Line data Source code
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/proc_fs.h>
21 : #include <linux/debugfs.h>
22 : #include <linux/kasan.h>
23 : #include <asm/cacheflush.h>
24 : #include <asm/tlbflush.h>
25 : #include <asm/page.h>
26 : #include <linux/memcontrol.h>
27 : #include <linux/stackdepot.h>
28 :
29 : #include "internal.h"
30 : #include "slab.h"
31 :
32 : #define CREATE_TRACE_POINTS
33 : #include <trace/events/kmem.h>
34 :
35 : enum slab_state slab_state;
36 : LIST_HEAD(slab_caches);
37 : DEFINE_MUTEX(slab_mutex);
38 : struct kmem_cache *kmem_cache;
39 :
40 : static LIST_HEAD(slab_caches_to_rcu_destroy);
41 : static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
42 : static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
43 : slab_caches_to_rcu_destroy_workfn);
44 :
45 : /*
46 : * Set of flags that will prevent slab merging
47 : */
48 : #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
49 : SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
50 : SLAB_FAILSLAB | kasan_never_merge())
51 :
52 : #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
53 : SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
54 :
55 : /*
56 : * Merge control. If this is set then no merging of slab caches will occur.
57 : */
58 : static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
59 :
60 0 : static int __init setup_slab_nomerge(char *str)
61 : {
62 0 : slab_nomerge = true;
63 0 : return 1;
64 : }
65 :
66 0 : static int __init setup_slab_merge(char *str)
67 : {
68 0 : slab_nomerge = false;
69 0 : return 1;
70 : }
71 :
72 : #ifdef CONFIG_SLUB
73 : __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
74 : __setup_param("slub_merge", slub_merge, setup_slab_merge, 0);
75 : #endif
76 :
77 : __setup("slab_nomerge", setup_slab_nomerge);
78 : __setup("slab_merge", setup_slab_merge);
79 :
80 : /*
81 : * Determine the size of a slab object
82 : */
83 0 : unsigned int kmem_cache_size(struct kmem_cache *s)
84 : {
85 0 : return s->object_size;
86 : }
87 : EXPORT_SYMBOL(kmem_cache_size);
88 :
89 : #ifdef CONFIG_DEBUG_VM
90 : static int kmem_cache_sanity_check(const char *name, unsigned int size)
91 : {
92 : if (!name || in_interrupt() || size > KMALLOC_MAX_SIZE) {
93 : pr_err("kmem_cache_create(%s) integrity check failed\n", name);
94 : return -EINVAL;
95 : }
96 :
97 : WARN_ON(strchr(name, ' ')); /* It confuses parsers */
98 : return 0;
99 : }
100 : #else
101 : static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
102 : {
103 : return 0;
104 : }
105 : #endif
106 :
107 : /*
108 : * Figure out what the alignment of the objects will be given a set of
109 : * flags, a user specified alignment and the size of the objects.
110 : */
111 : static unsigned int calculate_alignment(slab_flags_t flags,
112 : unsigned int align, unsigned int size)
113 : {
114 : /*
115 : * If the user wants hardware cache aligned objects then follow that
116 : * suggestion if the object is sufficiently large.
117 : *
118 : * The hardware cache alignment cannot override the specified
119 : * alignment though. If that is greater then use it.
120 : */
121 102 : if (flags & SLAB_HWCACHE_ALIGN) {
122 : unsigned int ralign;
123 :
124 29 : ralign = cache_line_size();
125 29 : while (size <= ralign / 2)
126 : ralign /= 2;
127 29 : align = max(align, ralign);
128 : }
129 :
130 102 : align = max(align, arch_slab_minalign());
131 :
132 102 : return ALIGN(align, sizeof(void *));
133 : }
134 :
135 : /*
136 : * Find a mergeable slab cache
137 : */
138 52 : int slab_unmergeable(struct kmem_cache *s)
139 : {
140 1119 : if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
141 : return 1;
142 :
143 1082 : if (s->ctor)
144 : return 1;
145 :
146 : #ifdef CONFIG_HARDENED_USERCOPY
147 : if (s->usersize)
148 : return 1;
149 : #endif
150 :
151 : /*
152 : * We may have set a slab to be unmergeable during bootstrap.
153 : */
154 1025 : if (s->refcount < 0)
155 : return 1;
156 :
157 41 : return 0;
158 : }
159 :
160 57 : struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
161 : slab_flags_t flags, const char *name, void (*ctor)(void *))
162 : {
163 : struct kmem_cache *s;
164 :
165 57 : if (slab_nomerge)
166 : return NULL;
167 :
168 57 : if (ctor)
169 : return NULL;
170 :
171 50 : size = ALIGN(size, sizeof(void *));
172 50 : align = calculate_alignment(flags, align, size);
173 50 : size = ALIGN(size, align);
174 50 : flags = kmem_cache_flags(size, flags, name);
175 :
176 50 : if (flags & SLAB_NEVER_MERGE)
177 : return NULL;
178 :
179 1082 : list_for_each_entry_reverse(s, &slab_caches, list) {
180 1067 : if (slab_unmergeable(s))
181 181 : continue;
182 :
183 886 : if (size > s->size)
184 457 : continue;
185 :
186 429 : if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
187 171 : continue;
188 : /*
189 : * Check if alignment is compatible.
190 : * Courtesy of Adrian Drzewiecki
191 : */
192 258 : if ((s->size & ~(align - 1)) != s->size)
193 2 : continue;
194 :
195 256 : if (s->size - size >= sizeof(void *))
196 223 : continue;
197 :
198 : if (IS_ENABLED(CONFIG_SLAB) && align &&
199 : (align > s->align || s->align % align))
200 : continue;
201 :
202 : return s;
203 : }
204 : return NULL;
205 : }
206 :
207 24 : static struct kmem_cache *create_cache(const char *name,
208 : unsigned int object_size, unsigned int align,
209 : slab_flags_t flags, unsigned int useroffset,
210 : unsigned int usersize, void (*ctor)(void *),
211 : struct kmem_cache *root_cache)
212 : {
213 : struct kmem_cache *s;
214 : int err;
215 :
216 24 : if (WARN_ON(useroffset + usersize > object_size))
217 : useroffset = usersize = 0;
218 :
219 24 : err = -ENOMEM;
220 48 : s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
221 24 : if (!s)
222 : goto out;
223 :
224 24 : s->name = name;
225 24 : s->size = s->object_size = object_size;
226 24 : s->align = align;
227 24 : s->ctor = ctor;
228 : #ifdef CONFIG_HARDENED_USERCOPY
229 : s->useroffset = useroffset;
230 : s->usersize = usersize;
231 : #endif
232 :
233 24 : err = __kmem_cache_create(s, flags);
234 24 : if (err)
235 : goto out_free_cache;
236 :
237 24 : s->refcount = 1;
238 24 : list_add(&s->list, &slab_caches);
239 : out:
240 24 : if (err)
241 0 : return ERR_PTR(err);
242 : return s;
243 :
244 : out_free_cache:
245 0 : kmem_cache_free(kmem_cache, s);
246 : goto out;
247 : }
248 :
249 : /**
250 : * kmem_cache_create_usercopy - Create a cache with a region suitable
251 : * for copying to userspace
252 : * @name: A string which is used in /proc/slabinfo to identify this cache.
