prandom_seed_state(&state, get_random_long());
893
894 freelist_randomize(&state, cachep->random_seq, count);
895 return 0;
896}
897
898/* Destroy the per-cache random freelist sequence */
899void cache_random_seq_destroy(struct kmem_cache *cachep)
900{
901 kfree(cachep->random_seq);
902 cachep->random_seq = NULL;
903}
904#endif /* CONFIG_SLAB_FREELIST_RANDOM */
905
906#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
907#ifdef CONFIG_SLAB
908#define SLABINFO_RIGHTS (0600)
909#else
910#define SLABINFO_RIGHTS (0400)
911#endif
912
913static void print_slabinfo_header(struct seq_file *m)
914{
915 /*
916 * Output format version, so at least we can change it
917 * without _too_ many complaints.
918 */
919#ifdef CONFIG_DEBUG_SLAB
920 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
921#else
922 seq_puts(m, "slabinfo - version: 2.1\n");
923#endif
924 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
925 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
926 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
927#ifdef CONFIG_DEBUG_SLAB
928 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
929 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
930#endif
931 seq_putc(m, '\n');
932}
933
934void *slab_start(struct seq_file *m, loff_t *pos)
935{
936 mutex_lock(&slab_mutex);
937 return seq_list_start(&slab_caches, *pos);
938}
939
940void *slab_next(struct seq_file *m, void *p, loff_t *pos)
941{
942 return seq_list_next(p, &slab_caches, pos);
943}
944
945void slab_stop(struct seq_file *m, void *p)
946{
947 mutex_unlock(&slab_mutex);
948}
949
950static void cache_show(struct kmem_cache *s, struct seq_file *m)
951{
952 struct slabinfo sinfo;
953
954 memset(&sinfo, 0, sizeof(sinfo));
955 get_slabinfo(s, &sinfo);
956
957 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
958 s->name, sinfo.active_objs, sinfo.num_objs, s->size,
959 sinfo.objects_per_slab, (1 << sinfo.cache_order));
960
961 seq_printf(m, " : tunables %4u %4u %4u",
962 sinfo.limit, sinfo.batchcount, sinfo.shared);
963 seq_printf(m, " : slabdata %6lu %6lu %6lu",
964 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
965 slabinfo_show_stats(m, s);
966 seq_putc(m, '\n');
967}
968
969static int slab_show(struct seq_file *m, void *p)
970{
971 struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
972
973 if (p == slab_caches.next)
974 print_slabinfo_header(m);
975 cache_show(s, m);
976 return 0;
977}
978
979void dump_unreclaimable_slab(void)
980{
981 struct kmem_cache *s, *s2;
982 struct slabinfo sinfo;
983
984 /*
985 * Here acquiring slab_mutex is risky since we don't prefer to get
986 * sleep in oom path. But, without mutex hold, it may introduce a
987 * risk of crash.
988 * Use mutex_trylock to protect the list traverse, dump nothing
989 * without acquiring the mutex.
990 */
991 if (!mutex_trylock(&slab_mutex)) {
992 pr_warn("excessive unreclaimable slab but cannot dump stats\n");
993 return;
994 }
995
996 pr_info("Unreclaimable slab info:\n");
997 pr_info("Name Used Total\n");
998
999 list_for_each_entry_safe(s, s2, &slab_caches, list) {
1000 if (s->flags & SLAB_RECLAIM_ACCOUNT)
1001 continue;
1002
1003 get_slabinfo(s, &sinfo);
1004
1005 if (sinfo.num_objs > 0)
1006 pr_info("%-17s %10luKB %10luKB\n", s->name,
1007 (sinfo.active_objs * s->size) / 1024,
1008 (sinfo.num_objs * s->size) / 1024);
1009 }
1010 mutex_unlock(&slab_mutex);
1011}
1012
1013#if defined(CONFIG_MEMCG_KMEM)
1014int memcg_slab_show(struct seq_file *m, void *p)
1015{
1016 /*
1017 * Deprecated.
1018 * Please, take a look at tools/cgroup/slabinfo.py .
1019 */
1020 return 0;
1021}
1022#endif
1023
1024/*
1025 * slabinfo_op - iterator that generates /proc/slabinfo
1026 *
1027 * Output layout:
1028 * cache-name
1029 * num-active-objs
1030 * total-objs
1031 * object size
1032 * num-active-slabs
1033 * total-slabs
1034 * num-pages-per-slab
1035 * + further values on SMP and with statistics enabled
1036 */
1037static const struct seq_operations slabinfo_op = {
1038 .start = slab_start,
1039 .next = slab_next,
1040 .stop = slab_stop,
1041 .show = slab_show,
1042};
1043
1044static int slabinfo_open(struct inode *inode, struct file *file)
1045{
1046 return seq_open(file, &slabinfo_op);
1047}
1048
1049static const struct proc_ops slabinfo_proc_ops = {
1050 .proc_flags = PROC_ENTRY_PERMANENT,
1051 .proc_open = slabinfo_open,
1052 .proc_read = seq_read,
1053 .proc_write = slabinfo_write,
1054 .proc_lseek = seq_lseek,
1055 .proc_release = seq_release,
1056};
1057
1058static int __init slab_proc_init(void)
1059{
1060 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
1061 return 0;
1062}
1063module_init(slab_proc_init);
1064
1065#endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
1066
1067static __always_inline void *__do_krealloc(const void *p, size_t new_size,
1068 gfp_t flags)
1069{
1070 void *ret;
1071 size_t ks;
1072
1073 ks = ksize(p);
1074
1075 if (ks >= new_size) {
1076 p = kasan_krealloc((void *)p, new_size, flags);
1077 return (void *)p;
1078 }
1079
1080 ret = kmalloc_track_caller(new_size, flags);
1081 if (ret && p)
1082 memcpy(ret, p, ks);
1083
1084 return ret;
1085}
1086
1087/**
1088 * krealloc - reallocate memory. The contents will remain unchanged.
1089 * @p: object to reallocate memory for.
1090 * @new_size: how many bytes of memory are required.
1091 * @flags: the type of memory to allocate.
1092 *
1093 * The contents of the object pointed to are preserved up to the
1094 * lesser of the new and old sizes. If @p is %NULL, krealloc()
1095 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
1096 * %NULL pointer, the object pointed to is freed.
1097 *
1098 * Return: pointer to the allocated memory or %NULL in case of error
1099 */
1100void *krealloc(const void *p, size_t new_size, gfp_t flags)
1101{
1102 void *ret;
1103
1104 if (unlikely(!new_size)) {
1105 kfree(p);
1106 return ZERO_SIZE_PTR;
1107 }
1108
1109 ret = __do_krealloc(p, new_size, flags);
1110 if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
1111 kfree(p);
1112
1113 return ret;
1114}
1115EXPORT_SYMBOL(krealloc);
1116
1117/**
1118 * kfree_sensitive - Clear sensitive information in memory before freeing
1119 * @p: object to free memory of
1120 *
1121 * The memory of the object @p points to is zeroed before freed.
