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 refcnt; 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 refcnt = --s->refcount; 494 if (refcnt) 495 goto out_unlock; 496 497 WARN(shutdown_cache(s), 498 "%s %s: Slab cache still has objects when called from %pS", 499 __func__, s->name, (void *)_RET_IP_); 500 out_unlock: 501 mutex_unlock(&slab_mutex); 502 cpus_read_unlock(); 503 if (!refcnt && !rcu_set) 504 kmem_cache_release(s); 505 } 506 EXPORT_SYMBOL(kmem_cache_destroy); 507 508 /** 509 * kmem_cache_shrink - Shrink a cache. 510 * @cachep: The cache to shrink. 511 * 512 * Releases as many slabs as possible for a cache. 513 * To help debugging, a zero exit status indicates all slabs were released. 514 * 515 * Return: %0 if all slabs were released, non-zero otherwise 516 */ 517 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 /** 532 * kmem_valid_obj - does the pointer reference a valid slab object? 533 * @object: pointer to query. 534 * 535 * Return: %true if the pointer is to a not-yet-freed object from 536 * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer 537 * is to an already-freed object, and %false otherwise. 538 */ 539 bool kmem_valid_obj(void *object) 540 { 541 struct folio *folio; 542 543 /* Some arches consider ZERO_SIZE_PTR to be a valid address. */ 544 if (object < (void *)PAGE_SIZE || !virt_addr_valid(object)) 545 return false; 546 folio = virt_to_folio(object); 547 return folio_test_slab(folio); 548 } 549 EXPORT_SYMBOL_GPL(kmem_valid_obj); 550 551 static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab) 552 { 553 if (__kfence_obj_info(kpp, object, slab)) 554 return; 555 __kmem_obj_info(kpp, object, slab); 556 } 557 558 /** 559 * kmem_dump_obj - Print available slab provenance information 560 * @object: slab object for which to find provenance information. 561 * 562 * This function uses pr_cont(), so that the caller is expected to have 563 * printed out whatever preamble is appropriate. The provenance information 564 * depends on the type of object and on how much debugging is enabled. 565 * For a slab-cache object, the fact that it is a slab object is printed, 566 * and, if available, the slab name, return address, and stack trace from 567 * the allocation and last free path of that object. 568 * 569 * This function will splat if passed a pointer to a non-slab object. 570 * If you are not sure what type of object you have, you should instead 571 * use mem_dump_obj(). 572 */ 573 void 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 (is_kfence_address(object)) 594 pr_cont(" (kfence)"); 595 if (kp.kp_objp) 596 pr_cont(" start %px", kp.kp_objp); 597 if (kp.kp_data_offset) 598 pr_cont(" data offset %lu", kp.kp_data_offset); 599 if (kp.kp_objp) { 600 ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset; 601 pr_cont(" pointer offset %lu", ptroffset); 602 } 603 if (kp.kp_slab_cache && kp.kp_slab_cache->object_size) 604 pr_cont(" size %u", kp.kp_slab_cache->object_size); 605 if (kp.kp_ret) 606 pr_cont(" allocated at %pS\n", kp.kp_ret); 607 else 608 pr_cont("\n"); 609 for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) { 610 if (!kp.kp_stack[i]) 611 break; 612 pr_info(" %pS\n", kp.kp_stack[i]); 613 } 614 615 if (kp.kp_free_stack[0]) 616 pr_cont(" Free path:\n"); 617 618 for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) { 619 if (!kp.kp_free_stack[i]) 620 break; 621 pr_info(" %pS\n", kp.kp_free_stack[i]); 622 } 623 624 } 625 EXPORT_SYMBOL_GPL(kmem_dump_obj); 626 #endif 627 628 /* Create a cache during boot when no slab services are available yet */ 629 void __init create_boot_cache(struct kmem_cache *s, const char *name, 630 unsigned int size, slab_flags_t flags, 631 unsigned int useroffset, unsigned int usersize) 632 { 633 int err; 634 unsigned int align = ARCH_KMALLOC_MINALIGN; 635 636 s->name = name; 637 s->size = s->object_size = size; 638 639 /* 640 * For power of two sizes, guarantee natural alignment for kmalloc 641 * caches, regardless of SL*B debugging options. 