253 : * @size: The size of objects to be created in this cache.
254 : * @align: The required alignment for the objects.
255 : * @flags: SLAB flags
256 : * @useroffset: Usercopy region offset
257 : * @usersize: Usercopy region size
258 : * @ctor: A constructor for the objects.
259 : *
260 : * Cannot be called within a interrupt, but can be interrupted.
261 : * The @ctor is run when new pages are allocated by the cache.
262 : *
263 : * The flags are
264 : *
265 : * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
266 : * to catch references to uninitialised memory.
267 : *
268 : * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
269 : * for buffer overruns.
270 : *
271 : * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
272 : * cacheline. This can be beneficial if you're counting cycles as closely
273 : * as davem.
274 : *
275 : * Return: a pointer to the cache on success, NULL on failure.
276 : */
277 : struct kmem_cache *
278 57 : kmem_cache_create_usercopy(const char *name,
279 : unsigned int size, unsigned int align,
280 : slab_flags_t flags,
281 : unsigned int useroffset, unsigned int usersize,
282 : void (*ctor)(void *))
283 : {
284 57 : struct kmem_cache *s = NULL;
285 : const char *cache_name;
286 : int err;
287 :
288 : #ifdef CONFIG_SLUB_DEBUG
289 : /*
290 : * If no slub_debug was enabled globally, the static key is not yet
291 : * enabled by setup_slub_debug(). Enable it if the cache is being
292 : * created with any of the debugging flags passed explicitly.
293 : * It's also possible that this is the first cache created with
294 : * SLAB_STORE_USER and we should init stack_depot for it.
295 : */
296 57 : if (flags & SLAB_DEBUG_FLAGS)
297 0 : static_branch_enable(&slub_debug_enabled);
298 57 : if (flags & SLAB_STORE_USER)
299 0 : stack_depot_init();
300 : #endif
301 :
302 57 : mutex_lock(&slab_mutex);
303 :
304 57 : err = kmem_cache_sanity_check(name, size);
305 : if (err) {
306 : goto out_unlock;
307 : }
308 :
309 : /* Refuse requests with allocator specific flags */
310 57 : if (flags & ~SLAB_FLAGS_PERMITTED) {
311 : err = -EINVAL;
312 : goto out_unlock;
313 : }
314 :
315 : /*
316 : * Some allocators will constraint the set of valid flags to a subset
317 : * of all flags. We expect them to define CACHE_CREATE_MASK in this
318 : * case, and we'll just provide them with a sanitized version of the
319 : * passed flags.
320 : */
321 57 : flags &= CACHE_CREATE_MASK;
322 :
323 : /* Fail closed on bad usersize of useroffset values. */
324 : if (!IS_ENABLED(CONFIG_HARDENED_USERCOPY) ||
325 : WARN_ON(!usersize && useroffset) ||
326 : WARN_ON(size < usersize || size - usersize < useroffset))
327 57 : usersize = useroffset = 0;
328 :
329 : if (!usersize)
330 57 : s = __kmem_cache_alias(name, size, align, flags, ctor);
331 57 : if (s)
332 : goto out_unlock;
333 :
334 24 : cache_name = kstrdup_const(name, GFP_KERNEL);
335 24 : if (!cache_name) {
336 : err = -ENOMEM;
337 : goto out_unlock;
338 : }
339 :
340 24 : s = create_cache(cache_name, size,
341 : calculate_alignment(flags, align, size),
342 : flags, useroffset, usersize, ctor, NULL);
343 24 : if (IS_ERR(s)) {
344 0 : err = PTR_ERR(s);
345 0 : kfree_const(cache_name);
346 : }
347 :
348 : out_unlock:
349 57 : mutex_unlock(&slab_mutex);
350 :
351 57 : if (err) {
352 0 : if (flags & SLAB_PANIC)
353 0 : panic("%s: Failed to create slab '%s'. Error %d\n",
354 : __func__, name, err);
355 : else {
356 0 : pr_warn("%s(%s) failed with error %d\n",
357 : __func__, name, err);
358 0 : dump_stack();
359 : }
360 0 : return NULL;
361 : }
362 : return s;
363 : }
364 : EXPORT_SYMBOL(kmem_cache_create_usercopy);
365 :
366 : /**
367 : * kmem_cache_create - Create a cache.
368 : * @name: A string which is used in /proc/slabinfo to identify this cache.
369 : * @size: The size of objects to be created in this cache.
370 : * @align: The required alignment for the objects.
371 : * @flags: SLAB flags
372 : * @ctor: A constructor for the objects.
373 : *
374 : * Cannot be called within a interrupt, but can be interrupted.
375 : * The @ctor is run when new pages are allocated by the cache.
376 : *
377 : * The flags are
378 : *
379 : * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
380 : * to catch references to uninitialised memory.
381 : *
382 : * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
383 : * for buffer overruns.
384 : *
385 : * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
386 : * cacheline. This can be beneficial if you're counting cycles as closely
387 : * as davem.
388 : *
389 : * Return: a pointer to the cache on success, NULL on failure.
390 : */
391 : struct kmem_cache *
392 51 : kmem_cache_create(const char *name, unsigned int size, unsigned int align,
393 : slab_flags_t flags, void (*ctor)(void *))
394 : {
395 51 : return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
396 : ctor);
397 : }
398 : EXPORT_SYMBOL(kmem_cache_create);
399 :
400 : #ifdef SLAB_SUPPORTS_SYSFS
401 : /*
402 : * For a given kmem_cache, kmem_cache_destroy() should only be called
403 : * once or there will be a use-after-free problem. The actual deletion
404 : * and release of the kobject does not need slab_mutex or cpu_hotplug_lock
405 : * protection. So they are now done without holding those locks.
406 : *
407 : * Note that there will be a slight delay in the deletion of sysfs files
408 : * if kmem_cache_release() is called indrectly from a work function.