1122 * If @p is %NULL, kfree_sensitive() does nothing.
1123 *
1124 * Note: this function zeroes the whole allocated buffer which can be a good
1125 * deal bigger than the requested buffer size passed to kmalloc(). So be
1126 * careful when using this function in performance sensitive code.
1127 */
1128void kfree_sensitive(const void *p)
1129{
1130 size_t ks;
1131 void *mem = (void *)p;
1132
1133 ks = ksize(mem);
1134 if (ks)
1135 memzero_explicit(mem, ks);
1136 kfree(mem);
1137}
1138EXPORT_SYMBOL(kfree_sensitive);
1139
1140/**
1141 * ksize - get the actual amount of memory allocated for a given object
1142 * @objp: Pointer to the object
1143 *
1144 * kmalloc may internally round up allocations and return more memory
1145 * than requested. ksize() can be used to determine the actual amount of
1146 * memory allocated. The caller may use this additional memory, even though
1147 * a smaller amount of memory was initially specified with the kmalloc call.
1148 * The caller must guarantee that objp points to a valid object previously
1149 * allocated with either kmalloc() or kmem_cache_alloc(). The object
1150 * must not be freed during the duration of the call.
1151 *
1152 * Return: size of the actual memory used by @objp in bytes
1153 */
1154size_t ksize(const void *objp)
1155{
1156 size_t size;
1157
1158 /*
1159 * We need to check that the pointed to object is valid, and only then
1160 * unpoison the shadow memory below. We use __kasan_check_read(), to
1161 * generate a more useful report at the time ksize() is called (rather
1162 * than later where behaviour is undefined due to potential
1163 * use-after-free or double-free).
1164 *
1165 * If the pointed to memory is invalid we return 0, to avoid users of
1166 * ksize() writing to and potentially corrupting the memory region.
1167 *
1168 * We want to perform the check before __ksize(), to avoid potentially
1169 * crashing in __ksize() due to accessing invalid metadata.
1170 */
1171 if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1))
1172 return 0;
1173
1174 size = __ksize(objp);
1175 /*
1176 * We assume that ksize callers could use whole allocated area,
1177 * so we need to unpoison this area.
1178 */
1179 kasan_unpoison_shadow(objp, size);
1180 return size;
1181}
1182EXPORT_SYMBOL(ksize);
1183
1184/* Tracepoints definitions. */
1185EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1186EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1187EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
1188EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
1189EXPORT_TRACEPOINT_SYMBOL(kfree);
1190EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1191
1192int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
1193{
1194 if (__should_failslab(s, gfpflags))
1195 return -ENOMEM;
1196 return 0;
1197}
1198ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Slab allocator functions that are independent of the allocator strategy
4 *
5 * (C) 2012 Christoph Lameter <cl@linux.com>
6 */
7#include <linux/slab.h>
8
9#include <linux/mm.h>
10#include <linux/poison.h>
11#include <linux/interrupt.h>
12#include <linux/memory.h>
13#include <linux/cache.h>
14#include <linux/compiler.h>
15#include <linux/kfence.h>
16#include <linux/module.h>
17#include <linux/cpu.h>
18#include <linux/uaccess.h>
19#include <linux/seq_file.h>
20#include <linux/dma-mapping.h>
21#include <linux/swiotlb.h>
22#include <linux/proc_fs.h>
23#include <linux/debugfs.h>
24#include <linux/kmemleak.h>
25#include <linux/kasan.h>
26#include <asm/cacheflush.h>
27#include <asm/tlbflush.h>
28#include <asm/page.h>
29#include <linux/memcontrol.h>
30#include <linux/stackdepot.h>
31
32#include "internal.h"
33#include "slab.h"
34
35#define CREATE_TRACE_POINTS
36#include <trace/events/kmem.h>
37
38enum slab_state slab_state;
39LIST_HEAD(slab_caches);
40DEFINE_MUTEX(slab_mutex);
41struct kmem_cache *kmem_cache;
42
43/*
44 * Set of flags that will prevent slab merging
45 */
46#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
47 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
48 SLAB_FAILSLAB | SLAB_NO_MERGE)
49
50#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
51 SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
52
53/*
54 * Merge control. If this is set then no merging of slab caches will occur.
55 */
56static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
57
58static int __init setup_slab_nomerge(char *str)
59{
60 slab_nomerge = true;
61 return 1;
62}
63
64static int __init setup_slab_merge(char *str)
65{
66 slab_nomerge = false;
67 return 1;
68}
69
70__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
71__setup_param("slub_merge", slub_merge, setup_slab_merge, 0);
72
73__setup("slab_nomerge", setup_slab_nomerge);
74__setup("slab_merge", setup_slab_merge);
75
76/*
77 * Determine the size of a slab object
78 */
79unsigned int kmem_cache_size(struct kmem_cache *s)
80{
81 return s->object_size;
82}
83EXPORT_SYMBOL(kmem_cache_size);
84
85#ifdef CONFIG_DEBUG_VM
86
87static bool kmem_cache_is_duplicate_name(const char *name)
88{
89 struct kmem_cache *s;
90
91 list_for_each_entry(s, &slab_caches, list) {
92 if (!strcmp(s->name, name))
93 return true;
94 }
95
96 return false;
97}
98
99static int kmem_cache_sanity_check(const char *name, unsigned int size)
100{
101 if (!name || in_interrupt() || size > KMALLOC_MAX_SIZE) {
102 pr_err("kmem_cache_create(%s) integrity check failed\n", name);
103 return -EINVAL;
104 }
105
106 /* Duplicate names will confuse slabtop, et al */
107 WARN(kmem_cache_is_duplicate_name(name),
108 "kmem_cache of name '%s' already exists\n", name);
109
110 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
111 return 0;
112}
113#else
114static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
115{
116 return 0;
117}
118#endif
119
120/*
121 * Figure out what the alignment of the objects will be given a set of
122 * flags, a user specified alignment and the size of the objects.
123 */
124static unsigned int calculate_alignment(slab_flags_t flags,
125 unsigned int align, unsigned int size)
126{
127 /*
128 * If the user wants hardware cache aligned objects then follow that
129 * suggestion if the object is sufficiently large.
130 *
131 * The hardware cache alignment cannot override the specified
132 * alignment though. If that is greater then use it.
133 */
134 if (flags & SLAB_HWCACHE_ALIGN) {
135 unsigned int ralign;
136
137 ralign = cache_line_size();
138 while (size <= ralign / 2)
139 ralign /= 2;
140 align = max(align, ralign);
141 }
142
143 align = max(align, arch_slab_minalign());
144
145 return ALIGN(align, sizeof(void *));
146}
147
148/*
149 * Find a mergeable slab cache
150 */
151int slab_unmergeable(struct kmem_cache *s)
152{
153 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
154 return 1;
155
156 if (s->ctor)
157 return 1;
158
159#ifdef CONFIG_HARDENED_USERCOPY
160 if (s->usersize)
161 return 1;
162#endif
163
164 /*
165 * We may have set a slab to be unmergeable during bootstrap.