642 */ 643 if (is_power_of_2(size)) 644 align = max(align, size); 645 s->align = calculate_alignment(flags, align, size); 646 647 #ifdef CONFIG_HARDENED_USERCOPY 648 s->useroffset = useroffset; 649 s->usersize = usersize; 650 #endif 651 652 err = __kmem_cache_create(s, flags); 653 654 if (err) 655 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n", 656 name, size, err); 657 658 s->refcount = -1; /* Exempt from merging for now */ 659 } 660 661 static struct kmem_cache *__init create_kmalloc_cache(const char *name, 662 unsigned int size, 663 slab_flags_t flags) 664 { 665 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); 666 667 if (!s) 668 panic("Out of memory when creating slab %s\n", name); 669 670 create_boot_cache(s, name, size, flags | SLAB_KMALLOC, 0, size); 671 list_add(&s->list, &slab_caches); 672 s->refcount = 1; 673 return s; 674 } 675 676 struct kmem_cache * 677 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init = 678 { /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ }; 679 EXPORT_SYMBOL(kmalloc_caches); 680 681 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 682 unsigned long random_kmalloc_seed __ro_after_init; 683 EXPORT_SYMBOL(random_kmalloc_seed); 684 #endif 685 686 /* 687 * Conversion table for small slabs sizes / 8 to the index in the 688 * kmalloc array. This is necessary for slabs < 192 since we have non power 689 * of two cache sizes there. The size of larger slabs can be determined using 690 * fls. 691 */ 692 static u8 size_index[24] __ro_after_init = { 693 3, /* 8 */ 694 4, /* 16 */ 695 5, /* 24 */ 696 5, /* 32 */ 697 6, /* 40 */ 698 6, /* 48 */ 699 6, /* 56 */ 700 6, /* 64 */ 701 1, /* 72 */ 702 1, /* 80 */ 703 1, /* 88 */ 704 1, /* 96 */ 705 7, /* 104 */ 706 7, /* 112 */ 707 7, /* 120 */ 708 7, /* 128 */ 709 2, /* 136 */ 710 2, /* 144 */ 711 2, /* 152 */ 712 2, /* 160 */ 713 2, /* 168 */ 714 2, /* 176 */ 715 2, /* 184 */ 716 2 /* 192 */ 717 }; 718 719 static inline unsigned int size_index_elem(unsigned int bytes) 720 { 721 return (bytes - 1) / 8; 722 } 723 724 /* 725 * Find the kmem_cache structure that serves a given size of 726 * allocation 727 */ 728 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags, unsigned long caller) 729 { 730 unsigned int index; 731 732 if (size <= 192) { 733 if (!size) 734 return ZERO_SIZE_PTR; 735 736 index = size_index[size_index_elem(size)]; 737 } else { 738 if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE)) 739 return NULL; 740 index = fls(size - 1); 741 } 742 743 return kmalloc_caches[kmalloc_type(flags, caller)][index]; 744 } 745 746 size_t kmalloc_size_roundup(size_t size) 747 { 748 struct kmem_cache *c; 749 750 /* Short-circuit the 0 size case. */ 751 if (unlikely(size == 0)) 752 return 0; 753 /* Short-circuit saturated "too-large" case. */ 754 if (unlikely(size == SIZE_MAX)) 755 return SIZE_MAX; 756 /* Above the smaller buckets, size is a multiple of page size. */ 757 if (size > KMALLOC_MAX_CACHE_SIZE) 758 return PAGE_SIZE << get_order(size); 759 760 /* 761 * The flags don't matter since size_index is common to all. 762 * Neither does the caller for just getting ->object_size. 763 */ 764 c = kmalloc_slab(size, GFP_KERNEL, 0); 765 return c ? c->object_size : 0; 766 } 767 EXPORT_SYMBOL(kmalloc_size_roundup); 768 769 #ifdef CONFIG_ZONE_DMA 770 #define KMALLOC_DMA_NAME(sz) .name[KMALLOC_DMA] = "dma-kmalloc-" #sz, 771 #else 772 #define KMALLOC_DMA_NAME(sz) 773 #endif 774 775 #ifdef CONFIG_MEMCG_KMEM 776 #define KMALLOC_CGROUP_NAME(sz) .name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz, 777 #else 778 #define KMALLOC_CGROUP_NAME(sz) 779 #endif 780 781 #ifndef CONFIG_SLUB_TINY 782 #define KMALLOC_RCL_NAME(sz) .