409 : */
410 : static void kmem_cache_release(struct kmem_cache *s)
411 : {
412 0 : sysfs_slab_unlink(s);
413 0 : sysfs_slab_release(s);
414 : }
415 : #else
416 : static void kmem_cache_release(struct kmem_cache *s)
417 : {
418 : slab_kmem_cache_release(s);
419 : }
420 : #endif
421 :
422 0 : static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
423 : {
424 0 : LIST_HEAD(to_destroy);
425 : struct kmem_cache *s, *s2;
426 :
427 : /*
428 : * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
429 : * @slab_caches_to_rcu_destroy list. The slab pages are freed
430 : * through RCU and the associated kmem_cache are dereferenced
431 : * while freeing the pages, so the kmem_caches should be freed only
432 : * after the pending RCU operations are finished. As rcu_barrier()
433 : * is a pretty slow operation, we batch all pending destructions
434 : * asynchronously.
435 : */
436 0 : mutex_lock(&slab_mutex);
437 0 : list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
438 0 : mutex_unlock(&slab_mutex);
439 :
440 0 : if (list_empty(&to_destroy))
441 0 : return;
442 :
443 0 : rcu_barrier();
444 :
445 0 : list_for_each_entry_safe(s, s2, &to_destroy, list) {
446 0 : debugfs_slab_release(s);
447 0 : kfence_shutdown_cache(s);
448 0 : kmem_cache_release(s);
449 : }
450 : }
451 :
452 0 : static int shutdown_cache(struct kmem_cache *s)
453 : {
454 : /* free asan quarantined objects */
455 0 : kasan_cache_shutdown(s);
456 :
457 0 : if (__kmem_cache_shutdown(s) != 0)
458 : return -EBUSY;
459 :
460 0 : list_del(&s->list);
461 :
462 0 : if (s->flags & SLAB_TYPESAFE_BY_RCU) {
463 0 : list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
464 : schedule_work(&slab_caches_to_rcu_destroy_work);
465 : } else {
466 : kfence_shutdown_cache(s);
467 : debugfs_slab_release(s);
468 : }
469 :
470 : return 0;
471 : }
472 :
473 0 : void slab_kmem_cache_release(struct kmem_cache *s)
474 : {
475 0 : __kmem_cache_release(s);
476 0 : kfree_const(s->name);
477 0 : kmem_cache_free(kmem_cache, s);
478 0 : }
479 :
480 0 : void kmem_cache_destroy(struct kmem_cache *s)
481 : {
482 : int refcnt;
483 : bool rcu_set;
484 :
485 0 : if (unlikely(!s) || !kasan_check_byte(s))
486 : return;
487 :
488 : cpus_read_lock();
489 0 : mutex_lock(&slab_mutex);
490 :
491 0 : rcu_set = s->flags & SLAB_TYPESAFE_BY_RCU;
492 :
493 0 : refcnt = --s->refcount;
494 0 : if (refcnt)
495 : goto out_unlock;
496 :
497 0 : WARN(shutdown_cache(s),
498 : "%s %s: Slab cache still has objects when called from %pS",
499 : __func__, s->name, (void *)_RET_IP_);
500 : out_unlock:
501 0 : mutex_unlock(&slab_mutex);
502 : cpus_read_unlock();
503 0 : if (!refcnt && !rcu_set)
504 : kmem_cache_release(s);
505 : }
506 : EXPORT_SYMBOL(kmem_cache_destroy);
507 :
508 : /**
509 : * kmem_cache_shrink - Shrink a cache.
510 : * @cachep: The cache to shrink.
511 : *
512 : * Releases as many slabs as possible for a cache.
513 : * To help debugging, a zero exit status indicates all slabs were released.
514 : *
515 : * Return: %0 if all slabs were released, non-zero otherwise
516 : */
517 0 : int kmem_cache_shrink(struct kmem_cache *cachep)
518 : {
519 0 : kasan_cache_shrink(cachep);
520 :
521 0 : return __kmem_cache_shrink(cachep);
522 : }
523 : EXPORT_SYMBOL(kmem_cache_shrink);
524 :
525 22 : bool slab_is_available(void)
526 : {
527 22 : return slab_state >= UP;
528 : }
529 :
530 : #ifdef CONFIG_PRINTK
531 : /**
532 : * kmem_valid_obj - does the pointer reference a valid slab object?
533 : * @object: pointer to query.
534 : *
535 : * Return: %true if the pointer is to a not-yet-freed object from
536 : * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer
537 : * is to an already-freed object, and %false otherwise.
538 : */
539 0 : bool kmem_valid_obj(void *object)
540 : {
541 : struct folio *folio;
542 :
543 : /* Some arches consider ZERO_SIZE_PTR to be a valid address. */
544 0 : if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
545 : return false;
546 0 : folio = virt_to_folio(object);
547 0 : return folio_test_slab(folio);
548 : }
549 : EXPORT_SYMBOL_GPL(kmem_valid_obj);
550 :
551 : static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
552 : {
553 0 : if (__kfence_obj_info(kpp, object, slab))
554 : return;
555 0 : __kmem_obj_info(kpp, object, slab);
556 : }
557 :
558 : /**
559 : * kmem_dump_obj - Print available slab provenance information
560 : * @object: slab object for which to find provenance information.
561 : *
562 : * This function uses pr_cont(), so that the caller is expected to have
563 : * printed out whatever preamble is appropriate. The provenance information
564 : * depends on the type of object and on how much debugging is enabled.
565 : * For a slab-cache object, the fact that it is a slab object is printed,
566 : * and, if available, the slab name, return address, and stack trace from
567 : * the allocation and last free path of that object.
568 : *
569 : * This function will splat if passed a pointer to a non-slab object.
570 : * If you are not sure what type of object you have, you should instead
571 : * use mem_dump_obj().