166 */
167 if (s->refcount < 0)
168 return 1;
169
170 return 0;
171}
172
173struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
174 slab_flags_t flags, const char *name, void (*ctor)(void *))
175{
176 struct kmem_cache *s;
177
178 if (slab_nomerge)
179 return NULL;
180
181 if (ctor)
182 return NULL;
183
184 flags = kmem_cache_flags(flags, name);
185
186 if (flags & SLAB_NEVER_MERGE)
187 return NULL;
188
189 size = ALIGN(size, sizeof(void *));
190 align = calculate_alignment(flags, align, size);
191 size = ALIGN(size, align);
192
193 list_for_each_entry_reverse(s, &slab_caches, list) {
194 if (slab_unmergeable(s))
195 continue;
196
197 if (size > s->size)
198 continue;
199
200 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
201 continue;
202 /*
203 * Check if alignment is compatible.
204 * Courtesy of Adrian Drzewiecki
205 */
206 if ((s->size & ~(align - 1)) != s->size)
207 continue;
208
209 if (s->size - size >= sizeof(void *))
210 continue;
211
212 return s;
213 }
214 return NULL;
215}
216
217static struct kmem_cache *create_cache(const char *name,
218 unsigned int object_size,
219 struct kmem_cache_args *args,
220 slab_flags_t flags)
221{
222 struct kmem_cache *s;
223 int err;
224
225 /* If a custom freelist pointer is requested make sure it's sane. */
226 err = -EINVAL;
227 if (args->use_freeptr_offset &&
228 (args->freeptr_offset >= object_size ||
229 !(flags & SLAB_TYPESAFE_BY_RCU) ||
230 !IS_ALIGNED(args->freeptr_offset, __alignof__(freeptr_t))))
231 goto out;
232
233 err = -ENOMEM;
234 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
235 if (!s)
236 goto out;
237 err = do_kmem_cache_create(s, name, object_size, args, flags);
238 if (err)
239 goto out_free_cache;
240
241 s->refcount = 1;
242 list_add(&s->list, &slab_caches);
243 return s;
244
245out_free_cache:
246 kmem_cache_free(kmem_cache, s);
247out:
248 return ERR_PTR(err);
249}
250
251/**
252 * __kmem_cache_create_args - Create a kmem cache.
253 * @name: A string which is used in /proc/slabinfo to identify this cache.
254 * @object_size: The size of objects to be created in this cache.
255 * @args: Additional arguments for the cache creation (see
256 * &struct kmem_cache_args).
257 * @flags: See the desriptions of individual flags. The common ones are listed
258 * in the description below.
259 *
260 * Not to be called directly, use the kmem_cache_create() wrapper with the same
261 * parameters.
262 *
263 * Commonly used @flags:
264 *
265 * &SLAB_ACCOUNT - Account allocations to memcg.
266 *
267 * &SLAB_HWCACHE_ALIGN - Align objects on cache line boundaries.
268 *
269 * &SLAB_RECLAIM_ACCOUNT - Objects are reclaimable.
270 *
271 * &SLAB_TYPESAFE_BY_RCU - Slab page (not individual objects) freeing delayed
272 * by a grace period - see the full description before using.
273 *
274 * Context: Cannot be called within a interrupt, but can be interrupted.
275 *
276 * Return: a pointer to the cache on success, NULL on failure.
277 */
278struct kmem_cache *__kmem_cache_create_args(const char *name,
279 unsigned int object_size,
280 struct kmem_cache_args *args,
281 slab_flags_t flags)
282{
283 struct kmem_cache *s = NULL;
284 const char *cache_name;
285 int err;
286
287#ifdef CONFIG_SLUB_DEBUG
288 /*
289 * If no slab_debug was enabled globally, the static key is not yet
290 * enabled by setup_slub_debug(). Enable it if the cache is being
291 * created with any of the debugging flags passed explicitly.
292 * It's also possible that this is the first cache created with
293 * SLAB_STORE_USER and we should init stack_depot for it.
294 */
295 if (flags & SLAB_DEBUG_FLAGS)
296 static_branch_enable(&slub_debug_enabled);
297 if (flags & SLAB_STORE_USER)
298 stack_depot_init();
299#endif
300
301 mutex_lock(&slab_mutex);
302
303 err = kmem_cache_sanity_check(name, object_size);
304 if (err) {
305 goto out_unlock;
306 }
307
308 /* Refuse requests with allocator specific flags */
309 if (flags & ~SLAB_FLAGS_PERMITTED) {
310 err = -EINVAL;
311 goto out_unlock;
312 }
313
314 /*
315 * Some allocators will constraint the set of valid flags to a subset
316 * of all flags. We expect them to define CACHE_CREATE_MASK in this
317 * case, and we'll just provide them with a sanitized version of the
318 * passed flags.
319 */
320 flags &= CACHE_CREATE_MASK;
321
322 /* Fail closed on bad usersize of useroffset values. */
323 if (!IS_ENABLED(CONFIG_HARDENED_USERCOPY) ||
324 WARN_ON(!args->usersize && args->useroffset) ||
325 WARN_ON(object_size < args->usersize ||
326 object_size - args->usersize < args->useroffset))
327 args->usersize = args->useroffset = 0;
328
329 if (!args->usersize)
330 s = __kmem_cache_alias(name, object_size, args->align, flags,
331 args->ctor);
332 if (s)
333 goto out_unlock;
334
335 cache_name = kstrdup_const(name, GFP_KERNEL);
336 if (!cache_name) {
337 err = -ENOMEM;
338 goto out_unlock;
339 }
340
341 args->align = calculate_alignment(flags, args->align, object_size);
342 s = create_cache(cache_name, object_size, args, flags);
343 if (IS_ERR(s)) {
344 err = PTR_ERR(s);
345 kfree_const(cache_name);
346 }
347
348out_unlock:
349 mutex_unlock(&slab_mutex);
350
351 if (err) {
352 if (flags & SLAB_PANIC)
353 panic("%s: Failed to create slab '%s'. Error %d\n",
354 __func__, name, err);
355 else {
356 pr_warn("%s(%s) failed with error %d\n",
357 __func__, name, err);
358 dump_stack();
359 }
360 return NULL;
361 }
362 return s;
363}
364EXPORT_SYMBOL(__kmem_cache_create_args);
365
366static struct kmem_cache *kmem_buckets_cache __ro_after_init;
367
368/**
369 * kmem_buckets_create - Create a set of caches that handle dynamic sized
370 * allocations via kmem_buckets_alloc()
371 * @name: A prefix string which is used in /proc/slabinfo to identify this
372 * cache. The individual caches with have their sizes as the suffix.
