1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Slab allocator functions that are independent of the allocator strategy 4 * 5 * (C) 2012 Christoph Lameter <cl@linux.com> 6 */ 7 #include <linux/slab.h> 8 9 #include <linux/mm.h> 10 #include <linux/poison.h> 11 #include <linux/interrupt.h> 12 #include <linux/memory.h> 13 #include <linux/cache.h> 14 #include <linux/compiler.h> 15 #include <linux/kfence.h> 16 #include <linux/module.h> 17 #include <linux/cpu.h> 18 #include <linux/uaccess.h> 19 #include <linux/seq_file.h> 20 #include <linux/dma-mapping.h> 21 #include <linux/swiotlb.h> 22 #include <linux/proc_fs.h> 23 #include <linux/debugfs.h> 24 #include <linux/kasan.h> 25 #include <asm/cacheflush.h> 26 #include <asm/tlbflush.h> 27 #include <asm/page.h> 28 #include <linux/memcontrol.h> 29 #include <linux/stackdepot.h> 30 31 #include "internal.h" 32 #include "slab.h" 33 34 #define CREATE_TRACE_POINTS 35 #include <trace/events/kmem.h> 36 37 enum slab_state slab_state; 38 LIST_HEAD(slab_caches); 39 DEFINE_MUTEX(slab_mutex); 40 struct kmem_cache *kmem_cache; 41 42 static LIST_HEAD(slab_caches_to_rcu_destroy); 43 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work); 44 static DECLARE_WORK(slab_caches_to_rcu_destroy_work, 45 slab_caches_to_rcu_destroy_workfn); 46 47 /* 48 * Set of flags that will prevent slab merging 49 */ 50 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ 51 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \ 52 SLAB_FAILSLAB | SLAB_NO_MERGE | kasan_never_merge()) 53 54 #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \ 55 SLAB_CACHE_DMA32 | SLAB_ACCOUNT) 56 57 /* 58 * Merge control. If this is set then no merging of slab caches will occur. 59 */ 60 static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT); 61 62 static int __init setup_slab_nomerge(char *str) 63 { 64 slab_nomerge = true; 65 return 1; 66 } 67 68 static int __init setup_slab_merge(char *str) 69 { 70 slab_nomerge = false; 71 return 1; 72 } 73 74 #ifdef CONFIG_SLUB 75 __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0); 76 __setup_param("slub_merge", slub_merge, setup_slab_merge, 0); 77 #endif 78 79 __setup("slab_nomerge", setup_slab_nomerge); 80 __setup("slab_merge", setup_slab_merge); 81 82 /* 83 * Determine the size of a slab object 84 */ 85 unsigned int kmem_cache_size(struct kmem_cache *s) 86 { 87 return s->object_size; 88 } 89 EXPORT_SYMBOL(kmem_cache_size); 90 91 #ifdef CONFIG_DEBUG_VM 92 static int kmem_cache_sanity_check(const char *name, unsigned int size) 93 { 94 if (!name || in_interrupt() || size > KMALLOC_MAX_SIZE) { 95 pr_err("kmem_cache_create(%s) integrity check failed\n", name); 96 return -EINVAL; 97 } 98 99 WARN_ON(strchr(name, ' ')); /* It confuses parsers */ 100 return 0; 101 } 102 #else 103 static inline int kmem_cache_sanity_check(const char *name, unsigned int size) 104 { 105 return 0; 106 } 107 #endif 108 109 /* 110 * Figure out what the alignment of the objects will be given a set of 111 * flags, a user specified alignment and the size of the objects. 112 */ 113 static unsigned int calculate_alignment(slab_flags_t flags, 114 unsigned int align, unsigned int size) 115 { 116 /* 117 * If the user wants hardware cache aligned objects then follow that 118 * suggestion if the object is sufficiently large. 119 * 120 * The hardware cache alignment cannot override the specified 121 * alignment though. If that is greater then use it. 122 */ 123 if (flags & SLAB_HWCACHE_ALIGN) { 124 unsigned int ralign; 125 126 ralign = cache_line_size(); 127 while (size <= ralign / 2) 128 ralign /= 2; 129 align = max(align, ralign); 130 } 131 132 align = max(align, arch_slab_minalign()); 133 134 return ALIGN(align, sizeof(void *)); 135 } 136 137 /* 138 * Find a mergeable slab cache 139 */ 140 int slab_unmergeable(struct kmem_cache *s) 141 { 142 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE)) 143 return 1; 144 145 if (s->ctor) 146 return 1; 147 148 #ifdef CONFIG_HARDENED_USERCOPY 149 if (s->usersize) 150 return 1; 151 #endif 152 153 /* 154 * We may have set a slab to be unmergeable during bootstrap. 155 */ 156 if (s->refcount < 0) 157 return 1; 158 159 return 0; 160 } 161 162 struct kmem_cache *find_mergeable(unsigned int size, unsigned int align, 163 slab_flags_t flags, const char *name, void (*ctor)(void *)) 164 { 165 struct kmem_cache *s; 166 167 if (slab_nomerge) 168 return NULL; 169 170 if (ctor) 171 return NULL; 172 173 size = ALIGN(size, sizeof(void *)); 174 align = calculate_alignment(flags, align, size); 175 size = ALIGN(size, align); 176 flags = kmem_cache_flags(size, flags, name); 177 178 if (flags & SLAB_NEVER_MERGE) 179 return NULL; 180 181 list_for_each_entry_reverse(s, &slab_caches, list) { 182 if (slab_unmergeable(s)) 183 continue; 184 185 if (size > s->size) 186 continue; 187 188 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) 189 continue; 190 /* 191 * Check if alignment is compatible. 