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
28#define CREATE_TRACE_POINTS
29#include <trace/events/kmem.h>
30
31#include "internal.h"
32
33#include "slab.h"
34
35enum slab_state slab_state;
36LIST_HEAD(slab_caches);
37DEFINE_MUTEX(slab_mutex);
38struct kmem_cache *kmem_cache;
39
40static LIST_HEAD(slab_caches_to_rcu_destroy);
41static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
42static 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 */
58static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
59
60static int __init setup_slab_nomerge(char *str)
61{
62	slab_nomerge = true;
63	return 1;
64}
65
66static int __init setup_slab_merge(char *str)
67{
68	slab_nomerge = false;
69	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 */
83unsigned int kmem_cache_size(struct kmem_cache *s)
84{
85	return s->object_size;
86}
87EXPORT_SYMBOL(kmem_cache_size);
88
89#ifdef CONFIG_DEBUG_VM
90static 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
101static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
102{
103	return 0;
104}
105#endif
106
107void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
108{
109	size_t i;
110
111	for (i = 0; i < nr; i++) {
112		if (s)
113			kmem_cache_free(s, p[i]);
114		else
115			kfree(p[i]);
116	}
117}
118
119int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
120								void **p)
121{
122	size_t i;
123
124	for (i = 0; i < nr; i++) {
125		void *x = p[i] = kmem_cache_alloc(s, flags);
126		if (!x) {
127			__kmem_cache_free_bulk(s, i, p);
128			return 0;
129		}
130	}
131	return i;
132}
133
134/*
135 * Figure out what the alignment of the objects will be given a set of
136 * flags, a user specified alignment and the size of the objects.
137 */
138static unsigned int calculate_alignment(slab_flags_t flags,
139		unsigned int align, unsigned int size)
140{
141	/*
142	 * If the user wants hardware cache aligned objects then follow that
143	 * suggestion if the object is sufficiently large.
144	 *
145	 * The hardware cache alignment cannot override the specified
146	 * alignment though. If that is greater then use it.
147	 */
148	if (flags & SLAB_HWCACHE_ALIGN) {
149		unsigned int ralign;
150
151		ralign = cache_line_size();
152		while (size <= ralign / 2)
153			ralign /= 2;
154		align = max(align, ralign);
155	}
156
157	if (align < ARCH_SLAB_MINALIGN)
158		align = ARCH_SLAB_MINALIGN;
159
160	return ALIGN(align, sizeof(void *));
161}
162
163/*
164 * Find a mergeable slab cache
165 */
166int slab_unmergeable(struct kmem_cache *s)
167{
168	if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
169		return 1;
170
171	if (s->ctor)
172		return 1;
173
174	if (s->usersize)
175		return 1;
176
177	/*
178	 * We may have set a slab to be unmergeable during bootstrap.
179	 */
180	if (s->refcount < 0)
181		return 1;
182
183	return 0;
184}
185
186struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
187		slab_flags_t flags, const char *name, void (*ctor)(void *))
188{
189	struct kmem_cache *s;
190
191	if (slab_nomerge)
192		return NULL;
193
194	if (ctor)
195		return NULL;
196
197	size = ALIGN(size, sizeof(void *));
198	align = calculate_alignment(flags, align, size);
199	size = ALIGN(size, align);
200	flags = kmem_cache_flags(size, flags, name);
201
202	if (flags & SLAB_NEVER_MERGE)
203		return NULL;
204
205	list_for_each_entry_reverse(s, &slab_caches, list) {
206		if (slab_unmergeable(s))
207			continue;
208
209		if (size > s->size)
210			continue;
211
212		if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
213			continue;
214		/*
215		 * Check if alignment is compatible.
216		 * Courtesy of Adrian Drzewiecki
217		 */
218		if ((s->size & ~(align - 1)) != s->size)
219			continue;
220
221		if (s->size - size >= sizeof(void *))
222			continue;
223
224		if (IS_ENABLED(CONFIG_SLAB) && align &&
225			(align > s->align || s->align % align))
226			continue;
227
228		return s;
229	}
230	return NULL;
231}
232
233static struct kmem_cache *create_cache(const char *name,
234		unsigned int object_size, unsigned int align,
235		slab_flags_t flags, unsigned int useroffset,
236		unsigned int usersize, void (*ctor)(void *),
237		struct kmem_cache *root_cache)
238{
239	struct kmem_cache *s;
240	int err;
241
242	if (WARN_ON(useroffset + usersize > object_size))
243		useroffset = usersize = 0;
244
245	err = -ENOMEM;
246	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
247	if (!s)
248		goto out;
249
250	s->name = name;
251	s->size = s->object_size = object_size;
252	s->align = align;
253	s->ctor = ctor;
254	s->useroffset = useroffset;
255	s->usersize = usersize;
256
257	err = __kmem_cache_create(s, flags);
258	if (err)
259		goto out_free_cache;
260
261	s->refcount = 1;
262	list_add(&s->list, &slab_caches);
263out:
264	if (err)
265		return ERR_PTR(err);
266	return s;
267
268out_free_cache:
269	kmem_cache_free(kmem_cache, s);
270	goto out;
271}
272
273/**
274 * kmem_cache_create_usercopy - Create a cache with a region suitable
275 * for copying to userspace
276 * @name: A string which is used in /proc/slabinfo to identify this cache.