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #sz, 783 #else 784 #define KMALLOC_RCL_NAME(sz) 785 #endif 786 787 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 788 #define __KMALLOC_RANDOM_CONCAT(a, b) a ## b 789 #define KMALLOC_RANDOM_NAME(N, sz) __KMALLOC_RANDOM_CONCAT(KMA_RAND_, N)(sz) 790 #define KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 1] = "kmalloc-rnd-01-" #sz, 791 #define KMA_RAND_2(sz) KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 2] = "kmalloc-rnd-02-" #sz, 792 #define KMA_RAND_3(sz) KMA_RAND_2(sz) .name[KMALLOC_RANDOM_START + 3] = "kmalloc-rnd-03-" #sz, 793 #define KMA_RAND_4(sz) KMA_RAND_3(sz) .name[KMALLOC_RANDOM_START + 4] = "kmalloc-rnd-04-" #sz, 794 #define KMA_RAND_5(sz) KMA_RAND_4(sz) .name[KMALLOC_RANDOM_START + 5] = "kmalloc-rnd-05-" #sz, 795 #define KMA_RAND_6(sz) KMA_RAND_5(sz) .name[KMALLOC_RANDOM_START + 6] = "kmalloc-rnd-06-" #sz, 796 #define KMA_RAND_7(sz) KMA_RAND_6(sz) .name[KMALLOC_RANDOM_START + 7] = "kmalloc-rnd-07-" #sz, 797 #define KMA_RAND_8(sz) KMA_RAND_7(sz) .name[KMALLOC_RANDOM_START + 8] = "kmalloc-rnd-08-" #sz, 798 #define KMA_RAND_9(sz) KMA_RAND_8(sz) .name[KMALLOC_RANDOM_START + 9] = "kmalloc-rnd-09-" #sz, 799 #define KMA_RAND_10(sz) KMA_RAND_9(sz) .name[KMALLOC_RANDOM_START + 10] = "kmalloc-rnd-10-" #sz, 800 #define KMA_RAND_11(sz) KMA_RAND_10(sz) .name[KMALLOC_RANDOM_START + 11] = "kmalloc-rnd-11-" #sz, 801 #define KMA_RAND_12(sz) KMA_RAND_11(sz) .name[KMALLOC_RANDOM_START + 12] = "kmalloc-rnd-12-" #sz, 802 #define KMA_RAND_13(sz) KMA_RAND_12(sz) .name[KMALLOC_RANDOM_START + 13] = "kmalloc-rnd-13-" #sz, 803 #define KMA_RAND_14(sz) KMA_RAND_13(sz) .name[KMALLOC_RANDOM_START + 14] = "kmalloc-rnd-14-" #sz, 804 #define KMA_RAND_15(sz) KMA_RAND_14(sz) .name[KMALLOC_RANDOM_START + 15] = "kmalloc-rnd-15-" #sz, 805 #else // CONFIG_RANDOM_KMALLOC_CACHES 806 #define KMALLOC_RANDOM_NAME(N, sz) 807 #endif 808 809 #define INIT_KMALLOC_INFO(__size, __short_size) \ 810 { \ 811 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \ 812 KMALLOC_RCL_NAME(__short_size) \ 813 KMALLOC_CGROUP_NAME(__short_size) \ 814 KMALLOC_DMA_NAME(__short_size) \ 815 KMALLOC_RANDOM_NAME(RANDOM_KMALLOC_CACHES_NR, __short_size) \ 816 .size = __size, \ 817 } 818 819 /* 820 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. 821 * kmalloc_index() supports up to 2^21=2MB, so the final entry of the table is 822 * kmalloc-2M. 823 */ 824 const struct kmalloc_info_struct kmalloc_info[] __initconst = { 825 INIT_KMALLOC_INFO(0, 0), 826 INIT_KMALLOC_INFO(96, 96), 827 INIT_KMALLOC_INFO(192, 192), 828 INIT_KMALLOC_INFO(8, 8), 829 INIT_KMALLOC_INFO(16, 16), 830 INIT_KMALLOC_INFO(32, 32), 831 INIT_KMALLOC_INFO(64, 64), 832 INIT_KMALLOC_INFO(128, 128), 833 INIT_KMALLOC_INFO(256, 256), 834 INIT_KMALLOC_INFO(512, 512), 835 INIT_KMALLOC_INFO(1024, 1k), 836 INIT_KMALLOC_INFO(2048, 2k), 837 INIT_KMALLOC_INFO(4096, 4k), 838 INIT_KMALLOC_INFO(8192, 8k), 839 INIT_KMALLOC_INFO(16384, 16k), 840 INIT_KMALLOC_INFO(32768, 32k), 841 INIT_KMALLOC_INFO(65536, 64k), 842 INIT_KMALLOC_INFO(131072, 128k), 843 INIT_KMALLOC_INFO(262144, 256k), 844 INIT_KMALLOC_INFO(524288, 512k), 845 INIT_KMALLOC_INFO(1048576, 1M), 846 INIT_KMALLOC_INFO(2097152, 2M) 847 }; 848 849 /* 850 * Patch up the size_index table if we have strange large alignment 851 * requirements for the kmalloc array. This is only the case for 852 * MIPS it seems. The standard arches will not generate any code here. 853 * 854 * Largest permitted alignment is 256 bytes due to the way we 855 * handle the index determination for the smaller caches. 