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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/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