373 * @flags: SLAB flags (see kmem_cache_create() for details).
374 * @useroffset: Starting offset within an allocation that may be copied
375 * to/from userspace.
376 * @usersize: How many bytes, starting at @useroffset, may be copied
377 * to/from userspace.
378 * @ctor: A constructor for the objects, run when new allocations are made.
379 *
380 * Cannot be called within an interrupt, but can be interrupted.
381 *
382 * Return: a pointer to the cache on success, NULL on failure. When
383 * CONFIG_SLAB_BUCKETS is not enabled, ZERO_SIZE_PTR is returned, and
384 * subsequent calls to kmem_buckets_alloc() will fall back to kmalloc().
385 * (i.e. callers only need to check for NULL on failure.)
386 */
387kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags,
388 unsigned int useroffset,
389 unsigned int usersize,
390 void (*ctor)(void *))
391{
392 unsigned long mask = 0;
393 unsigned int idx;
394 kmem_buckets *b;
395
396 BUILD_BUG_ON(ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]) > BITS_PER_LONG);
397
398 /*
399 * When the separate buckets API is not built in, just return
400 * a non-NULL value for the kmem_buckets pointer, which will be
401 * unused when performing allocations.
402 */
403 if (!IS_ENABLED(CONFIG_SLAB_BUCKETS))
404 return ZERO_SIZE_PTR;
405
406 if (WARN_ON(!kmem_buckets_cache))
407 return NULL;
408
409 b = kmem_cache_alloc(kmem_buckets_cache, GFP_KERNEL|__GFP_ZERO);
410 if (WARN_ON(!b))
411 return NULL;
412
413 flags |= SLAB_NO_MERGE;
414
415 for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) {
416 char *short_size, *cache_name;
417 unsigned int cache_useroffset, cache_usersize;
418 unsigned int size, aligned_idx;
419
420 if (!kmalloc_caches[KMALLOC_NORMAL][idx])
421 continue;
422
423 size = kmalloc_caches[KMALLOC_NORMAL][idx]->object_size;
424 if (!size)
425 continue;
426
427 short_size = strchr(kmalloc_caches[KMALLOC_NORMAL][idx]->name, '-');
428 if (WARN_ON(!short_size))
429 goto fail;
430
431 if (useroffset >= size) {
432 cache_useroffset = 0;
433 cache_usersize = 0;
434 } else {
435 cache_useroffset = useroffset;
436 cache_usersize = min(size - cache_useroffset, usersize);
437 }
438
439 aligned_idx = __kmalloc_index(size, false);
440 if (!(*b)[aligned_idx]) {
441 cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1);
442 if (WARN_ON(!cache_name))
443 goto fail;
444 (*b)[aligned_idx] = kmem_cache_create_usercopy(cache_name, size,
445 0, flags, cache_useroffset,
446 cache_usersize, ctor);
447 kfree(cache_name);
448 if (WARN_ON(!(*b)[aligned_idx]))
449 goto fail;
450 set_bit(aligned_idx, &mask);
451 }
452 if (idx != aligned_idx)
453 (*b)[idx] = (*b)[aligned_idx];
454 }
455
456 return b;
457
458fail:
459 for_each_set_bit(idx, &mask, ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]))
460 kmem_cache_destroy((*b)[idx]);
461 kmem_cache_free(kmem_buckets_cache, b);
462
463 return NULL;
464}
465EXPORT_SYMBOL(kmem_buckets_create);
466
467/*
468 * For a given kmem_cache, kmem_cache_destroy() should only be called
469 * once or there will be a use-after-free problem. The actual deletion
470 * and release of the kobject does not need slab_mutex or cpu_hotplug_lock
471 * protection. So they are now done without holding those locks.
472 */
473static void kmem_cache_release(struct kmem_cache *s)
474{
475 kfence_shutdown_cache(s);
476 if (__is_defined(SLAB_SUPPORTS_SYSFS) && slab_state >= FULL)
477 sysfs_slab_release(s);
478 else
479 slab_kmem_cache_release(s);
480}
481
482void slab_kmem_cache_release(struct kmem_cache *s)
483{
484 __kmem_cache_release(s);
485 kfree_const(s->name);
486 kmem_cache_free(kmem_cache, s);
487}
488
489void kmem_cache_destroy(struct kmem_cache *s)
490{
491 int err;
492
493 if (unlikely(!s) || !kasan_check_byte(s))
494 return;
495
496 /* in-flight kfree_rcu()'s may include objects from our cache */
497 kvfree_rcu_barrier();
498
499 if (IS_ENABLED(CONFIG_SLUB_RCU_DEBUG) &&
500 (s->flags & SLAB_TYPESAFE_BY_RCU)) {
501 /*
502 * Under CONFIG_SLUB_RCU_DEBUG, when objects in a
503 * SLAB_TYPESAFE_BY_RCU slab are freed, SLUB will internally
504 * defer their freeing with call_rcu().
505 * Wait for such call_rcu() invocations here before actually
506 * destroying the cache.
507 *
508 * It doesn't matter that we haven't looked at the slab refcount
509 * yet - slabs with SLAB_TYPESAFE_BY_RCU can't be merged, so
510 * the refcount should be 1 here.
511 */
512 rcu_barrier();
513 }
514
515 cpus_read_lock();
516 mutex_lock(&slab_mutex);
517
518 s->refcount--;
519 if (s->refcount) {
520 mutex_unlock(&slab_mutex);
521 cpus_read_unlock();
522 return;
523 }
524
525 /* free asan quarantined objects */
526 kasan_cache_shutdown(s);
527
528 err = __kmem_cache_shutdown(s);
529 if (!slab_in_kunit_test())
530 WARN(err, "%s %s: Slab cache still has objects when called from %pS",
531 __func__, s->name, (void *)_RET_IP_);
532
533 list_del(&s->list);
534
535 mutex_unlock(&slab_mutex);
536 cpus_read_unlock();
537
538 if (slab_state >= FULL)
539 sysfs_slab_unlink(s);
540 debugfs_slab_release(s);
541
542 if (err)
543 return;
544
545 if (s->flags & SLAB_TYPESAFE_BY_RCU)
546 rcu_barrier();
547
548 kmem_cache_release(s);
549}
550EXPORT_SYMBOL(kmem_cache_destroy);
551
552/**
553 * kmem_cache_shrink - Shrink a cache.
554 * @cachep: The cache to shrink.
555 *
556 * Releases as many slabs as possible for a cache.
557 * To help debugging, a zero exit status indicates all slabs were released.