856 * 857 * Make sure that nothing crazy happens if someone starts tinkering 858 * around with ARCH_KMALLOC_MINALIGN 859 */ 860 void __init setup_kmalloc_cache_index_table(void) 861 { 862 unsigned int i; 863 864 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || 865 !is_power_of_2(KMALLOC_MIN_SIZE)); 866 867 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { 868 unsigned int elem = size_index_elem(i); 869 870 if (elem >= ARRAY_SIZE(size_index)) 871 break; 872 size_index[elem] = KMALLOC_SHIFT_LOW; 873 } 874 875 if (KMALLOC_MIN_SIZE >= 64) { 876 /* 877 * The 96 byte sized cache is not used if the alignment 878 * is 64 byte. 879 */ 880 for (i = 64 + 8; i <= 96; i += 8) 881 size_index[size_index_elem(i)] = 7; 882 883 } 884 885 if (KMALLOC_MIN_SIZE >= 128) { 886 /* 887 * The 192 byte sized cache is not used if the alignment 888 * is 128 byte. Redirect kmalloc to use the 256 byte cache 889 * instead. 890 */ 891 for (i = 128 + 8; i <= 192; i += 8) 892 size_index[size_index_elem(i)] = 8; 893 } 894 } 895 896 static unsigned int __kmalloc_minalign(void) 897 { 898 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && 899 is_swiotlb_allocated()) 900 return ARCH_KMALLOC_MINALIGN; 901 return dma_get_cache_alignment(); 902 } 903 904 void __init 905 new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) 906 { 907 unsigned int minalign = __kmalloc_minalign(); 908 unsigned int aligned_size = kmalloc_info[idx].size; 909 int aligned_idx = idx; 910 911 if ((KMALLOC_RECLAIM != KMALLOC_NORMAL) && (type == KMALLOC_RECLAIM)) { 912 flags |= SLAB_RECLAIM_ACCOUNT; 913 } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) { 914 if (mem_cgroup_kmem_disabled()) { 915 kmalloc_caches[type][idx] = kmalloc_caches[KMALLOC_NORMAL][idx]; 916 return; 917 } 918 flags |= SLAB_ACCOUNT; 919 } else if (IS_ENABLED(CONFIG_ZONE_DMA) && (type == KMALLOC_DMA)) { 920 flags |= SLAB_CACHE_DMA; 921 } 922 923 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 924 if (type >= KMALLOC_RANDOM_START && type <= KMALLOC_RANDOM_END) 925 flags |= SLAB_NO_MERGE; 926 #endif 927 928 /* 929 * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for 930 * KMALLOC_NORMAL caches. 931 */ 932 if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_NORMAL)) 933 flags |= SLAB_NO_MERGE; 934 935 if (minalign > ARCH_KMALLOC_MINALIGN) { 936 aligned_size = ALIGN(aligned_size, minalign); 937 aligned_idx = __kmalloc_index(aligned_size, false); 938 } 939 940 if (!kmalloc_caches[type][aligned_idx]) 941 kmalloc_caches[type][aligned_idx] = create_kmalloc_cache( 942 kmalloc_info[aligned_idx].name[type], 943 aligned_size, flags); 944 if (idx != aligned_idx) 945 kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx]; 946 } 947 948 /* 949 * Create the kmalloc array. Some of the regular kmalloc arrays 950 * may already have been created because they were needed to 951 * enable allocations for slab creation. 952 */ 953 void __init create_kmalloc_caches(slab_flags_t flags) 954 { 955 int i; 956 enum kmalloc_cache_type type; 957 958 /* 959 * Including KMALLOC_CGROUP if CONFIG_MEMCG_KMEM defined 960 */ 961 for (type = KMALLOC_NORMAL; type < NR_KMALLOC_TYPES; type++) { 962 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { 963 if (!kmalloc_caches[type][i]) 964 new_kmalloc_cache(i, type, flags); 965 966 /* 967 * Caches that are not of the two-to-the-power-of size. 968 * These have to be created immediately after the 969 * earlier power of two caches 970 */ 971 if (KMALLOC_MIN_SIZE <= 32 && i == 6 && 972 !kmalloc_caches[type][1]) 973 new_kmalloc_cache(1, type, flags); 974 if (KMALLOC_MIN_SIZE <= 64 && i == 7 && 975 !kmalloc_caches[type][2]) 976 new_kmalloc_cache(2, type, flags); 977 } 978 } 979 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 980 random_kmalloc_seed = get_random_u64(); 981 #endif 982 983 /* Kmalloc array is now usable */ 984 slab_state = UP; 985 } 986 987 void free_large_kmalloc(struct folio *folio, void *object) 988 { 989 unsigned int order = folio_order(folio); 990 991 if (WARN_ON_ONCE(order == 0)) 992 pr_warn_once("object pointer: 0x%p\n", object); 993 994 kmemleak_free(object); 