277 * @size: The size of objects to be created in this cache.
278 * @align: The required alignment for the objects.
279 * @flags: SLAB flags
280 * @useroffset: Usercopy region offset
281 * @usersize: Usercopy region size
282 * @ctor: A constructor for the objects.
283 *
284 * Cannot be called within a interrupt, but can be interrupted.
285 * The @ctor is run when new pages are allocated by the cache.
286 *
287 * The flags are
288 *
289 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
290 * to catch references to uninitialised memory.
291 *
292 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
293 * for buffer overruns.
294 *
295 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
296 * cacheline.  This can be beneficial if you're counting cycles as closely
297 * as davem.
298 *
299 * Return: a pointer to the cache on success, NULL on failure.
300 */
301struct kmem_cache *
302kmem_cache_create_usercopy(const char *name,
303		  unsigned int size, unsigned int align,
304		  slab_flags_t flags,
305		  unsigned int useroffset, unsigned int usersize,
306		  void (*ctor)(void *))
307{
308	struct kmem_cache *s = NULL;
309	const char *cache_name;
310	int err;
311
312#ifdef CONFIG_SLUB_DEBUG
313	/*
314	 * If no slub_debug was enabled globally, the static key is not yet
315	 * enabled by setup_slub_debug(). Enable it if the cache is being
316	 * created with any of the debugging flags passed explicitly.
317	 */
318	if (flags & SLAB_DEBUG_FLAGS)
319		static_branch_enable(&slub_debug_enabled);
320#endif
321
322	mutex_lock(&slab_mutex);
323
324	err = kmem_cache_sanity_check(name, size);
325	if (err) {
326		goto out_unlock;
327	}
328
329	/* Refuse requests with allocator specific flags */
330	if (flags & ~SLAB_FLAGS_PERMITTED) {
331		err = -EINVAL;
332		goto out_unlock;
333	}
334
335	/*
336	 * Some allocators will constraint the set of valid flags to a subset
337	 * of all flags. We expect them to define CACHE_CREATE_MASK in this
338	 * case, and we'll just provide them with a sanitized version of the
339	 * passed flags.
340	 */
341	flags &= CACHE_CREATE_MASK;
342
343	/* Fail closed on bad usersize of useroffset values. */
344	if (WARN_ON(!usersize && useroffset) ||
345	    WARN_ON(size < usersize || size - usersize < useroffset))
346		usersize = useroffset = 0;
347
348	if (!usersize)
349		s = __kmem_cache_alias(name, size, align, flags, ctor);
350	if (s)
351		goto out_unlock;
352
353	cache_name = kstrdup_const(name, GFP_KERNEL);
354	if (!cache_name) {
355		err = -ENOMEM;
356		goto out_unlock;
357	}
358
359	s = create_cache(cache_name, size,
360			 calculate_alignment(flags, align, size),
361			 flags, useroffset, usersize, ctor, NULL);
362	if (IS_ERR(s)) {
363		err = PTR_ERR(s);
364		kfree_const(cache_name);
365	}
366
367out_unlock:
368	mutex_unlock(&slab_mutex);
369
370	if (err) {
371		if (flags & SLAB_PANIC)
372			panic("%s: Failed to create slab '%s'. Error %d\n",
373				__func__, name, err);
374		else {
375			pr_warn("%s(%s) failed with error %d\n",
376				__func__, name, err);
377			dump_stack();
378		}
379		return NULL;
380	}
381	return s;
382}
383EXPORT_SYMBOL(kmem_cache_create_usercopy);
384
385/**
386 * kmem_cache_create - Create a cache.
387 * @name: A string which is used in /proc/slabinfo to identify this cache.
388 * @size: The size of objects to be created in this cache.
389 * @align: The required alignment for the objects.
390 * @flags: SLAB flags
391 * @ctor: A constructor for the objects.
392 *
393 * Cannot be called within a interrupt, but can be interrupted.
394 * The @ctor is run when new pages are allocated by the cache.
395 *
396 * The flags are
397 *
398 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
399 * to catch references to uninitialised memory.
400 *
401 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
402 * for buffer overruns.
403 *
404 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
405 * cacheline.  This can be beneficial if you're counting cycles as closely
406 * as davem.
