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