572 : */
573 0 : void kmem_dump_obj(void *object)
574 : {
575 0 : char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
576 : int i;
577 : struct slab *slab;
578 : unsigned long ptroffset;
579 0 : struct kmem_obj_info kp = { };
580 :
581 0 : if (WARN_ON_ONCE(!virt_addr_valid(object)))
582 0 : return;
583 0 : slab = virt_to_slab(object);
584 0 : if (WARN_ON_ONCE(!slab)) {
585 0 : pr_cont(" non-slab memory.\n");
586 0 : return;
587 : }
588 0 : kmem_obj_info(&kp, object, slab);
589 0 : if (kp.kp_slab_cache)
590 0 : pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name);
591 : else
592 0 : pr_cont(" slab%s", cp);
593 0 : if (is_kfence_address(object))
594 : pr_cont(" (kfence)");
595 0 : if (kp.kp_objp)
596 0 : pr_cont(" start %px", kp.kp_objp);
597 0 : if (kp.kp_data_offset)
598 0 : pr_cont(" data offset %lu", kp.kp_data_offset);
599 0 : if (kp.kp_objp) {
600 0 : ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset;
601 0 : pr_cont(" pointer offset %lu", ptroffset);
602 : }
603 0 : if (kp.kp_slab_cache && kp.kp_slab_cache->object_size)
604 0 : pr_cont(" size %u", kp.kp_slab_cache->object_size);
605 0 : if (kp.kp_ret)
606 0 : pr_cont(" allocated at %pS\n", kp.kp_ret);
607 : else
608 0 : pr_cont("\n");
609 0 : for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) {
610 0 : if (!kp.kp_stack[i])
611 : break;
612 0 : pr_info(" %pS\n", kp.kp_stack[i]);
613 : }
614 :
615 0 : if (kp.kp_free_stack[0])
616 0 : pr_cont(" Free path:\n");
617 :
618 0 : for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) {
619 0 : if (!kp.kp_free_stack[i])
620 : break;
621 0 : pr_info(" %pS\n", kp.kp_free_stack[i]);
622 : }
623 :
624 : }
625 : EXPORT_SYMBOL_GPL(kmem_dump_obj);
626 : #endif
627 :
628 : #ifndef CONFIG_SLOB
629 : /* Create a cache during boot when no slab services are available yet */
630 28 : void __init create_boot_cache(struct kmem_cache *s, const char *name,
631 : unsigned int size, slab_flags_t flags,
632 : unsigned int useroffset, unsigned int usersize)
633 : {
634 : int err;
635 28 : unsigned int align = ARCH_KMALLOC_MINALIGN;
636 :
637 28 : s->name = name;
638 28 : s->size = s->object_size = size;
639 :
640 : /*
641 : * For power of two sizes, guarantee natural alignment for kmalloc
642 : * caches, regardless of SL*B debugging options.
643 : */
644 56 : if (is_power_of_2(size))
645 22 : align = max(align, size);
646 28 : s->align = calculate_alignment(flags, align, size);
647 :
648 : #ifdef CONFIG_HARDENED_USERCOPY
649 : s->useroffset = useroffset;
650 : s->usersize = usersize;
651 : #endif
652 :
653 28 : err = __kmem_cache_create(s, flags);
654 :
655 28 : if (err)
656 0 : panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
657 : name, size, err);
658 :
659 28 : s->refcount = -1; /* Exempt from merging for now */
660 28 : }
661 :
662 26 : struct kmem_cache *__init create_kmalloc_cache(const char *name,
663 : unsigned int size, slab_flags_t flags,
664 : unsigned int useroffset, unsigned int usersize)
665 : {
666 52 : struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
667 :
668 26 : if (!s)
669 0 : panic("Out of memory when creating slab %s\n", name);
670 :
671 26 : create_boot_cache(s, name, size, flags | SLAB_KMALLOC, useroffset,
672 : usersize);
673 52 : list_add(&s->list, &slab_caches);
674 26 : s->refcount = 1;
675 26 : return s;
676 : }
677 :
678 : struct kmem_cache *
679 : kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
680 : { /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
681 : EXPORT_SYMBOL(kmalloc_caches);
682 :
683 : /*
684 : * Conversion table for small slabs sizes / 8 to the index in the
685 : * kmalloc array. This is necessary for slabs < 192 since we have non power
686 : * of two cache sizes there. The size of larger slabs can be determined using
687 : * fls.
688 : */
689 : static u8 size_index[24] __ro_after_init = {
690 : 3, /* 8 */
691 : 4, /* 16 */
692 : 5, /* 24 */
693 : 5, /* 32 */
694 : 6, /* 40 */
695 : 6, /* 48 */
696 : 6, /* 56 */
697 : 6, /* 64 */
698 : 1, /* 72 */
699 : 1, /* 80 */
700 : 1, /* 88 */
701 : 1, /* 96 */
702 : 7, /* 104 */
703 : 7, /* 112 */
704 : 7, /* 120 */
705 : 7, /* 128 */
706 : 2, /* 136 */
707 : 2, /* 144 */
708 : 2, /* 152 */
709 : 2, /* 160 */
710 : 2, /* 168 */
711 : 2, /* 176 */
712 : 2, /* 184 */
713 : 2 /* 192 */
714 : };
715 :
716 : static inline unsigned int size_index_elem(unsigned int bytes)
717 : {
718 4321 : return (bytes - 1) / 8;
719 : }
720 :
721 : /*
722 : * Find the kmem_cache structure that serves a given size of
723 : * allocation
724 : */
725 5023 : struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
726 : {
727 : unsigned int index;
728 :
729 5023 : if (size <= 192) {
730 4325 : if (!size)
731 : return ZERO_SIZE_PTR;
732 :
733 8642 : index = size_index[size_index_elem(size)];
734 : } else {
735 698 : if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
736 : return NULL;
737 1396 : index = fls(size - 1);
738 : }
739 :
740 5019 : return kmalloc_caches[kmalloc_type(flags)][index];
741 : }
742 :
743 17 : size_t kmalloc_size_roundup(size_t size)
744 : {
745 : struct kmem_cache *c;
746 :
747 : /* Short-circuit the 0 size case. */
748 17 : if (unlikely(size == 0))
749 : return 0;
750 : /* Short-circuit saturated "too-large" case. */
751 17 : if (unlikely(size == SIZE_MAX))
752 : return SIZE_MAX;
753 : /* Above the smaller buckets, size is a multiple of page size. */
754 17 : if (size > KMALLOC_MAX_CACHE_SIZE)
755 0 : return PAGE_SIZE << get_order(size);
756 :
757 : /* The flags don't matter since size_index is common to all. */
758 17 : c = kmalloc_slab(size, GFP_KERNEL);
759 17 : return c ? c->object_size : 0;
760 : }
761 : EXPORT_SYMBOL(kmalloc_size_roundup);
762 :
763 : #ifdef CONFIG_ZONE_DMA
764 : #define KMALLOC_DMA_NAME(sz) .name[KMALLOC_DMA] = "dma-kmalloc-" #sz,
765 : #else
766 : #define KMALLOC_DMA_NAME(sz)
767 : #endif
768 :
769 : #ifdef CONFIG_MEMCG_KMEM
770 : #define KMALLOC_CGROUP_NAME(sz) .name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz,
771 : #else
772 : #define KMALLOC_CGROUP_NAME(sz)
773 : #endif
774 :
775 : #ifndef CONFIG_SLUB_TINY
776 : #define KMALLOC_RCL_NAME(sz) .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #sz,
777 : #else
778 : #define KMALLOC_RCL_NAME(sz)
779 : #endif
780 :
781 : #define INIT_KMALLOC_INFO(__size, __short_size) \
782 : { \
783 : .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
784 : KMALLOC_RCL_NAME(__short_size) \
785 : KMALLOC_CGROUP_NAME(__short_size) \
786 : KMALLOC_DMA_NAME(__short_size) \
787 : .size = __size, \
788 : }
789 :
790 : /*
791 : * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
792 : * kmalloc_index() supports up to 2^21=2MB, so the final entry of the table is
793 : * kmalloc-2M.