407 *
408 * Return: a pointer to the cache on success, NULL on failure.
409 */
410struct kmem_cache *
411kmem_cache_create(const char *name, unsigned int size, unsigned int align,
412		slab_flags_t flags, void (*ctor)(void *))
413{
414	return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
415					  ctor);
416}
417EXPORT_SYMBOL(kmem_cache_create);
418
419static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
420{
421	LIST_HEAD(to_destroy);
422	struct kmem_cache *s, *s2;
423
424	/*
425	 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
426	 * @slab_caches_to_rcu_destroy list.  The slab pages are freed
427	 * through RCU and the associated kmem_cache are dereferenced
428	 * while freeing the pages, so the kmem_caches should be freed only
429	 * after the pending RCU operations are finished.  As rcu_barrier()
430	 * is a pretty slow operation, we batch all pending destructions
431	 * asynchronously.
432	 */
433	mutex_lock(&slab_mutex);
434	list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
435	mutex_unlock(&slab_mutex);
436
437	if (list_empty(&to_destroy))
438		return;
439
440	rcu_barrier();
441
442	list_for_each_entry_safe(s, s2, &to_destroy, list) {
443		debugfs_slab_release(s);
444		kfence_shutdown_cache(s);
445#ifdef SLAB_SUPPORTS_SYSFS
446		sysfs_slab_release(s);
447#else
448		slab_kmem_cache_release(s);
449#endif
450	}
451}
452
453static int shutdown_cache(struct kmem_cache *s)
454{
455	/* free asan quarantined objects */
456	kasan_cache_shutdown(s);
457
458	if (__kmem_cache_shutdown(s) != 0)
459		return -EBUSY;
460
461	list_del(&s->list);
462
463	if (s->flags & SLAB_TYPESAFE_BY_RCU) {
464#ifdef SLAB_SUPPORTS_SYSFS
465		sysfs_slab_unlink(s);
466#endif
467		list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
468		schedule_work(&slab_caches_to_rcu_destroy_work);
469	} else {
470		kfence_shutdown_cache(s);
471		debugfs_slab_release(s);
472#ifdef SLAB_SUPPORTS_SYSFS
473		sysfs_slab_unlink(s);
474		sysfs_slab_release(s);
475#else
476		slab_kmem_cache_release(s);
477#endif
478	}
479
480	return 0;
481}
482
483void slab_kmem_cache_release(struct kmem_cache *s)
484{
485	__kmem_cache_release(s);
486	kfree_const(s->name);
487	kmem_cache_free(kmem_cache, s);
488}
489
490void kmem_cache_destroy(struct kmem_cache *s)
491{
492	if (unlikely(!s) || !kasan_check_byte(s))
493		return;
494
495	cpus_read_lock();
496	mutex_lock(&slab_mutex);
497
498	s->refcount--;
499	if (s->refcount)
500		goto out_unlock;
501
502	WARN(shutdown_cache(s),
503	     "%s %s: Slab cache still has objects when called from %pS",
504	     __func__, s->name, (void *)_RET_IP_);
505out_unlock:
506	mutex_unlock(&slab_mutex);
507	cpus_read_unlock();
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
525	kasan_cache_shrink(cachep);
526	ret = __kmem_cache_shrink(cachep);
527
528	return ret;
529}
530EXPORT_SYMBOL(kmem_cache_shrink);
531
532bool slab_is_available(void)
533{
534	return slab_state >= UP;
535}
536
537#ifdef CONFIG_PRINTK
538/**
539 * kmem_valid_obj - does the pointer reference a valid slab object?
540 * @object: pointer to query.
541 *
542 * Return: %true if the pointer is to a not-yet-freed object from
543 * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer
544 * is to an already-freed object, and %false otherwise.