192 * Courtesy of Adrian Drzewiecki 193 */ 194 if ((s->size & ~(align - 1)) != s->size) 195 continue; 196 197 if (s->size - size >= sizeof(void *)) 198 continue; 199 200 if (IS_ENABLED(CONFIG_SLAB) && align && 201 (align > s->align || s->align % align)) 202 continue; 203 204 return s; 205 } 206 return NULL; 207 } 208 209 static struct kmem_cache *create_cache(const char *name, 210 unsigned int object_size, unsigned int align, 211 slab_flags_t flags, unsigned int useroffset, 212 unsigned int usersize, void (*ctor)(void *), 213 struct kmem_cache *root_cache) 214 { 215 struct kmem_cache *s; 216 int err; 217 218 if (WARN_ON(useroffset + usersize > object_size)) 219 useroffset = usersize = 0; 220 221 err = -ENOMEM; 222 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); 223 if (!s) 224 goto out; 225 226 s->name = name; 227 s->size = s->object_size = object_size; 228 s->align = align; 229 s->ctor = ctor; 230 #ifdef CONFIG_HARDENED_USERCOPY 231 s->useroffset = useroffset; 232 s->usersize = usersize; 233 #endif 234 235 err = __kmem_cache_create(s, flags); 236 if (err) 237 goto out_free_cache; 238 239 s->refcount = 1; 240 list_add(&s->list, &slab_caches); 241 return s; 242 243 out_free_cache: 244 kmem_cache_free(kmem_cache, s); 245 out: 246 return ERR_PTR(err); 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 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 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 if (flags & SLAB_DEBUG_FLAGS) 297 static_branch_enable(&slub_debug_enabled); 298 if (flags & SLAB_STORE_USER) 299 stack_depot_init(); 300 #endif 301 302 mutex_lock(&slab_mutex); 303 304 err = kmem_cache_sanity_check(name, size); 305 if (err) { 306 goto out_unlock; 307 } 308 309 /* Refuse requests with allocator specific flags */ 310 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 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 usersize = useroffset = 0; 328 329 if (!usersize) 330 s = __kmem_cache_alias(name, size, align, flags, ctor); 331 if (s) 332 goto out_unlock; 333 334 cache_name = kstrdup_const(name, GFP_KERNEL); 335 if (!cache_name) { 336 err = -ENOMEM; 337 goto out_unlock; 338 } 339 340 s = create_cache(cache_name, size, 341 calculate_alignment(flags, align, size), 342 flags, useroffset, usersize, ctor, NULL); 343 if (IS_ERR(s)) { 344 err = PTR_ERR(s); 345 kfree_const(cache_name); 346 } 347 348 out_unlock: 349 mutex_unlock(&slab_mutex); 350 351 if (err) { 352 if (flags & SLAB_PANIC) 353 panic("%s: Failed to create slab '%s'. Error %d\n", 354 __func__, name, err); 355 else { 356 pr_warn("%s(%s) failed with error %d\n", 357 __func__, name, err); 358 dump_stack(); 359 } 360 return NULL; 361 } 362 return s; 363 } 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 kmem_cache_create(const char *name, unsigned int size, unsigned int align, 393 slab_flags_t flags, void (*ctor)(void *)) 394 { 395 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 sysfs_slab_unlink(s); 413 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 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) 423 { 424 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 mutex_lock(&slab_mutex); 437 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy); 438 mutex_unlock(&slab_mutex); 439 440 if (list_empty(&to_destroy)) 441 return; 442 443 rcu_barrier(); 444 445 list_for_each_entry_safe(s, s2, &to_destroy, list) { 446 debugfs_slab_release(s); 447 kfence_shutdown_cache(s); 448 kmem_cache_release(s); 449 } 450 } 451 452 static int shutdown_cache(struct kmem_cache *s) 453 { 454 /* free asan quarantined objects */ 455 kasan_cache_shutdown(s); 456 457 if (__kmem_cache_shutdown(s) != 0) 458 return -EBUSY; 459 460 list_del(&s->list); 461 462 if (s->flags & SLAB_TYPESAFE_BY_RCU) { 463 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 void slab_kmem_cache_release(struct kmem_cache *s) 474 { 475 __kmem_cache_release(s); 476 kfree_const(s->name); 477 kmem_cache_free(kmem_cache, s); 478 } 479 480 void kmem_cache_destroy(struct kmem_cache *s) 481 { 482 int err = -EBUSY; 483 bool rcu_set; 484 485 if (unlikely(!s) || !kasan_check_byte(s)) 486 return; 487 488 cpus_read_lock(); 489 mutex_lock(&slab_mutex); 490 491 rcu_set = s->flags & SLAB_TYPESAFE_BY_RCU; 492 493 s->refcount--; 494 if (s->refcount) 495 goto out_unlock; 496 497 err = shutdown_cache(s); 498 WARN(err, "%s %s: Slab cache still has objects when called from %pS", 499 __func__, s->name, (void *)_RET_IP_); 500 out_unlock: 501 mutex_unlock(&slab_mutex); 502 cpus_read_unlock(); 503 if (!err && !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 int kmem_cache_shrink(struct kmem_cache *cachep) 518 { 519 kasan_cache_shrink(cachep); 520 521 return __kmem_cache_shrink(cachep); 522 } 523 EXPORT_SYMBOL(kmem_cache_shrink); 524 525 bool slab_is_available(void) 526 { 527 return slab_state >= UP; 528 } 529 530 #ifdef CONFIG_PRINTK 531 static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab) 532 { 533 if (__kfence_obj_info(kpp, object, slab)) 534 return; 535 __kmem_obj_info(kpp, object, slab); 536 } 537 538 /** 539 * kmem_dump_obj - Print available slab provenance information 540 * @object: slab object for which to find provenance information. 