995 kasan_kfree_large(object); 996 kmsan_kfree_large(object); 997 998 mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B, 999 -(PAGE_SIZE << order)); 1000 __free_pages(folio_page(folio, 0), order); 1001 } 1002 1003 static void *__kmalloc_large_node(size_t size, gfp_t flags, int node); 1004 static __always_inline 1005 void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller) 1006 { 1007 struct kmem_cache *s; 1008 void *ret; 1009 1010 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) { 1011 ret = __kmalloc_large_node(size, flags, node); 1012 trace_kmalloc(caller, ret, size, 1013 PAGE_SIZE << get_order(size), flags, node); 1014 return ret; 1015 } 1016 1017 s = kmalloc_slab(size, flags, caller); 1018 1019 if (unlikely(ZERO_OR_NULL_PTR(s))) 1020 return s; 1021 1022 ret = __kmem_cache_alloc_node(s, flags, node, size, caller); 1023 ret = kasan_kmalloc(s, ret, size, flags); 1024 trace_kmalloc(caller, ret, size, s->size, flags, node); 1025 return ret; 1026 } 1027 1028 void *__kmalloc_node(size_t size, gfp_t flags, int node) 1029 { 1030 return __do_kmalloc_node(size, flags, node, _RET_IP_); 1031 } 1032 EXPORT_SYMBOL(__kmalloc_node); 1033 1034 void *__kmalloc(size_t size, gfp_t flags) 1035 { 1036 return __do_kmalloc_node(size, flags, NUMA_NO_NODE, _RET_IP_); 1037 } 1038 EXPORT_SYMBOL(__kmalloc); 1039 1040 void *__kmalloc_node_track_caller(size_t size, gfp_t flags, 1041 int node, unsigned long caller) 1042 { 1043 return __do_kmalloc_node(size, flags, node, caller); 1044 } 1045 EXPORT_SYMBOL(__kmalloc_node_track_caller); 1046 1047 /** 1048 * kfree - free previously allocated memory 1049 * @object: pointer returned by kmalloc() or kmem_cache_alloc() 1050 * 1051 * If @object is NULL, no operation is performed. 1052 */ 1053 void kfree(const void *object) 1054 { 1055 struct folio *folio; 1056 struct slab *slab; 1057 struct kmem_cache *s; 1058 1059 trace_kfree(_RET_IP_, object); 1060 1061 if (unlikely(ZERO_OR_NULL_PTR(object))) 1062 return; 1063 1064 folio = virt_to_folio(object); 1065 if (unlikely(!folio_test_slab(folio))) { 1066 free_large_kmalloc(folio, (void *)object); 1067 return; 1068 } 1069 1070 slab = folio_slab(folio); 1071 s = slab->slab_cache; 1072 __kmem_cache_free(s, (void *)object, _RET_IP_); 1073 } 1074 EXPORT_SYMBOL(kfree); 1075 1076 /** 1077 * __ksize -- Report full size of underlying allocation 1078 * @object: pointer to the object 1079 * 1080 * This should only be used internally to query the true size of allocations. 1081 * It is not meant to be a way to discover the usable size of an allocation 1082 * after the fact. Instead, use kmalloc_size_roundup(). Using memory beyond 1083 * the originally requested allocation size may trigger KASAN, UBSAN_BOUNDS, 1084 * and/or FORTIFY_SOURCE. 1085 * 1086 * Return: size of the actual memory used by @object in bytes 1087 */ 1088 size_t __ksize(const void *object) 1089 { 1090 struct folio *folio; 1091 1092 if (unlikely(object == ZERO_SIZE_PTR)) 1093 return 0; 1094 1095 folio = virt_to_folio(object); 1096 1097 if (unlikely(!folio_test_slab(folio))) { 1098 if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE)) 1099 return 0; 1100 if (WARN_ON(object != folio_address(folio))) 1101 return 0; 1102 return folio_size(folio); 1103 } 1104 1105 #ifdef CONFIG_SLUB_DEBUG 1106 skip_orig_size_check(folio_slab(folio)->slab_cache, object); 1107 #endif 1108 1109 return slab_ksize(folio_slab(folio)->slab_cache); 1110 } 1111 1112 void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size) 1113 { 1114 void *ret = __kmem_cache_alloc_node(s, gfpflags, NUMA_NO_NODE, 1115 size, _RET_IP_); 1116 1117 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE); 1118 1119 ret = kasan_kmalloc(s, ret, size, gfpflags); 1120 return ret; 1121 } 1122 EXPORT_SYMBOL(kmalloc_trace); 1123 1124 void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags, 