545 */
546bool kmem_valid_obj(void *object)
547{
548	struct folio *folio;
549
550	/* Some arches consider ZERO_SIZE_PTR to be a valid address. */
551	if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
552		return false;
553	folio = virt_to_folio(object);
554	return folio_test_slab(folio);
555}
556EXPORT_SYMBOL_GPL(kmem_valid_obj);
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 */
573void kmem_dump_obj(void *object)
574{
575	char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
576	int i;
577	struct slab *slab;
578	unsigned long ptroffset;
579	struct kmem_obj_info kp = { };
580
581	if (WARN_ON_ONCE(!virt_addr_valid(object)))
582		return;
583	slab = virt_to_slab(object);
584	if (WARN_ON_ONCE(!slab)) {
585		pr_cont(" non-slab memory.\n");
586		return;
587	}
588	kmem_obj_info(&kp, object, slab);
589	if (kp.kp_slab_cache)
590		pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name);
591	else
592		pr_cont(" slab%s", cp);
593	if (kp.kp_objp)
594		pr_cont(" start %px", kp.kp_objp);
595	if (kp.kp_data_offset)
596		pr_cont(" data offset %lu", kp.kp_data_offset);
597	if (kp.kp_objp) {
598		ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset;
599		pr_cont(" pointer offset %lu", ptroffset);
600	}
601	if (kp.kp_slab_cache && kp.kp_slab_cache->usersize)
602		pr_cont(" size %u", kp.kp_slab_cache->usersize);
603	if (kp.kp_ret)
604		pr_cont(" allocated at %pS\n", kp.kp_ret);
605	else
606		pr_cont("\n");
607	for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) {
608		if (!kp.kp_stack[i])
609			break;
610		pr_info("    %pS\n", kp.kp_stack[i]);
611	}
612
613	if (kp.kp_free_stack[0])
614		pr_cont(" Free path:\n");
615
616	for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) {
617		if (!kp.kp_free_stack[i])
618			break;
619		pr_info("    %pS\n", kp.kp_free_stack[i]);
620	}
621
622}
623EXPORT_SYMBOL_GPL(kmem_dump_obj);
624#endif
625
626#ifndef CONFIG_SLOB
627/* Create a cache during boot when no slab services are available yet */
628void __init create_boot_cache(struct kmem_cache *s, const char *name,
629		unsigned int size, slab_flags_t flags,
630		unsigned int useroffset, unsigned int usersize)
631{
632	int err;
633	unsigned int align = ARCH_KMALLOC_MINALIGN;
634
635	s->name = name;
636	s->size = s->object_size = size;
637
638	/*
639	 * For power of two sizes, guarantee natural alignment for kmalloc
640	 * caches, regardless of SL*B debugging options.
641	 */
642	if (is_power_of_2(size))
643		align = max(align, size);
644	s->align = calculate_alignment(flags, align, size);
645
646	s->useroffset = useroffset;
647	s->usersize = usersize;
648
649	err = __kmem_cache_create(s, flags);
650
651	if (err)
652		panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
653					name, size, err);
654
655	s->refcount = -1;	/* Exempt from merging for now */
656}
657
658struct kmem_cache *__init create_kmalloc_cache(const char *name,
659		unsigned int size, slab_flags_t flags,
660		unsigned int useroffset, unsigned int usersize)
661{
662	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
663
664	if (!s)
665		panic("Out of memory when creating slab %s\n", name);
666
667	create_boot_cache(s, name, size, flags, useroffset, usersize);
668	kasan_cache_create_kmalloc(s);
669	list_add(&s->list, &slab_caches);
670	s->refcount = 1;
671	return s;
672}
673
674struct kmem_cache *
675kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
676{ /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
677EXPORT_SYMBOL(kmalloc_caches);
678
679/*
680 * Conversion table for small slabs sizes / 8 to the index in the
681 * kmalloc array. This is necessary for slabs < 192 since we have non power
682 * of two cache sizes there. The size of larger slabs can be determined using
683 * fls.
684 */
685static u8 size_index[24] __ro_after_init = {
686	3,	/* 8 */
687	4,	/* 16 */
688	5,	/* 24 */
689	5,	/* 32 */
690	6,	/* 40 */
691	6,	/* 48 */
692	6,	/* 56 */
693	6,	/* 64 */
694	1,	/* 72 */
695	1,	/* 80 */
696	1,	/* 88 */
697	1,	/* 96 */
698	7,	/* 104 */
699	7,	/* 112 */
700	7,	/* 120 */
701	7,	/* 128 */
702	2,	/* 136 */
703	2,	/* 144 */
704	2,	/* 152 */
705	2,	/* 160 */
706	2,	/* 168 */
707	2,	/* 176 */
708	2,	/* 184 */
709	2	/* 192 */
710};
711
712static inline unsigned int size_index_elem(unsigned int bytes)
713{
714	return (bytes - 1) / 8;
715}
716
717/*
718 * Find the kmem_cache structure that serves a given size of
719 * allocation
720 */
721struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
722{
723	unsigned int index;
724
725	if (size <= 192) {
726		if (!size)
727			return ZERO_SIZE_PTR;
728
729		index = size_index[size_index_elem(size)];
730	} else {
731		if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
732			return NULL;
733		index = fls(size - 1);
734	}
735
736	return kmalloc_caches[kmalloc_type(flags)][index];
737}
738
739#ifdef CONFIG_ZONE_DMA
740#define KMALLOC_DMA_NAME(sz)	.name[KMALLOC_DMA] = "dma-kmalloc-" #sz,
741#else
742#define KMALLOC_DMA_NAME(sz)
743#endif
744
745#ifdef CONFIG_MEMCG_KMEM
746#define KMALLOC_CGROUP_NAME(sz)	.name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz,
747#else
748#define KMALLOC_CGROUP_NAME(sz)
749#endif
750
751#define INIT_KMALLOC_INFO(__size, __short_size)			\
752{								\
753	.name[KMALLOC_NORMAL]  = "kmalloc-" #__short_size,	\
754	.name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size,	\
755	KMALLOC_CGROUP_NAME(__short_size)			\
756	KMALLOC_DMA_NAME(__short_size)				\
757	.size = __size,						\
758}
759
760/*
761 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
762 * kmalloc_index() supports up to 2^25=32MB, so the final entry of the table is
763 * kmalloc-32M.