794 : */
795 : const struct kmalloc_info_struct kmalloc_info[] __initconst = {
796 : INIT_KMALLOC_INFO(0, 0),
797 : INIT_KMALLOC_INFO(96, 96),
798 : INIT_KMALLOC_INFO(192, 192),
799 : INIT_KMALLOC_INFO(8, 8),
800 : INIT_KMALLOC_INFO(16, 16),
801 : INIT_KMALLOC_INFO(32, 32),
802 : INIT_KMALLOC_INFO(64, 64),
803 : INIT_KMALLOC_INFO(128, 128),
804 : INIT_KMALLOC_INFO(256, 256),
805 : INIT_KMALLOC_INFO(512, 512),
806 : INIT_KMALLOC_INFO(1024, 1k),
807 : INIT_KMALLOC_INFO(2048, 2k),
808 : INIT_KMALLOC_INFO(4096, 4k),
809 : INIT_KMALLOC_INFO(8192, 8k),
810 : INIT_KMALLOC_INFO(16384, 16k),
811 : INIT_KMALLOC_INFO(32768, 32k),
812 : INIT_KMALLOC_INFO(65536, 64k),
813 : INIT_KMALLOC_INFO(131072, 128k),
814 : INIT_KMALLOC_INFO(262144, 256k),
815 : INIT_KMALLOC_INFO(524288, 512k),
816 : INIT_KMALLOC_INFO(1048576, 1M),
817 : INIT_KMALLOC_INFO(2097152, 2M)
818 : };
819 :
820 : /*
821 : * Patch up the size_index table if we have strange large alignment
822 : * requirements for the kmalloc array. This is only the case for
823 : * MIPS it seems. The standard arches will not generate any code here.
824 : *
825 : * Largest permitted alignment is 256 bytes due to the way we
826 : * handle the index determination for the smaller caches.
827 : *
828 : * Make sure that nothing crazy happens if someone starts tinkering
829 : * around with ARCH_KMALLOC_MINALIGN
830 : */
831 1 : void __init setup_kmalloc_cache_index_table(void)
832 : {
833 : unsigned int i;
834 :
835 1 : BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
836 : !is_power_of_2(KMALLOC_MIN_SIZE));
837 :
838 1 : for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
839 : unsigned int elem = size_index_elem(i);
840 :
841 : if (elem >= ARRAY_SIZE(size_index))
842 : break;
843 : size_index[elem] = KMALLOC_SHIFT_LOW;
844 : }
845 :
846 : if (KMALLOC_MIN_SIZE >= 64) {
847 : /*
848 : * The 96 byte sized cache is not used if the alignment
849 : * is 64 byte.
850 : */
851 : for (i = 64 + 8; i <= 96; i += 8)
852 : size_index[size_index_elem(i)] = 7;
853 :
854 : }
855 :
856 : if (KMALLOC_MIN_SIZE >= 128) {
857 : /*
858 : * The 192 byte sized cache is not used if the alignment
859 : * is 128 byte. Redirect kmalloc to use the 256 byte cache
860 : * instead.
861 : */
862 : for (i = 128 + 8; i <= 192; i += 8)
863 : size_index[size_index_elem(i)] = 8;
864 : }
865 1 : }
866 :
867 : static void __init
868 26 : new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
869 : {
870 26 : if ((KMALLOC_RECLAIM != KMALLOC_NORMAL) && (type == KMALLOC_RECLAIM)) {
871 13 : flags |= SLAB_RECLAIM_ACCOUNT;
872 : } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) {
873 : if (mem_cgroup_kmem_disabled()) {
874 : kmalloc_caches[type][idx] = kmalloc_caches[KMALLOC_NORMAL][idx];
875 : return;
876 : }
877 : flags |= SLAB_ACCOUNT;
878 : } else if (IS_ENABLED(CONFIG_ZONE_DMA) && (type == KMALLOC_DMA)) {
879 : flags |= SLAB_CACHE_DMA;
880 : }
881 :
882 26 : kmalloc_caches[type][idx] = create_kmalloc_cache(
883 : kmalloc_info[idx].name[type],
884 : kmalloc_info[idx].size, flags, 0,
885 : kmalloc_info[idx].size);
886 :
887 : /*
888 : * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for
889 : * KMALLOC_NORMAL caches.
890 : */
891 : if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_NORMAL))
892 : kmalloc_caches[type][idx]->refcount = -1;
893 : }
894 :
895 : /*
896 : * Create the kmalloc array. Some of the regular kmalloc arrays
897 : * may already have been created because they were needed to
898 : * enable allocations for slab creation.
899 : */
900 1 : void __init create_kmalloc_caches(slab_flags_t flags)
901 : {
902 : int i;
903 : enum kmalloc_cache_type type;
904 :
905 : /*
906 : * Including KMALLOC_CGROUP if CONFIG_MEMCG_KMEM defined
907 : */
908 3 : for (type = KMALLOC_NORMAL; type < NR_KMALLOC_TYPES; type++) {
909 22 : for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
910 22 : if (!kmalloc_caches[type][i])
911 22 : new_kmalloc_cache(i, type, flags);
912 :
913 : /*
914 : * Caches that are not of the two-to-the-power-of size.