1125 int node, size_t size) 1126 { 1127 void *ret = __kmem_cache_alloc_node(s, gfpflags, node, size, _RET_IP_); 1128 1129 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node); 1130 1131 ret = kasan_kmalloc(s, ret, size, gfpflags); 1132 return ret; 1133 } 1134 EXPORT_SYMBOL(kmalloc_node_trace); 1135 1136 gfp_t kmalloc_fix_flags(gfp_t flags) 1137 { 1138 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK; 1139 1140 flags &= ~GFP_SLAB_BUG_MASK; 1141 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n", 1142 invalid_mask, &invalid_mask, flags, &flags); 1143 dump_stack(); 1144 1145 return flags; 1146 } 1147 1148 /* 1149 * To avoid unnecessary overhead, we pass through large allocation requests 1150 * directly to the page allocator. We use __GFP_COMP, because we will need to 1151 * know the allocation order to free the pages properly in kfree. 1152 */ 1153 1154 static void *__kmalloc_large_node(size_t size, gfp_t flags, int node) 1155 { 1156 struct page *page; 1157 void *ptr = NULL; 1158 unsigned int order = get_order(size); 1159 1160 if (unlikely(flags & GFP_SLAB_BUG_MASK)) 1161 flags = kmalloc_fix_flags(flags); 1162 1163 flags |= __GFP_COMP; 1164 page = alloc_pages_node(node, flags, order); 1165 if (page) { 1166 ptr = page_address(page); 1167 mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, 1168 PAGE_SIZE << order); 1169 } 1170 1171 ptr = kasan_kmalloc_large(ptr, size, flags); 1172 /* As ptr might get tagged, call kmemleak hook after KASAN. */ 1173 kmemleak_alloc(ptr, size, 1, flags); 1174 kmsan_kmalloc_large(ptr, size, flags); 1175 1176 return ptr; 1177 } 1178 1179 void *kmalloc_large(size_t size, gfp_t flags) 1180 { 1181 void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE); 1182 1183 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size), 1184 flags, NUMA_NO_NODE); 1185 return ret; 1186 } 1187 EXPORT_SYMBOL(kmalloc_large); 1188 1189 void *kmalloc_large_node(size_t size, gfp_t flags, int node) 1190 { 1191 void *ret = __kmalloc_large_node(size, flags, node); 1192 1193 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size), 1194 flags, node); 1195 return ret; 1196 } 1197 EXPORT_SYMBOL(kmalloc_large_node); 1198 1199 #ifdef CONFIG_SLAB_FREELIST_RANDOM 1200 /* Randomize a generic freelist */ 1201 static void freelist_randomize(unsigned int *list, 1202 unsigned int count) 1203 { 1204 unsigned int rand; 1205 unsigned int i; 1206 1207 for (i = 0; i < count; i++) 1208 list[i] = i; 1209 1210 /* Fisher-Yates shuffle */ 1211 for (i = count - 1; i > 0; i--) { 1212 rand = get_random_u32_below(i + 1); 1213 swap(list[i], list[rand]); 1214 } 1215 } 1216 1217 /* Create a random sequence per cache */ 1218 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, 1219 gfp_t gfp) 1220 { 1221 1222 if (count < 2 || cachep->random_seq) 1223 return 0; 1224 1225 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp); 1226 if (!cachep->random_seq) 1227 return -ENOMEM; 1228 1229 freelist_randomize(cachep->random_seq, count); 1230 return 0; 1231 } 1232 1233 /* Destroy the per-cache random freelist sequence */ 1234 void cache_random_seq_destroy(struct kmem_cache *cachep) 1235 { 1236 kfree(cachep->random_seq); 1237 cachep->random_seq = NULL; 1238 } 1239 #endif /* CONFIG_SLAB_FREELIST_RANDOM */ 1240 1241 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) 1242 #ifdef CONFIG_SLAB 1243 #define SLABINFO_RIGHTS (0600) 1244 #else 1245 #define SLABINFO_RIGHTS (0400) 1246 #endif 1247 1248 static void print_slabinfo_header(struct seq_file *m) 1249 { 1250 /* 1251 * Output format version, so at least we can change it 1252 * without _too_ many complaints. 