558 *
559 * Return: %0 if all slabs were released, non-zero otherwise
560 */
561int kmem_cache_shrink(struct kmem_cache *cachep)
562{
563 kasan_cache_shrink(cachep);
564
565 return __kmem_cache_shrink(cachep);
566}
567EXPORT_SYMBOL(kmem_cache_shrink);
568
569bool slab_is_available(void)
570{
571 return slab_state >= UP;
572}
573
574#ifdef CONFIG_PRINTK
575static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
576{
577 if (__kfence_obj_info(kpp, object, slab))
578 return;
579 __kmem_obj_info(kpp, object, slab);
580}
581
582/**
583 * kmem_dump_obj - Print available slab provenance information
584 * @object: slab object for which to find provenance information.
585 *
586 * This function uses pr_cont(), so that the caller is expected to have
587 * printed out whatever preamble is appropriate. The provenance information
588 * depends on the type of object and on how much debugging is enabled.
589 * For a slab-cache object, the fact that it is a slab object is printed,
590 * and, if available, the slab name, return address, and stack trace from
591 * the allocation and last free path of that object.
592 *
593 * Return: %true if the pointer is to a not-yet-freed object from
594 * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer
595 * is to an already-freed object, and %false otherwise.
596 */
597bool kmem_dump_obj(void *object)
598{
599 char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
600 int i;
601 struct slab *slab;
602 unsigned long ptroffset;
603 struct kmem_obj_info kp = { };
604
605 /* Some arches consider ZERO_SIZE_PTR to be a valid address. */
606 if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
607 return false;
608 slab = virt_to_slab(object);
609 if (!slab)
610 return false;
611
612 kmem_obj_info(&kp, object, slab);
613 if (kp.kp_slab_cache)
614 pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name);
615 else
616 pr_cont(" slab%s", cp);
617 if (is_kfence_address(object))
618 pr_cont(" (kfence)");
619 if (kp.kp_objp)
620 pr_cont(" start %px", kp.kp_objp);
621 if (kp.kp_data_offset)
622 pr_cont(" data offset %lu", kp.kp_data_offset);
623 if (kp.kp_objp) {
624 ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset;
625 pr_cont(" pointer offset %lu", ptroffset);
626 }
627 if (kp.kp_slab_cache && kp.kp_slab_cache->object_size)
628 pr_cont(" size %u", kp.kp_slab_cache->object_size);
629 if (kp.kp_ret)
630 pr_cont(" allocated at %pS\n", kp.kp_ret);
631 else
632 pr_cont("\n");
633 for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) {
634 if (!kp.kp_stack[i])
635 break;
636 pr_info(" %pS\n", kp.kp_stack[i]);
637 }
638
639 if (kp.kp_free_stack[0])
640 pr_cont(" Free path:\n");
641
642 for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) {
643 if (!kp.kp_free_stack[i])
644 break;
645 pr_info(" %pS\n", kp.kp_free_stack[i]);
646 }
647
648 return true;
649}
650EXPORT_SYMBOL_GPL(kmem_dump_obj);
651#endif
652
653/* Create a cache during boot when no slab services are available yet */
654void __init create_boot_cache(struct kmem_cache *s, const char *name,
655 unsigned int size, slab_flags_t flags,
656 unsigned int useroffset, unsigned int usersize)
657{
658 int err;
659 unsigned int align = ARCH_KMALLOC_MINALIGN;
660 struct kmem_cache_args kmem_args = {};
661
662 /*
663 * kmalloc caches guarantee alignment of at least the largest
664 * power-of-two divisor of the size. For power-of-two sizes,
665 * it is the size itself.
666 */
667 if (flags & SLAB_KMALLOC)
668 align = max(align, 1U << (ffs(size) - 1));
669 kmem_args.align = calculate_alignment(flags, align, size);
670
671#ifdef CONFIG_HARDENED_USERCOPY
672 kmem_args.useroffset = useroffset;
673 kmem_args.usersize = usersize;
674#endif
675
676 err = do_kmem_cache_create(s, name, size, &kmem_args, flags);
677
678 if (err)
679 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
680 name, size, err);
681
682 s->refcount = -1; /* Exempt from merging for now */
683}
684
685static struct kmem_cache *__init create_kmalloc_cache(const char *name,
686 unsigned int size,
687 slab_flags_t flags)
688{
689 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
690
691 if (!s)
692 panic("Out of memory when creating slab %s\n", name);
693
694 create_boot_cache(s, name, size, flags | SLAB_KMALLOC, 0, size);
695 list_add(&s->list, &slab_caches);
696 s->refcount = 1;
697 return s;
698}
699
700kmem_buckets kmalloc_caches[NR_KMALLOC_TYPES] __ro_after_init =
701{ /* initialization for https://llvm.org/pr42570 */ };
702EXPORT_SYMBOL(kmalloc_caches);
703
704#ifdef CONFIG_RANDOM_KMALLOC_CACHES
705unsigned long random_kmalloc_seed __ro_after_init;
706EXPORT_SYMBOL(random_kmalloc_seed);
707#endif
708
709/*
710 * Conversion table for small slabs sizes / 8 to the index in the
711 * kmalloc array. This is necessary for slabs < 192 since we have non power
712 * of two cache sizes there. The size of larger slabs can be determined using
713 * fls.
714 */
715u8 kmalloc_size_index[24] __ro_after_init = {
716 3, /* 8 */
717 4, /* 16 */
718 5, /* 24 */
719 5, /* 32 */
720 6, /* 40 */
721 6, /* 48 */
722 6, /* 56 */
723 6, /* 64 */
724 1, /* 72 */
725 1, /* 80 */
726 1, /* 88 */
727 1, /* 96 */
728 7, /* 104 */
729 7, /* 112 */
730 7, /* 120 */
731 7, /* 128 */
732 2, /* 136 */
733 2, /* 144 */
734 2, /* 152 */
735 2, /* 160 */
736 2, /* 168 */
737 2, /* 176 */
738 2, /* 184 */
739 2 /* 192 */
740};
741
742size_t kmalloc_size_roundup(size_t size)
743{
744 if (size && size <= KMALLOC_MAX_CACHE_SIZE) {
745 /*
746 * The flags don't matter since size_index is common to all.
747 * Neither does the caller for just getting ->object_size.
748 */
749 return kmalloc_slab(size, NULL, GFP_KERNEL, 0)->object_size;
750 }
751
752 /* Above the smaller buckets, size is a multiple of page size. */
753 if (size && size <= KMALLOC_MAX_SIZE)
754 return PAGE_SIZE << get_order(size);
755
756 /*
757 * Return 'size' for 0 - kmalloc() returns ZERO_SIZE_PTR
758 * and very large size - kmalloc() may fail.