915 : * These have to be created immediately after the
916 : * earlier power of two caches
917 : */
918 24 : if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
919 2 : !kmalloc_caches[type][1])
920 2 : new_kmalloc_cache(1, type, flags);
921 24 : if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
922 2 : !kmalloc_caches[type][2])
923 2 : new_kmalloc_cache(2, type, flags);
924 : }
925 : }
926 :
927 : /* Kmalloc array is now usable */
928 1 : slab_state = UP;
929 1 : }
930 :
931 6 : void free_large_kmalloc(struct folio *folio, void *object)
932 : {
933 6 : unsigned int order = folio_order(folio);
934 :
935 6 : if (WARN_ON_ONCE(order == 0))
936 0 : pr_warn_once("object pointer: 0x%p\n", object);
937 :
938 6 : kmemleak_free(object);
939 6 : kasan_kfree_large(object);
940 6 : kmsan_kfree_large(object);
941 :
942 12 : mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B,
943 6 : -(PAGE_SIZE << order));
944 6 : __free_pages(folio_page(folio, 0), order);
945 6 : }
946 :
947 : static void *__kmalloc_large_node(size_t size, gfp_t flags, int node);
948 : static __always_inline
949 : void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
950 : {
951 : struct kmem_cache *s;
952 : void *ret;
953 :
954 5012 : if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
955 6 : ret = __kmalloc_large_node(size, flags, node);
956 : trace_kmalloc(caller, ret, size,
957 : PAGE_SIZE << get_order(size), flags, node);
958 : return ret;
959 : }
960 :
961 5006 : s = kmalloc_slab(size, flags);
962 :
963 5006 : if (unlikely(ZERO_OR_NULL_PTR(s)))
964 : return s;
965 :
966 5002 : ret = __kmem_cache_alloc_node(s, flags, node, size, caller);
967 5002 : ret = kasan_kmalloc(s, ret, size, flags);
968 5002 : trace_kmalloc(caller, ret, size, s->size, flags, node);
969 : return ret;
970 : }
971 :
972 277 : void *__kmalloc_node(size_t size, gfp_t flags, int node)
973 : {
974 554 : return __do_kmalloc_node(size, flags, node, _RET_IP_);
975 : }
976 : EXPORT_SYMBOL(__kmalloc_node);
977 :
978 1820 : void *__kmalloc(size_t size, gfp_t flags)
979 : {
980 3640 : return __do_kmalloc_node(size, flags, NUMA_NO_NODE, _RET_IP_);
981 : }
982 : EXPORT_SYMBOL(__kmalloc);
983 :
984 2915 : void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
985 : int node, unsigned long caller)
986 : {
987 2915 : return __do_kmalloc_node(size, flags, node, caller);
988 : }
989 : EXPORT_SYMBOL(__kmalloc_node_track_caller);
990 :
991 : /**
992 : * kfree - free previously allocated memory
993 : * @object: pointer returned by kmalloc.
994 : *
995 : * If @object is NULL, no operation is performed.
996 : *
997 : * Don't free memory not originally allocated by kmalloc()
998 : * or you will run into trouble.
999 : */
1000 44604 : void kfree(const void *object)
1001 : {
1002 : struct folio *folio;
1003 : struct slab *slab;
1004 : struct kmem_cache *s;
1005 :
1006 44604 : trace_kfree(_RET_IP_, object);
1007 :
1008 44604 : if (unlikely(ZERO_OR_NULL_PTR(object)))
1009 : return;
1010 :
1011 42858 : folio = virt_to_folio(object);
1012 42858 : if (unlikely(!folio_test_slab(folio))) {
1013 6 : free_large_kmalloc(folio, (void *)object);
1014 6 : return;
1015 : }
1016 :
1017 42852 : slab = folio_slab(folio);
1018 42852 : s = slab->slab_cache;
1019 42852 : __kmem_cache_free(s, (void *)object, _RET_IP_);
1020 : }
1021 : EXPORT_SYMBOL(kfree);
1022 :
1023 : /**
1024 : * __ksize -- Report full size of underlying allocation
1025 : * @object: pointer to the object
1026 : *
1027 : * This should only be used internally to query the true size of allocations.
1028 : * It is not meant to be a way to discover the usable size of an allocation
1029 : * after the fact. Instead, use kmalloc_size_roundup(). Using memory beyond
1030 : * the originally requested allocation size may trigger KASAN, UBSAN_BOUNDS,
1031 : * and/or FORTIFY_SOURCE.
1032 : *
1033 : * Return: size of the actual memory used by @object in bytes
1034 : */
1035 113 : size_t __ksize(const void *object)
1036 : {
1037 : struct folio *folio;
1038 :
1039 113 : if (unlikely(object == ZERO_SIZE_PTR))
1040 : return 0;
1041 :
1042 113 : folio = virt_to_folio(object);
1043 :
1044 113 : if (unlikely(!folio_test_slab(folio))) {
1045 0 : if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE))
1046 : return 0;
1047 0 : if (WARN_ON(object != folio_address(folio)))
1048 : return 0;
1049 0 : return folio_size(folio);
1050 : }
1051 :
1052 : #ifdef CONFIG_SLUB_DEBUG
1053 113 : skip_orig_size_check(folio_slab(folio)->slab_cache, object);
1054 : #endif
1055 :
1056 113 : return slab_ksize(folio_slab(folio)->slab_cache);
1057 : }
1058 :
1059 41293 : void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
1060 : {
1061 41293 : void *ret = __kmem_cache_alloc_node(s, gfpflags, NUMA_NO_NODE,
1062 41293 : size, _RET_IP_);
1063 :
1064 41293 : trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE);
1065 :
1066 41293 : ret = kasan_kmalloc(s, ret, size, gfpflags);
1067 41293 : return ret;
1068 : }
1069 : EXPORT_SYMBOL(kmalloc_trace);
1070 :
1071 285 : void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
1072 : int node, size_t size)
1073 : {
1074 285 : void *ret = __kmem_cache_alloc_node(s, gfpflags, node, size, _RET_IP_);
1075 :
1076 285 : trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node);
1077 :
1078 285 : ret = kasan_kmalloc(s, ret, size, gfpflags);
1079 285 : return ret;
1080 : }
1081 : EXPORT_SYMBOL(kmalloc_node_trace);
1082 : #endif /* !CONFIG_SLOB */
1083 :
1084 0 : gfp_t kmalloc_fix_flags(gfp_t flags)
1085 : {
1086 0 : gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1087 :
1088 0 : flags &= ~GFP_SLAB_BUG_MASK;
1089 0 : pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1090 : invalid_mask, &invalid_mask, flags, &flags);
1091 0 : dump_stack();
1092 :
1093 0 : return flags;
1094 : }
1095 :
1096 : /*
1097 : * To avoid unnecessary overhead, we pass through large allocation requests
1098 : * directly to the page allocator. We use __GFP_COMP, because we will need to
1099 : * know the allocation order to free the pages properly in kfree.