541 * 542 * This function uses pr_cont(), so that the caller is expected to have 543 * printed out whatever preamble is appropriate. The provenance information 544 * depends on the type of object and on how much debugging is enabled. 545 * For a slab-cache object, the fact that it is a slab object is printed, 546 * and, if available, the slab name, return address, and stack trace from 547 * the allocation and last free path of that object. 548 * 549 * Return: %true if the pointer is to a not-yet-freed object from 550 * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer 551 * is to an already-freed object, and %false otherwise. 552 */ 553 bool kmem_dump_obj(void *object) 554 { 555 char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc"; 556 int i; 557 struct slab *slab; 558 unsigned long ptroffset; 559 struct kmem_obj_info kp = { }; 560 561 /* Some arches consider ZERO_SIZE_PTR to be a valid address. */ 562 if (object < (void *)PAGE_SIZE || !virt_addr_valid(object)) 563 return false; 564 slab = virt_to_slab(object); 565 if (!slab) 566 return false; 567 568 kmem_obj_info(&kp, object, slab); 569 if (kp.kp_slab_cache) 570 pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name); 571 else 572 pr_cont(" slab%s", cp); 573 if (is_kfence_address(object)) 574 pr_cont(" (kfence)"); 575 if (kp.kp_objp) 576 pr_cont(" start %px", kp.kp_objp); 577 if (kp.kp_data_offset) 578 pr_cont(" data offset %lu", kp.kp_data_offset); 579 if (kp.kp_objp) { 580 ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset; 581 pr_cont(" pointer offset %lu", ptroffset); 582 } 583 if (kp.kp_slab_cache && kp.kp_slab_cache->object_size) 584 pr_cont(" size %u", kp.kp_slab_cache->object_size); 585 if (kp.kp_ret) 586 pr_cont(" allocated at %pS\n", kp.kp_ret); 587 else 588 pr_cont("\n"); 589 for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) { 590 if (!kp.kp_stack[i]) 591 break; 592 pr_info(" %pS\n", kp.kp_stack[i]); 593 } 594 595 if (kp.kp_free_stack[0]) 596 pr_cont(" Free path:\n"); 597 598 for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) { 599 if (!kp.kp_free_stack[i]) 600 break; 601 pr_info(" %pS\n", kp.kp_free_stack[i]); 602 } 603 604 return true; 605 } 606 EXPORT_SYMBOL_GPL(kmem_dump_obj); 607 #endif 608 609 /* Create a cache during boot when no slab services are available yet */ 610 void __init create_boot_cache(struct kmem_cache *s, const char *name, 611 unsigned int size, slab_flags_t flags, 612 unsigned int useroffset, unsigned int usersize) 613 { 614 int err; 615 unsigned int align = ARCH_KMALLOC_MINALIGN; 616 617 s->name = name; 618 s->size = s->object_size = size; 619 620 /* 621 * For power of two sizes, guarantee natural alignment for kmalloc 622 * caches, regardless of SL*B debugging options. 623 */ 624 if (is_power_of_2(size)) 625 align = max(align, size); 626 s->align = calculate_alignment(flags, align, size); 627 628 #ifdef CONFIG_HARDENED_USERCOPY 629 s->useroffset = useroffset; 630 s->usersize = usersize; 631 #endif 632 633 err = __kmem_cache_create(s, flags); 634 635 if (err) 636 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n", 637 name, size, err); 638 639 s->refcount = -1; /* Exempt from merging for now */ 640 } 641 642 static struct kmem_cache *__init create_kmalloc_cache(const char *name, 643 unsigned int size, 644 slab_flags_t flags) 645 { 646 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); 647 648 if (!s) 649 panic("Out of memory when creating slab %s\n", name); 650 651 create_boot_cache(s, name, size, flags | SLAB_KMALLOC, 0, size); 652 list_add(&s->list, &slab_caches); 653 s->refcount = 1; 654 return s; 655 } 656 657 struct kmem_cache * 658 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init = 659 { /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ }; 660 EXPORT_SYMBOL(kmalloc_caches); 661 662 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 663 unsigned long random_kmalloc_seed __ro_after_init; 664 EXPORT_SYMBOL(random_kmalloc_seed); 665 #endif 666 667 /* 668 * Conversion table for small slabs sizes / 8 to the index in the 669 * kmalloc array. This is necessary for slabs < 192 since we have non power 670 * of two cache sizes there. The size of larger slabs can be determined using 671 * fls. 672 */ 673 static u8 size_index[24] __ro_after_init = { 674 3, /* 8 */ 675 4, /* 16 */ 676 5, /* 24 */ 677 5, /* 32 */ 678 6, /* 40 */ 679 6, /* 48 */ 680 6, /* 56 */ 681 6, /* 64 */ 682 1, /* 72 */ 683 1, /* 80 */ 684 1, /* 88 */ 685 1, /* 96 */ 686 7, /* 104 */ 687 7, /* 112 */ 688 7, /* 120 */ 689 7, /* 128 */ 690 2, /* 136 */ 691 2, /* 144 */ 692 2, /* 152 */ 693 2, /* 160 */ 694 2, /* 168 */ 695 2, /* 176 */ 696 2, /* 184 */ 697 2 /* 192 */ 698 }; 699 700 static inline unsigned int size_index_elem(unsigned int bytes) 701 { 702 return (bytes - 1) / 8; 703 } 704 705 /* 706 * Find the kmem_cache structure that serves a given size of 707 * allocation 708 */ 709 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags, unsigned long caller) 710 { 711 unsigned int index; 712 713 if (size <= 192) { 714 if (!size) 715 return ZERO_SIZE_PTR; 716 717 index = size_index[size_index_elem(size)]; 718 } else { 719 if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE)) 720 return NULL; 721 index = fls(size - 1); 722 } 723 724 return kmalloc_caches[kmalloc_type(flags, caller)][index]; 725 } 726 727 size_t kmalloc_size_roundup(size_t size) 728 { 729 if (size && size <= KMALLOC_MAX_CACHE_SIZE) { 730 /* 731 * The flags don't matter since size_index is common to all. 732 * Neither does the caller for just getting ->object_size. 733 */ 734 return kmalloc_slab(size, GFP_KERNEL, 0)->object_size; 735 } 736 737 /* Above the smaller buckets, size is a multiple of page size. */ 738 if (size && size <= KMALLOC_MAX_SIZE) 739 return PAGE_SIZE << get_order(size); 740 741 /* 742 * Return 'size' for 0 - kmalloc() returns ZERO_SIZE_PTR 743 * and very large size - kmalloc() may fail. 744 */ 745 return size; 746 747 } 748 EXPORT_SYMBOL(kmalloc_size_roundup); 749 750 #ifdef CONFIG_ZONE_DMA 751 #define KMALLOC_DMA_NAME(sz) .name[KMALLOC_DMA] = "dma-kmalloc-" #sz, 752 #else 753 #define KMALLOC_DMA_NAME(sz) 754 #endif 755 756 #ifdef CONFIG_MEMCG_KMEM 757 #define KMALLOC_CGROUP_NAME(sz) .name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz, 758 #else 759 #define KMALLOC_CGROUP_NAME(sz) 760 #endif 761 762 #ifndef CONFIG_SLUB_TINY 763 #define KMALLOC_RCL_NAME(sz) .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #sz, 764 #else 765 #define KMALLOC_RCL_NAME(sz) 766 #endif 767 768 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 769 #define __KMALLOC_RANDOM_CONCAT(a, b) a ## b 770 #define KMALLOC_RANDOM_NAME(N, sz) __KMALLOC_RANDOM_CONCAT(KMA_RAND_, N)(sz) 771 #define KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 1] = "kmalloc-rnd-01-" #sz, 772 #define KMA_RAND_2(sz) KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 2] = "kmalloc-rnd-02-" #sz, 773 #define KMA_RAND_3(sz) KMA_RAND_2(sz) .name[KMALLOC_RANDOM_START + 3] = "kmalloc-rnd-03-" #sz, 774 #define KMA_RAND_4(sz) KMA_RAND_3(sz) .name[KMALLOC_RANDOM_START + 4] = "kmalloc-rnd-04-" #sz, 775 #define KMA_RAND_5(sz) KMA_RAND_4(sz) .name[KMALLOC_RANDOM_START + 5] = "kmalloc-rnd-05-" #sz, 776 #define KMA_RAND_6(sz) KMA_RAND_5(sz) .name[KMALLOC_RANDOM_START + 6] = "kmalloc-rnd-06-" #sz, 777 #define KMA_RAND_7(sz) KMA_RAND_6(sz) .name[KMALLOC_RANDOM_START + 7] = "kmalloc-rnd-07-" #sz, 778 #define KMA_RAND_8(sz) KMA_RAND_7(sz) .name[KMALLOC_RANDOM_START + 8] = "kmalloc-rnd-08-" #sz, 779 #define KMA_RAND_9(sz) KMA_RAND_8(sz) .name[KMALLOC_RANDOM_START + 9] = "kmalloc-rnd-09-" #sz, 780 #define KMA_RAND_10(sz) KMA_RAND_9(sz) .name[KMALLOC_RANDOM_START + 10] = "kmalloc-rnd-10-" #sz, 781 #define KMA_RAND_11(sz) KMA_RAND_10(sz) .name[KMALLOC_RANDOM_START + 11] = "kmalloc-rnd-11-" #sz, 782 #define KMA_RAND_12(sz) KMA_RAND_11(sz) .name[KMALLOC_RANDOM_START + 12] = "kmalloc-rnd-12-" #sz, 783 #define KMA_RAND_13(sz) KMA_RAND_12(sz) .name[KMALLOC_RANDOM_START + 13] = "kmalloc-rnd-13-" #sz, 784 #define KMA_RAND_14(sz) KMA_RAND_13(sz) .name[KMALLOC_RANDOM_START + 14] = "kmalloc-rnd-14-" #sz, 785 #define KMA_RAND_15(sz) KMA_RAND_14(sz) .name[KMALLOC_RANDOM_START + 15] = "kmalloc-rnd-15-" #sz, 786 #else // CONFIG_RANDOM_KMALLOC_CACHES 787 #define KMALLOC_RANDOM_NAME(N, sz) 788 #endif 789 790 #define INIT_KMALLOC_INFO(__size, __short_size) \ 791 { \ 792 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \ 793 KMALLOC_RCL_NAME(__short_size) \ 794 KMALLOC_CGROUP_NAME(__short_size) \ 795 KMALLOC_DMA_NAME(__short_size) \ 796 KMALLOC_RANDOM_NAME(RANDOM_KMALLOC_CACHES_NR, __short_size) \ 797 .size = __size, \ 798 } 799 800 /* 801 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. 802 * kmalloc_index() supports up to 2^21=2MB, so the final entry of the table is 803 * kmalloc-2M. 804 */ 805 const struct kmalloc_info_struct kmalloc_info[] __initconst = { 806 INIT_KMALLOC_INFO(0, 0), 807 INIT_KMALLOC_INFO(96, 96), 808 INIT_KMALLOC_INFO(192, 192), 809 INIT_KMALLOC_INFO(8, 8), 810 INIT_KMALLOC_INFO(16, 16), 811 INIT_KMALLOC_INFO(32, 32), 812 INIT_KMALLOC_INFO(64, 64), 813 INIT_KMALLOC_INFO(128, 128), 814 INIT_KMALLOC_INFO(256, 256), 815 INIT_KMALLOC_INFO(512, 512), 816 INIT_KMALLOC_INFO(1024, 1k), 817 INIT_KMALLOC_INFO(2048, 2k), 818 INIT_KMALLOC_INFO(4096, 4k), 819 INIT_KMALLOC_INFO(8192, 8k), 820 INIT_KMALLOC_INFO(16384, 16k), 821 INIT_KMALLOC_INFO(32768, 32k), 822 INIT_KMALLOC_INFO(65536, 64k), 823 INIT_KMALLOC_INFO(131072, 128k), 824 INIT_KMALLOC_INFO(262144, 256k), 825 INIT_KMALLOC_INFO(524288, 512k), 826 INIT_KMALLOC_INFO(1048576, 1M), 827 INIT_KMALLOC_INFO(2097152, 2M) 828 }; 829 830 /* 831 * Patch up the size_index table if we have strange large alignment 832 * requirements for the kmalloc array. This is only the case for 833 * MIPS it seems. The standard arches will not generate any code here. 834 * 835 * Largest permitted alignment is 256 bytes due to the way we 836 * handle the index determination for the smaller caches. 