759 */
760 return size;
761
762}
763EXPORT_SYMBOL(kmalloc_size_roundup);
764
765#ifdef CONFIG_ZONE_DMA
766#define KMALLOC_DMA_NAME(sz) .name[KMALLOC_DMA] = "dma-kmalloc-" #sz,
767#else
768#define KMALLOC_DMA_NAME(sz)
769#endif
770
771#ifdef CONFIG_MEMCG
772#define KMALLOC_CGROUP_NAME(sz) .name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz,
773#else
774#define KMALLOC_CGROUP_NAME(sz)
775#endif
776
777#ifndef CONFIG_SLUB_TINY
778#define KMALLOC_RCL_NAME(sz) .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #sz,
779#else
780#define KMALLOC_RCL_NAME(sz)
781#endif
782
783#ifdef CONFIG_RANDOM_KMALLOC_CACHES
784#define __KMALLOC_RANDOM_CONCAT(a, b) a ## b
785#define KMALLOC_RANDOM_NAME(N, sz) __KMALLOC_RANDOM_CONCAT(KMA_RAND_, N)(sz)
786#define KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 1] = "kmalloc-rnd-01-" #sz,
787#define KMA_RAND_2(sz) KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 2] = "kmalloc-rnd-02-" #sz,
788#define KMA_RAND_3(sz) KMA_RAND_2(sz) .name[KMALLOC_RANDOM_START + 3] = "kmalloc-rnd-03-" #sz,
789#define KMA_RAND_4(sz) KMA_RAND_3(sz) .name[KMALLOC_RANDOM_START + 4] = "kmalloc-rnd-04-" #sz,
790#define KMA_RAND_5(sz) KMA_RAND_4(sz) .name[KMALLOC_RANDOM_START + 5] = "kmalloc-rnd-05-" #sz,
791#define KMA_RAND_6(sz) KMA_RAND_5(sz) .name[KMALLOC_RANDOM_START + 6] = "kmalloc-rnd-06-" #sz,
792#define KMA_RAND_7(sz) KMA_RAND_6(sz) .name[KMALLOC_RANDOM_START + 7] = "kmalloc-rnd-07-" #sz,
793#define KMA_RAND_8(sz) KMA_RAND_7(sz) .name[KMALLOC_RANDOM_START + 8] = "kmalloc-rnd-08-" #sz,
794#define KMA_RAND_9(sz) KMA_RAND_8(sz) .name[KMALLOC_RANDOM_START + 9] = "kmalloc-rnd-09-" #sz,
795#define KMA_RAND_10(sz) KMA_RAND_9(sz) .name[KMALLOC_RANDOM_START + 10] = "kmalloc-rnd-10-" #sz,
796#define KMA_RAND_11(sz) KMA_RAND_10(sz) .name[KMALLOC_RANDOM_START + 11] = "kmalloc-rnd-11-" #sz,
797#define KMA_RAND_12(sz) KMA_RAND_11(sz) .name[KMALLOC_RANDOM_START + 12] = "kmalloc-rnd-12-" #sz,
798#define KMA_RAND_13(sz) KMA_RAND_12(sz) .name[KMALLOC_RANDOM_START + 13] = "kmalloc-rnd-13-" #sz,
799#define KMA_RAND_14(sz) KMA_RAND_13(sz) .name[KMALLOC_RANDOM_START + 14] = "kmalloc-rnd-14-" #sz,
800#define KMA_RAND_15(sz) KMA_RAND_14(sz) .name[KMALLOC_RANDOM_START + 15] = "kmalloc-rnd-15-" #sz,
801#else // CONFIG_RANDOM_KMALLOC_CACHES
802#define KMALLOC_RANDOM_NAME(N, sz)
803#endif
804
805#define INIT_KMALLOC_INFO(__size, __short_size) \
806{ \
807 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
808 KMALLOC_RCL_NAME(__short_size) \
809 KMALLOC_CGROUP_NAME(__short_size) \
810 KMALLOC_DMA_NAME(__short_size) \
811 KMALLOC_RANDOM_NAME(RANDOM_KMALLOC_CACHES_NR, __short_size) \
812 .size = __size, \
813}
814
815/*
816 * kmalloc_info[] is to make slab_debug=,kmalloc-xx option work at boot time.
817 * kmalloc_index() supports up to 2^21=2MB, so the final entry of the table is
818 * kmalloc-2M.
819 */
820const struct kmalloc_info_struct kmalloc_info[] __initconst = {
821 INIT_KMALLOC_INFO(0, 0),
822 INIT_KMALLOC_INFO(96, 96),
823 INIT_KMALLOC_INFO(192, 192),
824 INIT_KMALLOC_INFO(8, 8),
825 INIT_KMALLOC_INFO(16, 16),
826 INIT_KMALLOC_INFO(32, 32),
827 INIT_KMALLOC_INFO(64, 64),
828 INIT_KMALLOC_INFO(128, 128),
829 INIT_KMALLOC_INFO(256, 256),
830 INIT_KMALLOC_INFO(512, 512),
831 INIT_KMALLOC_INFO(1024, 1k),
832 INIT_KMALLOC_INFO(2048, 2k),
833 INIT_KMALLOC_INFO(4096, 4k),
834 INIT_KMALLOC_INFO(8192, 8k),
835 INIT_KMALLOC_INFO(16384, 16k),
836 INIT_KMALLOC_INFO(32768, 32k),
837 INIT_KMALLOC_INFO(65536, 64k),
838 INIT_KMALLOC_INFO(131072, 128k),
839 INIT_KMALLOC_INFO(262144, 256k),
840 INIT_KMALLOC_INFO(524288, 512k),
841 INIT_KMALLOC_INFO(1048576, 1M),
842 INIT_KMALLOC_INFO(2097152, 2M)
843};
844
845/*
846 * Patch up the size_index table if we have strange large alignment
847 * requirements for the kmalloc array. This is only the case for
848 * MIPS it seems. The standard arches will not generate any code here.
849 *
850 * Largest permitted alignment is 256 bytes due to the way we
851 * handle the index determination for the smaller caches.
852 *
853 * Make sure that nothing crazy happens if someone starts tinkering
854 * around with ARCH_KMALLOC_MINALIGN
855 */
856void __init setup_kmalloc_cache_index_table(void)
857{
858 unsigned int i;
859
860 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
861 !is_power_of_2(KMALLOC_MIN_SIZE));
862
863 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
864 unsigned int elem = size_index_elem(i);
865
866 if (elem >= ARRAY_SIZE(kmalloc_size_index))
867 break;
868 kmalloc_size_index[elem] = KMALLOC_SHIFT_LOW;
869 }
870
871 if (KMALLOC_MIN_SIZE >= 64) {
872 /*
873 * The 96 byte sized cache is not used if the alignment
874 * is 64 byte.
875 */
876 for (i = 64 + 8; i <= 96; i += 8)
877 kmalloc_size_index[size_index_elem(i)] = 7;
878
879 }
880
881 if (KMALLOC_MIN_SIZE >= 128) {
882 /*
883 * The 192 byte sized cache is not used if the alignment
884 * is 128 byte. Redirect kmalloc to use the 256 byte cache
885 * instead.