1100 : */
1101 :
1102 6 : static void *__kmalloc_large_node(size_t size, gfp_t flags, int node)
1103 : {
1104 : struct page *page;
1105 6 : void *ptr = NULL;
1106 6 : unsigned int order = get_order(size);
1107 :
1108 6 : if (unlikely(flags & GFP_SLAB_BUG_MASK))
1109 0 : flags = kmalloc_fix_flags(flags);
1110 :
1111 6 : flags |= __GFP_COMP;
1112 6 : page = alloc_pages_node(node, flags, order);
1113 6 : if (page) {
1114 6 : ptr = page_address(page);
1115 6 : mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
1116 6 : PAGE_SIZE << order);
1117 : }
1118 :
1119 6 : ptr = kasan_kmalloc_large(ptr, size, flags);
1120 : /* As ptr might get tagged, call kmemleak hook after KASAN. */
1121 6 : kmemleak_alloc(ptr, size, 1, flags);
1122 6 : kmsan_kmalloc_large(ptr, size, flags);
1123 :
1124 6 : return ptr;
1125 : }
1126 :
1127 0 : void *kmalloc_large(size_t size, gfp_t flags)
1128 : {
1129 0 : void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE);
1130 :
1131 0 : trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
1132 : flags, NUMA_NO_NODE);
1133 0 : return ret;
1134 : }
1135 : EXPORT_SYMBOL(kmalloc_large);
1136 :
1137 0 : void *kmalloc_large_node(size_t size, gfp_t flags, int node)
1138 : {
1139 0 : void *ret = __kmalloc_large_node(size, flags, node);
1140 :
1141 0 : trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
1142 : flags, node);
1143 0 : return ret;
1144 : }
1145 : EXPORT_SYMBOL(kmalloc_large_node);
1146 :
1147 : #ifdef CONFIG_SLAB_FREELIST_RANDOM
1148 : /* Randomize a generic freelist */
1149 : static void freelist_randomize(struct rnd_state *state, unsigned int *list,
1150 : unsigned int count)
1151 : {
1152 : unsigned int rand;
1153 : unsigned int i;
1154 :
1155 : for (i = 0; i < count; i++)
1156 : list[i] = i;
1157 :
1158 : /* Fisher-Yates shuffle */
1159 : for (i = count - 1; i > 0; i--) {
1160 : rand = prandom_u32_state(state);
1161 : rand %= (i + 1);
1162 : swap(list[i], list[rand]);
1163 : }
1164 : }
1165 :
1166 : /* Create a random sequence per cache */
1167 : int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
1168 : gfp_t gfp)
1169 : {
1170 : struct rnd_state state;
1171 :
1172 : if (count < 2 || cachep->random_seq)
1173 : return 0;
1174 :
1175 : cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
1176 : if (!cachep->random_seq)
1177 : return -ENOMEM;
1178 :
1179 : /* Get best entropy at this stage of boot */
1180 : prandom_seed_state(&state, get_random_long());
1181 :
1182 : freelist_randomize(&state, cachep->random_seq, count);
1183 : return 0;
1184 : }
1185 :
1186 : /* Destroy the per-cache random freelist sequence */
1187 : void cache_random_seq_destroy(struct kmem_cache *cachep)
1188 : {
1189 : kfree(cachep->random_seq);
1190 : cachep->random_seq = NULL;
1191 : }
1192 : #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1193 :
1194 : #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
1195 : #ifdef CONFIG_SLAB
1196 : #define SLABINFO_RIGHTS (0600)
1197 : #else
1198 : #define SLABINFO_RIGHTS (0400)
1199 : #endif
1200 :
1201 0 : static void print_slabinfo_header(struct seq_file *m)
1202 : {
1203 : /*
1204 : * Output format version, so at least we can change it
1205 : * without _too_ many complaints.
1206 : */
1207 : #ifdef CONFIG_DEBUG_SLAB
1208 : seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
1209 : #else
1210 0 : seq_puts(m, "slabinfo - version: 2.1\n");
1211 : #endif
1212 0 : seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
1213 0 : seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
1214 0 : seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
1215 : #ifdef CONFIG_DEBUG_SLAB
1216 : seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
1217 : seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
1218 : #endif
1219 0 : seq_putc(m, '\n');
1220 0 : }
1221 :
1222 0 : static void *slab_start(struct seq_file *m, loff_t *pos)
1223 : {
1224 0 : mutex_lock(&slab_mutex);
1225 0 : return seq_list_start(&slab_caches, *pos);
1226 : }
1227 :
1228 0 : static void *slab_next(struct seq_file *m, void *p, loff_t *pos)
1229 : {
1230 0 : return seq_list_next(p, &slab_caches, pos);
1231 : }
1232 :
1233 0 : static void slab_stop(struct seq_file *m, void *p)
1234 : {
1235 0 : mutex_unlock(&slab_mutex);
1236 0 : }
1237 :
1238 0 : static void cache_show(struct kmem_cache *s, struct seq_file *m)
1239 : {
1240 : struct slabinfo sinfo;
1241 :
1242 0 : memset(&sinfo, 0, sizeof(sinfo));
1243 0 : get_slabinfo(s, &sinfo);
1244 :
1245 0 : seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
1246 : s->name, sinfo.active_objs, sinfo.num_objs, s->size,
1247 0 : sinfo.objects_per_slab, (1 << sinfo.cache_order));
1248 :
1249 0 : seq_printf(m, " : tunables %4u %4u %4u",
1250 : sinfo.limit, sinfo.batchcount, sinfo.shared);
1251 0 : seq_printf(m, " : slabdata %6lu %6lu %6lu",
1252 : sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
1253 0 : slabinfo_show_stats(m, s);
1254 0 : seq_putc(m, '\n');
1255 0 : }
1256 :
1257 0 : static int slab_show(struct seq_file *m, void *p)
1258 : {
1259 0 : struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
1260 :
1261 0 : if (p == slab_caches.next)
1262 0 : print_slabinfo_header(m);
1263 0 : cache_show(s, m);
1264 0 : return 0;
1265 : }
1266 :
1267 0 : void dump_unreclaimable_slab(void)
1268 : {
1269 : struct kmem_cache *s;
1270 : struct slabinfo sinfo;
1271 :
1272 : /*
1273 : * Here acquiring slab_mutex is risky since we don't prefer to get
1274 : * sleep in oom path. But, without mutex hold, it may introduce a
1275 : * risk of crash.
1276 : * Use mutex_trylock to protect the list traverse, dump nothing
1277 : * without acquiring the mutex.