837 * 838 * Make sure that nothing crazy happens if someone starts tinkering 839 * around with ARCH_KMALLOC_MINALIGN 840 */ 841 void __init setup_kmalloc_cache_index_table(void) 842 { 843 unsigned int i; 844 845 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || 846 !is_power_of_2(KMALLOC_MIN_SIZE)); 847 848 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { 849 unsigned int elem = size_index_elem(i); 850 851 if (elem >= ARRAY_SIZE(size_index)) 852 break; 853 size_index[elem] = KMALLOC_SHIFT_LOW; 854 } 855 856 if (KMALLOC_MIN_SIZE >= 64) { 857 /* 858 * The 96 byte sized cache is not used if the alignment 859 * is 64 byte. 860 */ 861 for (i = 64 + 8; i <= 96; i += 8) 862 size_index[size_index_elem(i)] = 7; 863 864 } 865 866 if (KMALLOC_MIN_SIZE >= 128) { 867 /* 868 * The 192 byte sized cache is not used if the alignment 869 * is 128 byte. Redirect kmalloc to use the 256 byte cache 870 * instead. 871 */ 872 for (i = 128 + 8; i <= 192; i += 8) 873 size_index[size_index_elem(i)] = 8; 874 } 875 } 876 877 static unsigned int __kmalloc_minalign(void) 878 { 879 unsigned int minalign = dma_get_cache_alignment(); 880 881 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && 882 is_swiotlb_allocated()) 883 minalign = ARCH_KMALLOC_MINALIGN; 884 885 return max(minalign, arch_slab_minalign()); 886 } 887 888 void __init 889 new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) 890 { 891 unsigned int minalign = __kmalloc_minalign(); 892 unsigned int aligned_size = kmalloc_info[idx].size; 893 int aligned_idx = idx; 894 895 if ((KMALLOC_RECLAIM != KMALLOC_NORMAL) && (type == KMALLOC_RECLAIM)) { 896 flags |= SLAB_RECLAIM_ACCOUNT; 897 } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) { 898 if (mem_cgroup_kmem_disabled()) { 899 kmalloc_caches[type][idx] = kmalloc_caches[KMALLOC_NORMAL][idx]; 900 return; 901 } 902 flags |= SLAB_ACCOUNT; 903 } else if (IS_ENABLED(CONFIG_ZONE_DMA) && (type == KMALLOC_DMA)) { 904 flags |= SLAB_CACHE_DMA; 905 } 906 907 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 908 if (type >= KMALLOC_RANDOM_START && type <= KMALLOC_RANDOM_END) 909 flags |= SLAB_NO_MERGE; 910 #endif 911 912 /* 913 * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for 914 * KMALLOC_NORMAL caches. 915 */ 916 if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_NORMAL)) 917 flags |= SLAB_NO_MERGE; 918 919 if (minalign > ARCH_KMALLOC_MINALIGN) { 920 aligned_size = ALIGN(aligned_size, minalign); 921 aligned_idx = __kmalloc_index(aligned_size, false); 922 } 923 924 if (!kmalloc_caches[type][aligned_idx]) 925 kmalloc_caches[type][aligned_idx] = create_kmalloc_cache( 926 kmalloc_info[aligned_idx].name[type], 927 aligned_size, flags); 928 if (idx != aligned_idx) 929 kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx]; 930 } 931 932 /* 933 * Create the kmalloc array. Some of the regular kmalloc arrays 934 * may already have been created because they were needed to 935 * enable allocations for slab creation. 936 */ 937 void __init create_kmalloc_caches(slab_flags_t flags) 938 { 939 int i; 940 enum kmalloc_cache_type type; 941 942 /* 943 * Including KMALLOC_CGROUP if CONFIG_MEMCG_KMEM defined 944 */ 945 for (type = KMALLOC_NORMAL; type < NR_KMALLOC_TYPES; type++) { 946 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { 947 if (!kmalloc_caches[type][i]) 948 new_kmalloc_cache(i, type, flags); 949 950 /* 951 * Caches that are not of the two-to-the-power-of size. 952 * These have to be created immediately after the 953 * earlier power of two caches 954 */ 955 if (KMALLOC_MIN_SIZE <= 32 && i == 6 && 956 !kmalloc_caches[type][1]) 957 new_kmalloc_cache(1, type, flags); 958 if (KMALLOC_MIN_SIZE <= 64 && i == 7 && 959 !kmalloc_caches[type][2]) 960 new_kmalloc_cache(2, type, flags); 961 } 962 } 963 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 964 random_kmalloc_seed = get_random_u64(); 965 #endif 966 967 /* Kmalloc array is now usable */ 968 slab_state = UP; 969 } 970 971 void free_large_kmalloc(struct folio *folio, void *object) 972 { 973 unsigned int order = folio_order(folio); 974 975 if (WARN_ON_ONCE(order == 0)) 976 pr_warn_once("object pointer: 0x%p\n", object); 977 978 kmemleak_free(object); 979 kasan_kfree_large(object); 980 kmsan_kfree_large(object); 981 982 mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B, 983 -(PAGE_SIZE << order)); 984 __free_pages(folio_page(folio, 0), order); 985 } 986 987 static void *__kmalloc_large_node(size_t size, gfp_t flags, int node); 988 static __always_inline 989 void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller) 990 { 991 struct kmem_cache *s; 992 void *ret; 993 994 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) { 