1253 */ 1254 #ifdef CONFIG_DEBUG_SLAB 1255 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 1256 #else 1257 seq_puts(m, "slabinfo - version: 2.1\n"); 1258 #endif 1259 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>"); 1260 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 1261 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 1262 #ifdef CONFIG_DEBUG_SLAB 1263 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 1264 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 1265 #endif 1266 seq_putc(m, '\n'); 1267 } 1268 1269 static void *slab_start(struct seq_file *m, loff_t *pos) 1270 { 1271 mutex_lock(&slab_mutex); 1272 return seq_list_start(&slab_caches, *pos); 1273 } 1274 1275 static void *slab_next(struct seq_file *m, void *p, loff_t *pos) 1276 { 1277 return seq_list_next(p, &slab_caches, pos); 1278 } 1279 1280 static void slab_stop(struct seq_file *m, void *p) 1281 { 1282 mutex_unlock(&slab_mutex); 1283 } 1284 1285 static void cache_show(struct kmem_cache *s, struct seq_file *m) 1286 { 1287 struct slabinfo sinfo; 1288 1289 memset(&sinfo, 0, sizeof(sinfo)); 1290 get_slabinfo(s, &sinfo); 1291 1292 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 1293 s->name, sinfo.active_objs, sinfo.num_objs, s->size, 1294 sinfo.objects_per_slab, (1 << sinfo.cache_order)); 1295 1296 seq_printf(m, " : tunables %4u %4u %4u", 1297 sinfo.limit, sinfo.batchcount, sinfo.shared); 1298 seq_printf(m, " : slabdata %6lu %6lu %6lu", 1299 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); 1300 slabinfo_show_stats(m, s); 1301 seq_putc(m, '\n'); 1302 } 1303 1304 static int slab_show(struct seq_file *m, void *p) 1305 { 1306 struct kmem_cache *s = list_entry(p, struct kmem_cache, list); 1307 1308 if (p == slab_caches.next) 1309 print_slabinfo_header(m); 1310 cache_show(s, m); 1311 return 0; 1312 } 1313 1314 void dump_unreclaimable_slab(void) 1315 { 1316 struct kmem_cache *s; 1317 struct slabinfo sinfo; 1318 1319 /* 1320 * Here acquiring slab_mutex is risky since we don't prefer to get 1321 * sleep in oom path. But, without mutex hold, it may introduce a 1322 * risk of crash. 1323 * Use mutex_trylock to protect the list traverse, dump nothing 1324 * without acquiring the mutex. 1325 */ 1326 if (!mutex_trylock(&slab_mutex)) { 1327 pr_warn("excessive unreclaimable slab but cannot dump stats\n"); 1328 return; 1329 } 1330 1331 pr_info("Unreclaimable slab info:\n"); 1332 pr_info("Name Used Total\n"); 1333 1334 list_for_each_entry(s, &slab_caches, list) { 1335 if (s->flags & SLAB_RECLAIM_ACCOUNT) 1336 continue; 1337 1338 get_slabinfo(s, &sinfo); 1339 1340 if (sinfo.num_objs > 0) 1341 pr_info("%-17s %10luKB %10luKB\n", s->name, 1342 (sinfo.active_objs * s->size) / 1024, 1343 (sinfo.num_objs * s->size) / 1024); 1344 } 1345 mutex_unlock(&slab_mutex); 1346 } 1347 1348 /* 1349 * slabinfo_op - iterator that generates /proc/slabinfo 1350 * 1351 * Output layout: 1352 * cache-name 1353 * num-active-objs 1354 * total-objs 1355 * object size 1356 * num-active-slabs 1357 * total-slabs 1358 * num-pages-per-slab 1359 * + further values on SMP and with statistics enabled 1360 */ 1361 static const struct seq_operations slabinfo_op = { 1362 .start = slab_start, 1363 .next = slab_next, 1364 .stop = slab_stop, 1365 .show = slab_show, 1366 }; 1367 1368 static int slabinfo_open(struct inode *inode, struct file *file) 1369 { 1370 return seq_open(file, &slabinfo_op); 1371 } 1372 1373 static const struct proc_ops slabinfo_proc_ops = { 1374 .proc_flags = PROC_ENTRY_PERMANENT, 1375 .proc_open = slabinfo_open, 1376 .proc_read = seq_read, 1377 .proc_write = slabinfo_write, 1378 .proc_lseek = seq_lseek, 1379 .proc_release = seq_release, 1380 }; 1381 1382 static int __init slab_proc_init(void) 1383 { 1384 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops); 1385 return 0; 1386 } 1387 module_init(slab_proc_init); 1388 1389 #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */ 1390 1391 static __always_inline __realloc_size(2) void * 1392 __do_krealloc(const void *p, size_t new_size, gfp_t flags) 1393 { 1394 