886 */
887 for (i = 128 + 8; i <= 192; i += 8)
888 kmalloc_size_index[size_index_elem(i)] = 8;
889 }
890}
891
892static unsigned int __kmalloc_minalign(void)
893{
894 unsigned int minalign = dma_get_cache_alignment();
895
896 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) &&
897 is_swiotlb_allocated())
898 minalign = ARCH_KMALLOC_MINALIGN;
899
900 return max(minalign, arch_slab_minalign());
901}
902
903static void __init
904new_kmalloc_cache(int idx, enum kmalloc_cache_type type)
905{
906 slab_flags_t flags = 0;
907 unsigned int minalign = __kmalloc_minalign();
908 unsigned int aligned_size = kmalloc_info[idx].size;
909 int aligned_idx = idx;
910
911 if ((KMALLOC_RECLAIM != KMALLOC_NORMAL) && (type == KMALLOC_RECLAIM)) {
912 flags |= SLAB_RECLAIM_ACCOUNT;
913 } else if (IS_ENABLED(CONFIG_MEMCG) && (type == KMALLOC_CGROUP)) {
914 if (mem_cgroup_kmem_disabled()) {
915 kmalloc_caches[type][idx] = kmalloc_caches[KMALLOC_NORMAL][idx];
916 return;
917 }
918 flags |= SLAB_ACCOUNT;
919 } else if (IS_ENABLED(CONFIG_ZONE_DMA) && (type == KMALLOC_DMA)) {
920 flags |= SLAB_CACHE_DMA;
921 }
922
923#ifdef CONFIG_RANDOM_KMALLOC_CACHES
924 if (type >= KMALLOC_RANDOM_START && type <= KMALLOC_RANDOM_END)
925 flags |= SLAB_NO_MERGE;
926#endif
927
928 /*
929 * If CONFIG_MEMCG is enabled, disable cache merging for
930 * KMALLOC_NORMAL caches.
931 */
932 if (IS_ENABLED(CONFIG_MEMCG) && (type == KMALLOC_NORMAL))
933 flags |= SLAB_NO_MERGE;
934
935 if (minalign > ARCH_KMALLOC_MINALIGN) {
936 aligned_size = ALIGN(aligned_size, minalign);
937 aligned_idx = __kmalloc_index(aligned_size, false);
938 }
939
940 if (!kmalloc_caches[type][aligned_idx])
941 kmalloc_caches[type][aligned_idx] = create_kmalloc_cache(
942 kmalloc_info[aligned_idx].name[type],
943 aligned_size, flags);
944 if (idx != aligned_idx)
945 kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx];
946}
947
948/*
949 * Create the kmalloc array. Some of the regular kmalloc arrays
950 * may already have been created because they were needed to
951 * enable allocations for slab creation.
952 */
953void __init create_kmalloc_caches(void)
954{
955 int i;
956 enum kmalloc_cache_type type;
957
958 /*
959 * Including KMALLOC_CGROUP if CONFIG_MEMCG defined
960 */
961 for (type = KMALLOC_NORMAL; type < NR_KMALLOC_TYPES; type++) {
962 /* Caches that are NOT of the two-to-the-power-of size. */
963 if (KMALLOC_MIN_SIZE <= 32)
964 new_kmalloc_cache(1, type);
965 if (KMALLOC_MIN_SIZE <= 64)
966 new_kmalloc_cache(2, type);
967
968 /* Caches that are of the two-to-the-power-of size. */
969 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
970 new_kmalloc_cache(i, type);
971 }
972#ifdef CONFIG_RANDOM_KMALLOC_CACHES
973 random_kmalloc_seed = get_random_u64();
974#endif
975
976 /* Kmalloc array is now usable */
977 slab_state = UP;
978
979 if (IS_ENABLED(CONFIG_SLAB_BUCKETS))
980 kmem_buckets_cache = kmem_cache_create("kmalloc_buckets",
981 sizeof(kmem_buckets),
982 0, SLAB_NO_MERGE, NULL);
983}
984
985/**
986 * __ksize -- Report full size of underlying allocation
987 * @object: pointer to the object
988 *
989 * This should only be used internally to query the true size of allocations.
990 * It is not meant to be a way to discover the usable size of an allocation
991 * after the fact. Instead, use kmalloc_size_roundup(). Using memory beyond
992 * the originally requested allocation size may trigger KASAN, UBSAN_BOUNDS,
993 * and/or FORTIFY_SOURCE.
994 *
995 * Return: size of the actual memory used by @object in bytes
996 */
997size_t __ksize(const void *object)
998{
999 struct folio *folio;
1000
1001 if (unlikely(object == ZERO_SIZE_PTR))
1002 return 0;
1003
1004 folio = virt_to_folio(object);
1005
1006 if (unlikely(!folio_test_slab(folio))) {
1007 if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE))
1008 return 0;
1009 if (WARN_ON(object != folio_address(folio)))
1010 return 0;
1011 return folio_size(folio);
1012 }
1013
1014#ifdef CONFIG_SLUB_DEBUG
1015 skip_orig_size_check(folio_slab(folio)->slab_cache, object);
1016#endif
1017
1018 return slab_ksize(folio_slab(folio)->slab_cache);
1019}
1020
1021gfp_t kmalloc_fix_flags(gfp_t flags)
1022{
1023 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1024
1025 flags &= ~GFP_SLAB_BUG_MASK;
1026 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1027 invalid_mask, &invalid_mask, flags, &flags);
1028 dump_stack();
1029
1030 return flags;
1031}
1032
1033#ifdef CONFIG_SLAB_FREELIST_RANDOM
1034/* Randomize a generic freelist */
1035static void freelist_randomize(unsigned int *list,
1036 unsigned int count)
1037{
1038 unsigned int rand;
1039 unsigned int i;
1040
1041 for (i = 0; i < count; i++)
1042 list[i] = i;
1043
1044 /* Fisher-Yates shuffle */
1045 for (i = count - 1; i > 0; i--) {
1046 rand = get_random_u32_below(i + 1);
1047 swap(list[i], list[rand]);
1048 }
1049}
1050
1051/* Create a random sequence per cache */
1052int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
1053 gfp_t gfp)
1054{
1055
1056 if (count < 2 || cachep->random_seq)
1057 return 0;
1058
1059 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
1060 if (!cachep->random_seq)
1061 return -ENOMEM;
1062
1063 freelist_randomize(cachep->random_seq, count);
1064 return 0;
1065}
1066
1067/* Destroy the per-cache random freelist sequence */
1068void cache_random_seq_destroy(struct kmem_cache *cachep)
1069{
1070 kfree(cachep->random_seq);
1071 cachep->random_seq = NULL;
1072}
1073#endif /* CONFIG_SLAB_FREELIST_RANDOM */
1074
1075#ifdef CONFIG_SLUB_DEBUG
1076#define SLABINFO_RIGHTS (0400)
1077
1078static void print_slabinfo_header(struct seq_file *m)
1079{
1080 /*
1081 * Output format version, so at least we can change it
1082 * without _too_ many complaints.