764 */
765const struct kmalloc_info_struct kmalloc_info[] __initconst = {
766	INIT_KMALLOC_INFO(0, 0),
767	INIT_KMALLOC_INFO(96, 96),
768	INIT_KMALLOC_INFO(192, 192),
769	INIT_KMALLOC_INFO(8, 8),
770	INIT_KMALLOC_INFO(16, 16),
771	INIT_KMALLOC_INFO(32, 32),
772	INIT_KMALLOC_INFO(64, 64),
773	INIT_KMALLOC_INFO(128, 128),
774	INIT_KMALLOC_INFO(256, 256),
775	INIT_KMALLOC_INFO(512, 512),
776	INIT_KMALLOC_INFO(1024, 1k),
777	INIT_KMALLOC_INFO(2048, 2k),
778	INIT_KMALLOC_INFO(4096, 4k),
779	INIT_KMALLOC_INFO(8192, 8k),
780	INIT_KMALLOC_INFO(16384, 16k),
781	INIT_KMALLOC_INFO(32768, 32k),
782	INIT_KMALLOC_INFO(65536, 64k),
783	INIT_KMALLOC_INFO(131072, 128k),
784	INIT_KMALLOC_INFO(262144, 256k),
785	INIT_KMALLOC_INFO(524288, 512k),
786	INIT_KMALLOC_INFO(1048576, 1M),
787	INIT_KMALLOC_INFO(2097152, 2M),
788	INIT_KMALLOC_INFO(4194304, 4M),
789	INIT_KMALLOC_INFO(8388608, 8M),
790	INIT_KMALLOC_INFO(16777216, 16M),
791	INIT_KMALLOC_INFO(33554432, 32M)
792};
793
794/*
795 * Patch up the size_index table if we have strange large alignment
796 * requirements for the kmalloc array. This is only the case for
797 * MIPS it seems. The standard arches will not generate any code here.
798 *
799 * Largest permitted alignment is 256 bytes due to the way we
800 * handle the index determination for the smaller caches.
801 *
802 * Make sure that nothing crazy happens if someone starts tinkering
803 * around with ARCH_KMALLOC_MINALIGN
804 */
805void __init setup_kmalloc_cache_index_table(void)
806{
807	unsigned int i;
808
809	BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
810		(KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
811
812	for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
813		unsigned int elem = size_index_elem(i);
814
815		if (elem >= ARRAY_SIZE(size_index))
816			break;
817		size_index[elem] = KMALLOC_SHIFT_LOW;
818	}
819
820	if (KMALLOC_MIN_SIZE >= 64) {
821		/*
822		 * The 96 byte sized cache is not used if the alignment
823		 * is 64 byte.
824		 */
825		for (i = 64 + 8; i <= 96; i += 8)
826			size_index[size_index_elem(i)] = 7;
827
828	}
829
830	if (KMALLOC_MIN_SIZE >= 128) {
831		/*
832		 * The 192 byte sized cache is not used if the alignment
833		 * is 128 byte. Redirect kmalloc to use the 256 byte cache
834		 * instead.
835		 */
836		for (i = 128 + 8; i <= 192; i += 8)
837			size_index[size_index_elem(i)] = 8;
838	}
839}
840
841static void __init
842new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
843{
844	if (type == KMALLOC_RECLAIM) {
845		flags |= SLAB_RECLAIM_ACCOUNT;
846	} else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) {
847		if (mem_cgroup_kmem_disabled()) {
848			kmalloc_caches[type][idx] = kmalloc_caches[KMALLOC_NORMAL][idx];
849			return;
850		}
851		flags |= SLAB_ACCOUNT;
852	}
853
854	kmalloc_caches[type][idx] = create_kmalloc_cache(
855					kmalloc_info[idx].name[type],
856					kmalloc_info[idx].size, flags, 0,
857					kmalloc_info[idx].size);
858
859	/*
860	 * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for
861	 * KMALLOC_NORMAL caches.
862	 */
863	if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_NORMAL))
864		kmalloc_caches[type][idx]->refcount = -1;
865}
866
867/*
868 * Create the kmalloc array. Some of the regular kmalloc arrays
869 * may already have been created because they were needed to
870 * enable allocations for slab creation.