995 ret = __kmalloc_large_node(size, flags, node); 996 trace_kmalloc(caller, ret, size, 997 PAGE_SIZE << get_order(size), flags, node); 998 return ret; 999 } 1000 1001 s = kmalloc_slab(size, flags, caller); 1002 1003 if (unlikely(ZERO_OR_NULL_PTR(s))) 1004 return s; 1005 1006 ret = __kmem_cache_alloc_node(s, flags, node, size, caller); 1007 ret = kasan_kmalloc(s, ret, size, flags); 1008 trace_kmalloc(caller, ret, size, s->size, flags, node); 1009 return ret; 1010 } 1011 1012 void *__kmalloc_node(size_t size, gfp_t flags, int node) 1013 { 1014 return __do_kmalloc_node(size, flags, node, _RET_IP_); 1015 } 1016 EXPORT_SYMBOL(__kmalloc_node); 1017 1018 void *__kmalloc(size_t size, gfp_t flags) 1019 { 1020 return __do_kmalloc_node(size, flags, NUMA_NO_NODE, _RET_IP_); 1021 } 1022 EXPORT_SYMBOL(__kmalloc); 1023 1024 void *__kmalloc_node_track_caller(size_t size, gfp_t flags, 1025 int node, unsigned long caller) 1026 { 1027 return __do_kmalloc_node(size, flags, node, caller); 1028 } 1029 EXPORT_SYMBOL(__kmalloc_node_track_caller); 1030 1031 /** 1032 * kfree - free previously allocated memory 1033 * @object: pointer returned by kmalloc() or kmem_cache_alloc() 1034 * 1035 * If @object is NULL, no operation is performed. 1036 */ 1037 void kfree(const void *object) 1038 { 1039 struct folio *folio; 1040 struct slab *slab; 1041 struct kmem_cache *s; 1042 1043 trace_kfree(_RET_IP_, object); 1044 1045 if (unlikely(ZERO_OR_NULL_PTR(object))) 1046 return; 1047 1048 folio = virt_to_folio(object); 1049 if (unlikely(!folio_test_slab(folio))) { 1050 free_large_kmalloc(folio, (void *)object); 1051 return; 1052 } 1053 1054 slab = folio_slab(folio); 1055 s = slab->slab_cache; 1056 __kmem_cache_free(s, (void *)object, _RET_IP_); 1057 } 1058 EXPORT_SYMBOL(kfree); 1059 1060 /** 1061 * __ksize -- Report full size of underlying allocation 1062 * @object: pointer to the object 1063 * 1064 * This should only be used internally to query the true size of allocations. 1065 * It is not meant to be a way to discover the usable size of an allocation 1066 * after the fact. Instead, use kmalloc_size_roundup(). Using memory beyond 1067 * the originally requested allocation size may trigger KASAN, UBSAN_BOUNDS, 1068 * and/or FORTIFY_SOURCE. 1069 * 1070 * Return: size of the actual memory used by @object in bytes 1071 */ 1072 size_t __ksize(const void *object) 1073 { 1074 struct folio *folio; 1075 1076 if (unlikely(object == ZERO_SIZE_PTR)) 1077 return 0; 1078 1079 folio = virt_to_folio(object); 1080 1081 if (unlikely(!folio_test_slab(folio))) { 1082 if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE)) 1083 return 0; 1084 if (WARN_ON(object != folio_address(folio))) 1085 return 0; 1086 return folio_size(folio); 1087 } 1088 1089 #ifdef CONFIG_SLUB_DEBUG 1090 skip_orig_size_check(folio_slab(folio)->slab_cache, object); 1091 #endif 1092 1093 return slab_ksize(folio_slab(folio)->slab_cache); 1094 } 1095 1096 void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size) 1097 { 1098 void *ret = __kmem_cache_alloc_node(s, gfpflags, NUMA_NO_NODE, 1099 size, _RET_IP_); 1100 1101 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE); 1102 1103 ret = kasan_kmalloc(s, ret, size, gfpflags); 1104 return ret; 1105 } 1106 EXPORT_SYMBOL(kmalloc_trace); 1107 1108 void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags, 1109 int node, size_t size) 1110 { 1111 void *ret = __kmem_cache_alloc_node(s, gfpflags, node, size, _RET_IP_); 1112 1113 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node); 1114 1115 ret = kasan_kmalloc(s, ret, size, gfpflags); 1116 return ret; 1117 } 1118 EXPORT_SYMBOL(kmalloc_node_trace); 1119 1120 gfp_t kmalloc_fix_flags(gfp_t flags) 1121 { 1122 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK; 1123 1124 flags &= ~GFP_SLAB_BUG_MASK; 1125 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n", 1126 invalid_mask, &invalid_mask, flags, &flags); 1127 dump_stack(); 1128 1129 return flags; 1130 } 1131 1132 /* 1133 * To avoid unnecessary overhead, we pass through large allocation requests 1134 * directly to the page allocator. We use __GFP_COMP, because we will need to 1135 * know the allocation order to free the pages properly in kfree. 1136 */ 1137 1138 static void *__kmalloc_large_node(size_t size, gfp_t flags, int node) 1139 { 1140 struct page *page; 1141 void *ptr = NULL; 1142 unsigned int order = get_order(size); 1143 1144 if (unlikely(flags & GFP_SLAB_BUG_MASK)) 1145 flags = kmalloc_fix_flags(flags); 1146 1147 flags |= __GFP_COMP; 1148 page = alloc_pages_node(node, flags, order); 1149 if (page) { 1150 ptr = page_address(page); 1151 mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, 1152 PAGE_SIZE << order); 1153 } 1154 1155 ptr = kasan_kmalloc_large(ptr, size, flags); 1156 /* As ptr might get tagged, call kmemleak hook after KASAN. */ 1157 kmemleak_alloc(ptr, size, 1, flags); 1158 kmsan_kmalloc_large(ptr, size, flags); 1159 1160 return ptr; 1161 } 1162 1163 