1083 */
1084 seq_puts(m, "slabinfo - version: 2.1\n");
1085 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
1086 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
1087 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
1088 seq_putc(m, '\n');
1089}
1090
1091static void *slab_start(struct seq_file *m, loff_t *pos)
1092{
1093 mutex_lock(&slab_mutex);
1094 return seq_list_start(&slab_caches, *pos);
1095}
1096
1097static void *slab_next(struct seq_file *m, void *p, loff_t *pos)
1098{
1099 return seq_list_next(p, &slab_caches, pos);
1100}
1101
1102static void slab_stop(struct seq_file *m, void *p)
1103{
1104 mutex_unlock(&slab_mutex);
1105}
1106
1107static void cache_show(struct kmem_cache *s, struct seq_file *m)
1108{
1109 struct slabinfo sinfo;
1110
1111 memset(&sinfo, 0, sizeof(sinfo));
1112 get_slabinfo(s, &sinfo);
1113
1114 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
1115 s->name, sinfo.active_objs, sinfo.num_objs, s->size,
1116 sinfo.objects_per_slab, (1 << sinfo.cache_order));
1117
1118 seq_printf(m, " : tunables %4u %4u %4u",
1119 sinfo.limit, sinfo.batchcount, sinfo.shared);
1120 seq_printf(m, " : slabdata %6lu %6lu %6lu",
1121 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
1122 seq_putc(m, '\n');
1123}
1124
1125static int slab_show(struct seq_file *m, void *p)
1126{
1127 struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
1128
1129 if (p == slab_caches.next)
1130 print_slabinfo_header(m);
1131 cache_show(s, m);
1132 return 0;
1133}
1134
1135void dump_unreclaimable_slab(void)
1136{
1137 struct kmem_cache *s;
1138 struct slabinfo sinfo;
1139
1140 /*
1141 * Here acquiring slab_mutex is risky since we don't prefer to get
1142 * sleep in oom path. But, without mutex hold, it may introduce a
1143 * risk of crash.
1144 * Use mutex_trylock to protect the list traverse, dump nothing
1145 * without acquiring the mutex.
1146 */
1147 if (!mutex_trylock(&slab_mutex)) {
1148 pr_warn("excessive unreclaimable slab but cannot dump stats\n");
1149 return;
1150 }
1151
1152 pr_info("Unreclaimable slab info:\n");
1153 pr_info("Name Used Total\n");
1154
1155 list_for_each_entry(s, &slab_caches, list) {
1156 if (s->flags & SLAB_RECLAIM_ACCOUNT)
1157 continue;
1158
1159 get_slabinfo(s, &sinfo);
1160
1161 if (sinfo.num_objs > 0)
1162 pr_info("%-17s %10luKB %10luKB\n", s->name,
1163 (sinfo.active_objs * s->size) / 1024,
1164 (sinfo.num_objs * s->size) / 1024);
1165 }
1166 mutex_unlock(&slab_mutex);
1167}
1168
1169/*
1170 * slabinfo_op - iterator that generates /proc/slabinfo
1171 *
1172 * Output layout:
1173 * cache-name
1174 * num-active-objs
1175 * total-objs
1176 * object size
1177 * num-active-slabs
1178 * total-slabs
1179 * num-pages-per-slab
1180 * + further values on SMP and with statistics enabled
1181 */
1182static const struct seq_operations slabinfo_op = {
1183 .start = slab_start,
1184 .next = slab_next,
1185 .stop = slab_stop,
1186 .show = slab_show,
1187};
1188
1189static int slabinfo_open(struct inode *inode, struct file *file)
1190{
1191 return seq_open(file, &slabinfo_op);
1192}
1193
1194static const struct proc_ops slabinfo_proc_ops = {
1195 .proc_flags = PROC_ENTRY_PERMANENT,
1196 .proc_open = slabinfo_open,
1197 .proc_read = seq_read,
1198 .proc_lseek = seq_lseek,
1199 .proc_release = seq_release,
1200};
1201
1202static int __init slab_proc_init(void)
1203{
1204 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
1205 return 0;
1206}
1207module_init(slab_proc_init);
1208
1209#endif /* CONFIG_SLUB_DEBUG */
1210
1211/**
1212 * kfree_sensitive - Clear sensitive information in memory before freeing
1213 * @p: object to free memory of
1214 *
1215 * The memory of the object @p points to is zeroed before freed.
1216 * If @p is %NULL, kfree_sensitive() does nothing.
1217 *
1218 * Note: this function zeroes the whole allocated buffer which can be a good
1219 * deal bigger than the requested buffer size passed to kmalloc(). So be
1220 * careful when using this function in performance sensitive code.
1221 */
1222void kfree_sensitive(const void *p)
1223{
1224 size_t ks;
1225 void *mem = (void *)p;
1226
1227 ks = ksize(mem);
1228 if (ks) {
1229 kasan_unpoison_range(mem, ks);
1230 memzero_explicit(mem, ks);
1231 }
1232 kfree(mem);
1233}
1234EXPORT_SYMBOL(kfree_sensitive);
1235
1236size_t ksize(const void *objp)
1237{
1238 /*
1239 * We need to first check that the pointer to the object is valid.
1240 * The KASAN report printed from ksize() is more useful, then when
1241 * it's printed later when the behaviour could be undefined due to
1242 * a potential use-after-free or double-free.
1243 *
1244 * We use kasan_check_byte(), which is supported for the hardware
1245 * tag-based KASAN mode, unlike kasan_check_read/write().
1246 *
1247 * If the pointed to memory is invalid, we return 0 to avoid users of
1248 * ksize() writing to and potentially corrupting the memory region.
1249 *
1250 * We want to perform the check before __ksize(), to avoid potentially
1251 * crashing in __ksize() due to accessing invalid metadata.
1252 */
1253 if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp))
1254 return 0;
1255
1256 return kfence_ksize(objp) ?: __ksize(objp);
1257}
1258EXPORT_SYMBOL(ksize);
1259
1260#ifdef CONFIG_BPF_SYSCALL
1261#include <linux/btf.h>
1262
1263__bpf_kfunc_start_defs();
1264
1265__bpf_kfunc struct kmem_cache *bpf_get_kmem_cache(u64 addr)
1266{
1267 struct slab *slab;
1268
1269 if (!virt_addr_valid((void *)(long)addr))
1270 return NULL;
1271
1272 slab = virt_to_slab((void *)(long)addr);
1273 return slab ? slab->slab_cache : NULL;
1274}
1275
1276__bpf_kfunc_end_defs();
1277#endif /* CONFIG_BPF_SYSCALL */
1278
1279/* Tracepoints definitions. */
1280EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1281EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1282EXPORT_TRACEPOINT_SYMBOL(kfree);
1283EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1284