void *ret; 1395 size_t ks; 1396 1397 /* Check for double-free before calling ksize. */ 1398 if (likely(!ZERO_OR_NULL_PTR(p))) { 1399 if (!kasan_check_byte(p)) 1400 return NULL; 1401 ks = ksize(p); 1402 } else 1403 ks = 0; 1404 1405 /* If the object still fits, repoison it precisely. */ 1406 if (ks >= new_size) { 1407 p = kasan_krealloc((void *)p, new_size, flags); 1408 return (void *)p; 1409 } 1410 1411 ret = kmalloc_track_caller(new_size, flags); 1412 if (ret && p) { 1413 /* Disable KASAN checks as the object's redzone is accessed. */ 1414 kasan_disable_current(); 1415 memcpy(ret, kasan_reset_tag(p), ks); 1416 kasan_enable_current(); 1417 } 1418 1419 return ret; 1420 } 1421 1422 /** 1423 * krealloc - reallocate memory. The contents will remain unchanged. 1424 * @p: object to reallocate memory for. 1425 * @new_size: how many bytes of memory are required. 1426 * @flags: the type of memory to allocate. 1427 * 1428 * The contents of the object pointed to are preserved up to the 1429 * lesser of the new and old sizes (__GFP_ZERO flag is effectively ignored). 1430 * If @p is %NULL, krealloc() behaves exactly like kmalloc(). If @new_size 1431 * is 0 and @p is not a %NULL pointer, the object pointed to is freed. 1432 * 1433 * Return: pointer to the allocated memory or %NULL in case of error 1434 */ 1435 void *krealloc(const void *p, size_t new_size, gfp_t flags) 1436 { 1437 void *ret; 1438 1439 if (unlikely(!new_size)) { 1440 kfree(p); 1441 return ZERO_SIZE_PTR; 1442 } 1443 1444 ret = __do_krealloc(p, new_size, flags); 1445 if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret)) 1446 kfree(p); 1447 1448 return ret; 1449 } 1450 EXPORT_SYMBOL(krealloc); 1451 1452 /** 1453 * kfree_sensitive - Clear sensitive information in memory before freeing 1454 * @p: object to free memory of 1455 * 1456 * The memory of the object @p points to is zeroed before freed. 1457 * If @p is %NULL, kfree_sensitive() does nothing. 1458 * 1459 * Note: this function zeroes the whole allocated buffer which can be a good 1460 * deal bigger than the requested buffer size passed to kmalloc(). So be 1461 * careful when using this function in performance sensitive code. 1462 */ 1463 void kfree_sensitive(const void *p) 1464 { 1465 size_t ks; 1466 void *mem = (void *)p; 1467 1468 ks = ksize(mem); 1469 if (ks) { 1470 kasan_unpoison_range(mem, ks); 1471 memzero_explicit(mem, ks); 1472 } 1473 kfree(mem); 1474 } 1475 EXPORT_SYMBOL(kfree_sensitive); 1476 1477 size_t ksize(const void *objp) 1478 { 1479 /* 1480 * We need to first check that the pointer to the object is valid. 1481 * The KASAN report printed from ksize() is more useful, then when 1482 * it's printed later when the behaviour could be undefined due to 1483 * a potential use-after-free or double-free. 1484 * 1485 * We use kasan_check_byte(), which is supported for the hardware 1486 * tag-based KASAN mode, unlike kasan_check_read/write(). 1487 * 1488 * If the pointed to memory is invalid, we return 0 to avoid users of 1489 * ksize() writing to and potentially corrupting the memory region. 1490 * 1491 * We want to perform the check before __ksize(), to avoid potentially 1492 * crashing in __ksize() due to accessing invalid metadata. 1493 */ 1494 if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp)) 1495 return 0; 1496 1497 return kfence_ksize(objp) ?: __ksize(objp); 1498 } 1499 EXPORT_SYMBOL(ksize); 1500 1501 /* Tracepoints definitions. */ 1502 EXPORT_TRACEPOINT_SYMBOL(kmalloc); 1503 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); 1504 EXPORT_TRACEPOINT_SYMBOL(kfree); 1505 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); 1506 1507 int should_failslab(struct kmem_cache *s, gfp_t gfpflags) 1508 { 1509 if (__should_failslab(s, gfpflags)) 1510 return -ENOMEM; 1511 return 0; 1512 } 1513 ALLOW_ERROR_INJECTION(should_failslab, ERRNO); 1514