1278 : */
1279 0 : if (!mutex_trylock(&slab_mutex)) {
1280 0 : pr_warn("excessive unreclaimable slab but cannot dump stats\n");
1281 0 : return;
1282 : }
1283 :
1284 0 : pr_info("Unreclaimable slab info:\n");
1285 0 : pr_info("Name Used Total\n");
1286 :
1287 0 : list_for_each_entry(s, &slab_caches, list) {
1288 0 : if (s->flags & SLAB_RECLAIM_ACCOUNT)
1289 0 : continue;
1290 :
1291 0 : get_slabinfo(s, &sinfo);
1292 :
1293 0 : if (sinfo.num_objs > 0)
1294 0 : pr_info("%-17s %10luKB %10luKB\n", s->name,
1295 : (sinfo.active_objs * s->size) / 1024,
1296 : (sinfo.num_objs * s->size) / 1024);
1297 : }
1298 0 : mutex_unlock(&slab_mutex);
1299 : }
1300 :
1301 : /*
1302 : * slabinfo_op - iterator that generates /proc/slabinfo
1303 : *
1304 : * Output layout:
1305 : * cache-name
1306 : * num-active-objs
1307 : * total-objs
1308 : * object size
1309 : * num-active-slabs
1310 : * total-slabs
1311 : * num-pages-per-slab
1312 : * + further values on SMP and with statistics enabled
1313 : */
1314 : static const struct seq_operations slabinfo_op = {
1315 : .start = slab_start,
1316 : .next = slab_next,
1317 : .stop = slab_stop,
1318 : .show = slab_show,
1319 : };
1320 :
1321 0 : static int slabinfo_open(struct inode *inode, struct file *file)
1322 : {
1323 0 : return seq_open(file, &slabinfo_op);
1324 : }
1325 :
1326 : static const struct proc_ops slabinfo_proc_ops = {
1327 : .proc_flags = PROC_ENTRY_PERMANENT,
1328 : .proc_open = slabinfo_open,
1329 : .proc_read = seq_read,
1330 : .proc_write = slabinfo_write,
1331 : .proc_lseek = seq_lseek,
1332 : .proc_release = seq_release,
1333 : };
1334 :
1335 1 : static int __init slab_proc_init(void)
1336 : {
1337 1 : proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
1338 1 : return 0;
1339 : }
1340 : module_init(slab_proc_init);
1341 :
1342 : #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
1343 :
1344 : static __always_inline __realloc_size(2) void *
1345 : __do_krealloc(const void *p, size_t new_size, gfp_t flags)
1346 : {
1347 : void *ret;
1348 : size_t ks;
1349 :
1350 : /* Check for double-free before calling ksize. */
1351 96 : if (likely(!ZERO_OR_NULL_PTR(p))) {
1352 96 : if (!kasan_check_byte(p))
1353 : return NULL;
1354 96 : ks = ksize(p);
1355 : } else
1356 : ks = 0;
1357 :
1358 : /* If the object still fits, repoison it precisely. */
1359 96 : if (ks >= new_size) {
1360 : p = kasan_krealloc((void *)p, new_size, flags);
1361 : return (void *)p;
1362 : }
1363 :
1364 76 : ret = kmalloc_track_caller(new_size, flags);
1365 76 : if (ret && p) {
1366 : /* Disable KASAN checks as the object's redzone is accessed. */
1367 : kasan_disable_current();
1368 76 : memcpy(ret, kasan_reset_tag(p), ks);
1369 : kasan_enable_current();
1370 : }
1371 :
1372 : return ret;
1373 : }
1374 :
1375 : /**
1376 : * krealloc - reallocate memory. The contents will remain unchanged.
1377 : * @p: object to reallocate memory for.
1378 : * @new_size: how many bytes of memory are required.
1379 : * @flags: the type of memory to allocate.
1380 : *
1381 : * The contents of the object pointed to are preserved up to the
1382 : * lesser of the new and old sizes (__GFP_ZERO flag is effectively ignored).
1383 : * If @p is %NULL, krealloc() behaves exactly like kmalloc(). If @new_size
1384 : * is 0 and @p is not a %NULL pointer, the object pointed to is freed.
1385 : *
1386 : * Return: pointer to the allocated memory or %NULL in case of error
1387 : */
1388 96 : void *krealloc(const void *p, size_t new_size, gfp_t flags)
1389 : {
1390 : void *ret;
1391 :
1392 96 : if (unlikely(!new_size)) {
1393 0 : kfree(p);
1394 0 : return ZERO_SIZE_PTR;
1395 : }
1396 :
1397 96 : ret = __do_krealloc(p, new_size, flags);
1398 96 : if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
1399 76 : kfree(p);
1400 :
1401 : return ret;
1402 : }
1403 : EXPORT_SYMBOL(krealloc);
1404 :
1405 : /**
1406 : * kfree_sensitive - Clear sensitive information in memory before freeing
1407 : * @p: object to free memory of
1408 : *
1409 : * The memory of the object @p points to is zeroed before freed.
1410 : * If @p is %NULL, kfree_sensitive() does nothing.
1411 : *
1412 : * Note: this function zeroes the whole allocated buffer which can be a good
1413 : * deal bigger than the requested buffer size passed to kmalloc(). So be
1414 : * careful when using this function in performance sensitive code.
1415 : */
1416 0 : void kfree_sensitive(const void *p)
1417 : {
1418 : size_t ks;
1419 0 : void *mem = (void *)p;
1420 :
1421 0 : ks = ksize(mem);
1422 0 : if (ks) {
1423 0 : kasan_unpoison_range(mem, ks);
1424 : memzero_explicit(mem, ks);
1425 : }
1426 0 : kfree(mem);
1427 0 : }
1428 : EXPORT_SYMBOL(kfree_sensitive);
1429 :
1430 113 : size_t ksize(const void *objp)
1431 : {
1432 : /*
1433 : * We need to first check that the pointer to the object is valid.
1434 : * The KASAN report printed from ksize() is more useful, then when
1435 : * it's printed later when the behaviour could be undefined due to
1436 : * a potential use-after-free or double-free.
1437 : *
1438 : * We use kasan_check_byte(), which is supported for the hardware
1439 : * tag-based KASAN mode, unlike kasan_check_read/write().
1440 : *
1441 : * If the pointed to memory is invalid, we return 0 to avoid users of
1442 : * ksize() writing to and potentially corrupting the memory region.
1443 : *
1444 : * We want to perform the check before __ksize(), to avoid potentially
1445 : * crashing in __ksize() due to accessing invalid metadata.
1446 : */
1447 113 : if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp))
1448 : return 0;
1449 :
1450 113 : return kfence_ksize(objp) ?: __ksize(objp);
1451 : }
1452 : EXPORT_SYMBOL(ksize);
1453 :
1454 : /* Tracepoints definitions. */
1455 : EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1456 : EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1457 : EXPORT_TRACEPOINT_SYMBOL(kfree);
1458 : EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1459 :
1460 420882 : int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
1461 : {
1462 420882 : if (__should_failslab(s, gfpflags))
1463 : return -ENOMEM;
1464 : return 0;
1465 : }
1466 : ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
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