871 */
872void __init create_kmalloc_caches(slab_flags_t flags)
873{
874	int i;
875	enum kmalloc_cache_type type;
876
877	/*
878	 * Including KMALLOC_CGROUP if CONFIG_MEMCG_KMEM defined
879	 */
880	for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
881		for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
882			if (!kmalloc_caches[type][i])
883				new_kmalloc_cache(i, type, flags);
884
885			/*
886			 * Caches that are not of the two-to-the-power-of size.
887			 * These have to be created immediately after the
888			 * earlier power of two caches
889			 */
890			if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
891					!kmalloc_caches[type][1])
892				new_kmalloc_cache(1, type, flags);
893			if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
894					!kmalloc_caches[type][2])
895				new_kmalloc_cache(2, type, flags);
896		}
897	}
898
899	/* Kmalloc array is now usable */
900	slab_state = UP;
901
902#ifdef CONFIG_ZONE_DMA
903	for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
904		struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
905
906		if (s) {
907			kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
908				kmalloc_info[i].name[KMALLOC_DMA],
909				kmalloc_info[i].size,
910				SLAB_CACHE_DMA | flags, 0,
911				kmalloc_info[i].size);
912		}
913	}
914#endif
915}
916#endif /* !CONFIG_SLOB */
917
918gfp_t kmalloc_fix_flags(gfp_t flags)
919{
920	gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
921
922	flags &= ~GFP_SLAB_BUG_MASK;
923	pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
924			invalid_mask, &invalid_mask, flags, &flags);
925	dump_stack();
926
927	return flags;
928}
929
930/*
931 * To avoid unnecessary overhead, we pass through large allocation requests
932 * directly to the page allocator. We use __GFP_COMP, because we will need to
933 * know the allocation order to free the pages properly in kfree.
934 */
935void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
936{
937	void *ret = NULL;
938	struct page *page;
939
940	if (unlikely(flags & GFP_SLAB_BUG_MASK))
941		flags = kmalloc_fix_flags(flags);
942
943	flags |= __GFP_COMP;
944	page = alloc_pages(flags, order);
945	if (likely(page)) {
946		ret = page_address(page);
947		mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
948				      PAGE_SIZE << order);
949	}
950	ret = kasan_kmalloc_large(ret, size, flags);
951	/* As ret might get tagged, call kmemleak hook after KASAN. */
952	kmemleak_alloc(ret, size, 1, flags);
953	return ret;
954}
955EXPORT_SYMBOL(kmalloc_order);
956
957#ifdef CONFIG_TRACING
958void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
959{
960	void *ret = kmalloc_order(size, flags, order);
961	trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
962	return ret;
963}
964EXPORT_SYMBOL(kmalloc_order_trace);
965#endif
966
967#ifdef CONFIG_SLAB_FREELIST_RANDOM
968/* Randomize a generic freelist */
969static void freelist_randomize(struct rnd_state *state, unsigned int *list,
970			       unsigned int count)
971{
972	unsigned int rand;
973	unsigned int i;
974
975	for (i = 0; i < count; i++)
976		list[i] = i;
977
978	/* Fisher-Yates shuffle */
979	for (i = count - 1; i > 0; i--) {
980		rand = prandom_u32_state(state);
981		rand %= (i + 1);
982		swap(list[i], list[rand]);
983	}
984}
985
986/* Create a random sequence per cache */
987int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
988				    gfp_t gfp)
989{
990	struct rnd_state state;
991
992	if (count < 2 || cachep->random_seq)
993		return 0;
994
995	cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
996	if (!cachep->random_seq)
997		return -ENOMEM;
998
999	/* Get best entropy at this stage of boot */
1000	prandom_seed_state(&state, get_random_long());
1001
1002	freelist_randomize(&state, cachep->random_seq, count);
1003	return 0;
1004}
1005
1006/* Destroy the per-cache random freelist sequence */
1007void cache_random_seq_destroy(struct kmem_cache *cachep)
1008{
1009	kfree(cachep->random_seq);
1010	cachep->random_seq = NULL;
1011}
1012#endif /* CONFIG_SLAB_FREELIST_RANDOM */
1013
1014#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
1015#ifdef CONFIG_SLAB
1016#define SLABINFO_RIGHTS (0600)
1017#else
1018#define SLABINFO_RIGHTS (0400)
1019#endif
1020
1021static void print_slabinfo_header(struct seq_file *m)
1022{
1023	/*
1024	 * Output format version, so at least we can change it
1025	 * without _too_ many complaints.