void *kmalloc_large(size_t size, gfp_t flags) 1164 { 1165 void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE); 1166 1167 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size), 1168 flags, NUMA_NO_NODE); 1169 return ret; 1170 } 1171 EXPORT_SYMBOL(kmalloc_large); 1172 1173 void *kmalloc_large_node(size_t size, gfp_t flags, int node) 1174 { 1175 void *ret = __kmalloc_large_node(size, flags, node); 1176 1177 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size), 1178 flags, node); 1179 return ret; 1180 } 1181 EXPORT_SYMBOL(kmalloc_large_node); 1182 1183 #ifdef CONFIG_SLAB_FREELIST_RANDOM 1184 /* Randomize a generic freelist */ 1185 static void freelist_randomize(unsigned int *list, 1186 unsigned int count) 1187 { 1188 unsigned int rand; 1189 unsigned int i; 1190 1191 for (i = 0; i < count; i++) 1192 list[i] = i; 1193 1194 /* Fisher-Yates shuffle */ 1195 for (i = count - 1; i > 0; i--) { 1196 rand = get_random_u32_below(i + 1); 1197 swap(list[i], list[rand]); 1198 } 1199 } 1200 1201 /* Create a random sequence per cache */ 1202 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, 1203 gfp_t gfp) 1204 { 1205 1206 if (count < 2 || cachep->random_seq) 1207 return 0; 1208 1209 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp); 1210 if (!cachep->random_seq) 1211 return -ENOMEM; 1212 1213 freelist_randomize(cachep->random_seq, count); 1214 return 0; 1215 } 1216 1217 /* Destroy the per-cache random freelist sequence */ 1218 void cache_random_seq_destroy(struct kmem_cache *cachep) 1219 { 1220 kfree(cachep->random_seq); 1221 cachep->random_seq = NULL; 1222 } 1223 #endif /* CONFIG_SLAB_FREELIST_RANDOM */ 1224 1225 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) 1226 #ifdef CONFIG_SLAB 1227 #define SLABINFO_RIGHTS (0600) 1228 #else 1229 #define SLABINFO_RIGHTS (0400) 1230 #endif 1231 1232 static void print_slabinfo_header(struct seq_file *m) 1233 { 1234 /* 1235 * Output format version, so at least we can change it 1236 * without _too_ many complaints. 1237 */ 1238 #ifdef CONFIG_DEBUG_SLAB 1239 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 1240 #else 1241 seq_puts(m, "slabinfo - version: 2.1\n"); 1242 #endif 1243 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>"); 1244 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 1245 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 1246 #ifdef CONFIG_DEBUG_SLAB 1247 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 1248 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 1249 #endif 1250 seq_putc(m, '\n'); 1251 } 1252 1253 static void *slab_start(struct seq_file *m, loff_t *pos) 1254 { 1255 mutex_lock(&slab_mutex); 1256 return seq_list_start(&slab_caches, *pos); 1257 } 1258 1259 static void *slab_next(struct seq_file *m, void *p, loff_t *pos) 1260 { 1261 return seq_list_next(p, &slab_caches, pos); 1262 } 1263 1264 static void slab_stop(struct seq_file *m, void *p) 1265 { 1266 mutex_unlock(&slab_mutex); 1267 } 1268 1269 static void cache_show(struct kmem_cache *s, struct seq_file *m) 1270 { 1271 struct slabinfo sinfo; 1272 1273 memset(&sinfo, 0, sizeof(sinfo)); 1274 get_slabinfo(s, &sinfo); 1275 1276 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 1277 s->name, sinfo.active_objs, sinfo.num_objs, s->size, 1278 sinfo.objects_per_slab, (1 << sinfo.cache_order)); 1279 1280 seq_printf(m, " : tunables %4u %4u %4u", 1281 sinfo.limit, sinfo.batchcount, sinfo.shared); 1282 seq_printf(m, " : slabdata %6lu %6lu %6lu", 1283 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); 1284 slabinfo_show_stats(m, s); 1285 seq_putc(m, '\n'); 1286 } 1287 1288 static int slab_show(struct seq_file *m, void *p) 1289 { 1290 struct kmem_cache *s = list_entry(p, struct kmem_cache, list); 1291 1292 if (p == slab_caches.next) 1293 print_slabinfo_header(m); 1294 cache_show(s, m); 1295 return 0; 1296 } 1297 1298 void dump_unreclaimable_slab(void) 1299 { 1300 struct kmem_cache *s; 1301 struct slabinfo sinfo; 1302 1303 /* 1304 * Here acquiring slab_mutex is risky since we don't prefer to get 1305 * sleep in oom path. But, without mutex hold, it may introduce a 1306 * risk of crash. 1307 * Use mutex_trylock to protect the list traverse, dump nothing 1308 * without acquiring the mutex. 