1026	 */
1027#ifdef CONFIG_DEBUG_SLAB
1028	seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
1029#else
1030	seq_puts(m, "slabinfo - version: 2.1\n");
1031#endif
1032	seq_puts(m, "# name            <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
1033	seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
1034	seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
1035#ifdef CONFIG_DEBUG_SLAB
1036	seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
1037	seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
1038#endif
1039	seq_putc(m, '\n');
1040}
1041
1042static void *slab_start(struct seq_file *m, loff_t *pos)
1043{
1044	mutex_lock(&slab_mutex);
1045	return seq_list_start(&slab_caches, *pos);
1046}
1047
1048static void *slab_next(struct seq_file *m, void *p, loff_t *pos)
1049{
1050	return seq_list_next(p, &slab_caches, pos);
1051}
1052
1053static void slab_stop(struct seq_file *m, void *p)
1054{
1055	mutex_unlock(&slab_mutex);
1056}
1057
1058static void cache_show(struct kmem_cache *s, struct seq_file *m)
1059{
1060	struct slabinfo sinfo;
1061
1062	memset(&sinfo, 0, sizeof(sinfo));
1063	get_slabinfo(s, &sinfo);
1064
1065	seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
1066		   s->name, sinfo.active_objs, sinfo.num_objs, s->size,
1067		   sinfo.objects_per_slab, (1 << sinfo.cache_order));
1068
1069	seq_printf(m, " : tunables %4u %4u %4u",
1070		   sinfo.limit, sinfo.batchcount, sinfo.shared);
1071	seq_printf(m, " : slabdata %6lu %6lu %6lu",
1072		   sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
1073	slabinfo_show_stats(m, s);
1074	seq_putc(m, '\n');
1075}
1076
1077static int slab_show(struct seq_file *m, void *p)
1078{
1079	struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
1080
1081	if (p == slab_caches.next)
1082		print_slabinfo_header(m);
1083	cache_show(s, m);
1084	return 0;
1085}
1086
1087void dump_unreclaimable_slab(void)
1088{
1089	struct kmem_cache *s;
1090	struct slabinfo sinfo;
1091
1092	/*
1093	 * Here acquiring slab_mutex is risky since we don't prefer to get
1094	 * sleep in oom path. But, without mutex hold, it may introduce a
1095	 * risk of crash.
1096	 * Use mutex_trylock to protect the list traverse, dump nothing
1097	 * without acquiring the mutex.
1098	 */
1099	if (!mutex_trylock(&slab_mutex)) {
1100		pr_warn("excessive unreclaimable slab but cannot dump stats\n");
1101		return;
1102	}
1103
1104	pr_info("Unreclaimable slab info:\n");
1105	pr_info("Name                      Used          Total\n");
1106
1107	list_for_each_entry(s, &slab_caches, list) {
1108		if (s->flags & SLAB_RECLAIM_ACCOUNT)
1109			continue;
1110
1111		get_slabinfo(s, &sinfo);
1112
1113		if (sinfo.num_objs > 0)
1114			pr_info("%-17s %10luKB %10luKB\n", s->name,
1115				(sinfo.active_objs * s->size) / 1024,
1116				(sinfo.num_objs * s->size) / 1024);
1117	}
1118	mutex_unlock(&slab_mutex);
1119}
1120
1121/*
1122 * slabinfo_op - iterator that generates /proc/slabinfo
1123 *
1124 * Output layout:
1125 * cache-name
1126 * num-active-objs
1127 * total-objs
1128 * object size
1129 * num-active-slabs
1130 * total-slabs
1131 * num-pages-per-slab
1132 * + further values on SMP and with statistics enabled
1133 */
1134static const struct seq_operations slabinfo_op = {
1135	.start = slab_start,
1136	.next = slab_next,
1137	.stop = slab_stop,
1138	.show = slab_show,
1139};
1140
1141static int slabinfo_open(struct inode *inode, struct file *file)
1142{
1143	return seq_open(file, &slabinfo_op);
1144}
1145
1146static const struct proc_ops slabinfo_proc_ops = {
1147	.proc_flags	= PROC_ENTRY_PERMANENT,
1148	.proc_open	= slabinfo_open,
1149	.proc_read	= seq_read,
1150	.proc_write	= slabinfo_write,
1151	.proc_lseek	= seq_lseek,
1152	.proc_release	= seq_release,
1153};
1154
1155static int __init slab_proc_init(void)
1156{
1157	proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
1158	return 0;
1159}
1160module_init(slab_proc_init);
1161
1162#endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
1163
1164static __always_inline void *__do_krealloc(const void *p, size_t new_size,
1165					   gfp_t flags)
1166{
1167	void *ret;
1168	size_t ks;
1169
1170	/* Don't use instrumented ksize to allow precise KASAN poisoning. */
1171	if (likely(!ZERO_OR_NULL_PTR(p))) {
1172		if (!kasan_check_byte(p))
1173			return NULL;
1174		ks = kfence_ksize(p) ?: __ksize(p);
1175	} else
1176		ks = 0;
1177
1178	/* If the object still fits, repoison it precisely. */
1179	if (ks >= new_size) {
1180		p = kasan_krealloc((void *)p, new_size, flags);
1181		return (void *)p;
1182	}
1183
1184	ret = kmalloc_track_caller(new_size, flags);
1185	if (ret && p) {
1186		/* Disable KASAN checks as the object's redzone is accessed. */
1187		kasan_disable_current();
1188		memcpy(ret, kasan_reset_tag(p), ks);
1189		kasan_enable_current();
1190	}
1191
1192	return ret;
1193}
1194
1195/**
1196 * krealloc - reallocate memory. The contents will remain unchanged.
1197 * @p: object to reallocate memory for.
1198 * @new_size: how many bytes of memory are required.
1199 * @flags: the type of memory to allocate.
1200 *
1201 * The contents of the object pointed to are preserved up to the
1202 * lesser of the new and old sizes (__GFP_ZERO flag is effectively ignored).
1203 * If @p is %NULL, krealloc() behaves exactly like kmalloc().  If @new_size
1204 * is 0 and @p is not a %NULL pointer, the object pointed to is freed.
1205 *
1206 * Return: pointer to the allocated memory or %NULL in case of error
1207 */
1208void *krealloc(const void *p, size_t new_size, gfp_t flags)
1209{
1210	void *ret;
1211
1212	if (unlikely(!new_size)) {
1213		kfree(p);
1214		return ZERO_SIZE_PTR;
1215	}
1216
1217	ret = __do_krealloc(p, new_size, flags);
1218	if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
1219		kfree(p);
1220
1221	return ret;
1222}
1223EXPORT_SYMBOL(krealloc);
1224
1225/**
1226 * kfree_sensitive - Clear sensitive information in memory before freeing
1227 * @p: object to free memory of
1228 *
1229 * The memory of the object @p points to is zeroed before freed.
1230 * If @p is %NULL, kfree_sensitive() does nothing.
1231 *
1232 * Note: this function zeroes the whole allocated buffer which can be a good
1233 * deal bigger than the requested buffer size passed to kmalloc(). So be
1234 * careful when using this function in performance sensitive code.
1235 */
1236void kfree_sensitive(const void *p)
1237{
1238	size_t ks;
1239	void *mem = (void *)p;
1240
1241	ks = ksize(mem);
1242	if (ks)
1243		memzero_explicit(mem, ks);
1244	kfree(mem);
1245}
1246EXPORT_SYMBOL(kfree_sensitive);
1247
1248/**
1249 * ksize - get the actual amount of memory allocated for a given object
1250 * @objp: Pointer to the object
1251 *
1252 * kmalloc may internally round up allocations and return more memory
1253 * than requested. ksize() can be used to determine the actual amount of
1254 * memory allocated. The caller may use this additional memory, even though
1255 * a smaller amount of memory was initially specified with the kmalloc call.
1256 * The caller must guarantee that objp points to a valid object previously
1257 * allocated with either kmalloc() or kmem_cache_alloc(). The object
1258 * must not be freed during the duration of the call.
1259 *
1260 * Return: size of the actual memory used by @objp in bytes
1261 */
1262size_t ksize(const void *objp)
1263{
1264	size_t size;
1265
1266	/*
1267	 * We need to first check that the pointer to the object is valid, and
1268	 * only then unpoison the memory. The report printed from ksize() is
1269	 * more useful, then when it's printed later when the behaviour could
1270	 * be undefined due to a potential use-after-free or double-free.
1271	 *
1272	 * We use kasan_check_byte(), which is supported for the hardware
1273	 * tag-based KASAN mode, unlike kasan_check_read/write().
1274	 *
1275	 * If the pointed to memory is invalid, we return 0 to avoid users of
1276	 * ksize() writing to and potentially corrupting the memory region.
1277	 *
1278	 * We want to perform the check before __ksize(), to avoid potentially
1279	 * crashing in __ksize() due to accessing invalid metadata.
1280	 */
1281	if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp))
1282		return 0;
1283
1284	size = kfence_ksize(objp) ?: __ksize(objp);
1285	/*
1286	 * We assume that ksize callers could use whole allocated area,
1287	 * so we need to unpoison this area.
1288	 */
1289	kasan_unpoison_range(objp, size);
1290	return size;
1291}
1292EXPORT_SYMBOL(ksize);
1293
1294/* Tracepoints definitions. */
1295EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1296EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1297EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
1298EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
1299EXPORT_TRACEPOINT_SYMBOL(kfree);
1300EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1301
1302int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
1303{
1304	if (__should_failslab(s, gfpflags))
1305		return -ENOMEM;
1306	return 0;
1307}
1308ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
1309