1309 */ 1310 if (!mutex_trylock(&slab_mutex)) { 1311 pr_warn("excessive unreclaimable slab but cannot dump stats\n"); 1312 return; 1313 } 1314 1315 pr_info("Unreclaimable slab info:\n"); 1316 pr_info("Name Used Total\n"); 1317 1318 list_for_each_entry(s, &slab_caches, list) { 1319 if (s->flags & SLAB_RECLAIM_ACCOUNT) 1320 continue; 1321 1322 get_slabinfo(s, &sinfo); 1323 1324 if (sinfo.num_objs > 0) 1325 pr_info("%-17s %10luKB %10luKB\n", s->name, 1326 (sinfo.active_objs * s->size) / 1024, 1327 (sinfo.num_objs * s->size) / 1024); 1328 } 1329 mutex_unlock(&slab_mutex); 1330 } 1331 1332 /* 1333 * slabinfo_op - iterator that generates /proc/slabinfo 1334 * 1335 * Output layout: 1336 * cache-name 1337 * num-active-objs 1338 * total-objs 1339 * object size 1340 * num-active-slabs 1341 * total-slabs 1342 * num-pages-per-slab 1343 * + further values on SMP and with statistics enabled 1344 */ 1345 static const struct seq_operations slabinfo_op = { 1346 .start = slab_start, 1347 .next = slab_next, 1348 .stop = slab_stop, 1349 .show = slab_show, 1350 }; 1351 1352 static int slabinfo_open(struct inode *inode, struct file *file) 1353 { 1354 return seq_open(file, &slabinfo_op); 1355 } 1356 1357 static const struct proc_ops slabinfo_proc_ops = { 1358 .proc_flags = PROC_ENTRY_PERMANENT, 1359 .proc_open = slabinfo_open, 1360 .proc_read = seq_read, 1361 .proc_write = slabinfo_write, 1362 .proc_lseek = seq_lseek, 1363 .proc_release = seq_release, 1364 }; 1365 1366 static int __init slab_proc_init(void) 1367 { 1368 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops); 1369 return 0; 1370 } 1371 module_init(slab_proc_init); 1372 1373 #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */ 1374 1375 static __always_inline __realloc_size(2) void * 1376 __do_krealloc(const void *p, size_t new_size, gfp_t flags) 1377 { 1378 void *ret; 1379 size_t ks; 1380 1381 /* Check for double-free before calling ksize. */ 1382 if (likely(!ZERO_OR_NULL_PTR(p))) { 1383 if (!kasan_check_byte(p)) 1384 return NULL; 1385 ks = ksize(p); 1386 } else 1387 ks = 0; 1388 1389 /* If the object still fits, repoison it precisely. */ 1390 if (ks >= new_size) { 1391 p = kasan_krealloc((void *)p, new_size, flags); 1392 return (void *)p; 1393 } 1394 1395 ret = kmalloc_track_caller(new_size, flags); 1396 if (ret && p) { 1397 /* Disable KASAN checks as the object's redzone is accessed. */ 1398 kasan_disable_current(); 1399 memcpy(ret, kasan_reset_tag(p), ks); 1400 kasan_enable_current(); 1401 } 1402 1403 return ret; 1404 } 1405 1406 /** 1407 * krealloc - reallocate memory. The contents will remain unchanged. 1408 * @p: object to reallocate memory for. 1409 * @new_size: how many bytes of memory are required. 1410 * @flags: the type of memory to allocate. 1411 * 1412 * The contents of the object pointed to are preserved up to the 1413 * lesser of the new and old sizes (__GFP_ZERO flag is effectively ignored). 1414 * If @p is %NULL, krealloc() behaves exactly like kmalloc(). If @new_size 1415 * is 0 and @p is not a %NULL pointer, the object pointed to is freed. 1416 * 1417 * Return: pointer to the allocated memory or %NULL in case of error 1418 */ 1419 void *krealloc(const void *p, size_t new_size, gfp_t flags) 1420 { 1421 void *ret; 1422 1423 if (unlikely(!new_size)) { 1424 kfree(p); 1425 return ZERO_SIZE_PTR; 1426 } 1427 1428 ret = __do_krealloc(p, new_size, flags); 1429 if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret)) 1430 kfree(p); 1431 1432 return ret; 1433 } 1434 EXPORT_SYMBOL(krealloc); 1435 1436 /** 1437 * kfree_sensitive - Clear sensitive information in memory before freeing 1438 * @p: object to free memory of 1439 * 1440 * The memory of the object @p points to is zeroed before freed. 1441 * If @p is %NULL, kfree_sensitive() does nothing. 1442 * 1443 * Note: this function zeroes the whole allocated buffer which can be a good 1444 * deal bigger than the requested buffer size passed to kmalloc(). So be 1445 * careful when using this function in performance sensitive code. 1446 */ 1447 void kfree_sensitive(const void *p) 1448 { 1449 size_t ks; 1450 void *mem = (void *)p; 1451 1452 ks = ksize(mem); 1453 if (ks) { 1454 kasan_unpoison_range(mem, ks); 1455 memzero_explicit(mem, ks); 1456 } 1457 kfree(mem); 1458 } 1459 EXPORT_SYMBOL(kfree_sensitive); 1460 1461 size_t ksize(const void *objp) 1462 { 1463 /* 1464 * We need to first check that the pointer to the object is valid. 1465 * The KASAN report printed from ksize() is more useful, then when 1466 * it's printed later when the behaviour could be undefined due to 1467 * a potential use-after-free or double-free. 1468 * 1469 * We use kasan_check_byte(), which is supported for the hardware 1470 * tag-based KASAN mode, unlike kasan_check_read/write(). 1471 * 1472 * If the pointed to memory is invalid, we return 0 to avoid users of 1473 * ksize() writing to and potentially corrupting the memory region. 1474 * 1475 * We want to perform the check before __ksize(), to avoid potentially 1476 * crashing in __ksize() due to accessing invalid metadata. 1477 */ 1478 if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp)) 1479 return 0; 1480 1481 return kfence_ksize(objp) ?: __ksize(objp); 1482 } 1483 EXPORT_SYMBOL(ksize); 1484 1485 /* Tracepoints definitions. */ 1486 EXPORT_TRACEPOINT_SYMBOL(kmalloc); 1487 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); 1488 EXPORT_TRACEPOINT_SYMBOL(kfree); 1489 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); 1490 1491 int should_failslab(struct kmem_cache *s, gfp_t gfpflags) 1492 { 1493 if (__should_failslab(s, gfpflags)) 1494 return -ENOMEM; 1495 return 0; 1496 } 1497 ALLOW_ERROR_INJECTION(should_failslab, ERRNO); 1498