1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Slab allocator functions that are independent of the allocator strategy 4 * 5 * (C) 2012 Christoph Lameter <cl@linux.com> 6 */ 7 #include <linux/slab.h> 8 9 #include <linux/mm.h> 10 #include <linux/poison.h> 11 #include <linux/interrupt.h> 12 #include <linux/memory.h> 13 #include <linux/cache.h> 14 #include <linux/compiler.h> 15 #include <linux/kfence.h> 16 #include <linux/module.h> 17 #include <linux/cpu.h> 18 #include <linux/uaccess.h> 19 #include <linux/seq_file.h> 20 #include <linux/proc_fs.h> 21 #include <linux/debugfs.h> 22 #include <linux/kasan.h> 23 #include <asm/cacheflush.h> 24 #include <asm/tlbflush.h> 25 #include <asm/page.h> 26 #include <linux/memcontrol.h> 27 28 #define CREATE_TRACE_POINTS 29 #include <trace/events/kmem.h> 30 31 #include "internal.h" 32 33 #include "slab.h" 34 35 enum slab_state slab_state; 36 LIST_HEAD(slab_caches); 37 DEFINE_MUTEX(slab_mutex); 38 struct kmem_cache *kmem_cache; 39 40 #ifdef CONFIG_HARDENED_USERCOPY 41 bool usercopy_fallback __ro_after_init = 42 IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK); 43 module_param(usercopy_fallback, bool, 0400); 44 MODULE_PARM_DESC(usercopy_fallback, 45 "WARN instead of reject usercopy whitelist violations"); 46 #endif 47 48 static LIST_HEAD(slab_caches_to_rcu_destroy); 49 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work); 50 static DECLARE_WORK(slab_caches_to_rcu_destroy_work, 51 slab_caches_to_rcu_destroy_workfn); 52 53 /* 54 * Set of flags that will prevent slab merging 55 */ 56 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ 57 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \ 58 SLAB_FAILSLAB | kasan_never_merge()) 59 60 #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \ 61 SLAB_CACHE_DMA32 | SLAB_ACCOUNT) 62 63 /* 64 * Merge control. If this is set then no merging of slab caches will occur. 65 */ 66 static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT); 67 68 static int __init setup_slab_nomerge(char *str) 69 { 70 slab_nomerge = true; 71 return 1; 72 } 73 74 static int __init setup_slab_merge(char *str) 75 { 76 slab_nomerge = false; 77 return 1; 78 } 79 80 #ifdef CONFIG_SLUB 81 __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0); 82 __setup_param("slub_merge", slub_merge, setup_slab_merge, 0); 83 #endif 84 85 __setup("slab_nomerge", setup_slab_nomerge); 86 __setup("slab_merge", setup_slab_merge); 87 88 /* 89 * Determine the size of a slab object 90 */ 91 unsigned int kmem_cache_size(struct kmem_cache *s) 92 { 93 return s->object_size; 94 } 95 EXPORT_SYMBOL(kmem_cache_size); 96 97 #ifdef CONFIG_DEBUG_VM 98 static int kmem_cache_sanity_check(const char *name, unsigned int size) 99 { 100 if (!name || in_interrupt() || size < sizeof(void *) || 101 size > KMALLOC_MAX_SIZE) { 102 pr_err("kmem_cache_create(%s) integrity check failed\n", name); 103 return -EINVAL; 104 } 105 106 WARN_ON(strchr(name, ' ')); /* It confuses parsers */ 107 return 0; 108 } 109 #else 110 static inline int kmem_cache_sanity_check(const char *name, unsigned int size) 111 { 112 return 0; 113 } 114 #endif 115 116 void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p) 117 { 118 size_t i; 119 120 for (i = 0; i < nr; i++) { 121 if (s) 122 kmem_cache_free(s, p[i]); 123 else 124 kfree(p[i]); 125 } 126 } 127 128 int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr, 129 void **p) 130 { 131 size_t i; 132 133 for (i = 0; i < nr; i++) { 134 void *x = p[i] = kmem_cache_alloc(s, flags); 135 if (!x) { 136 __kmem_cache_free_bulk(s, i, p); 137 return 0; 138 } 139 } 140 return i; 141 } 142 143 /* 144 * Figure out what the alignment of the objects will be given a set of 145 * flags, a user specified alignment and the size of the objects. 146 */ 147 static unsigned int calculate_alignment(slab_flags_t flags, 148 unsigned int align, unsigned int size) 149 { 150 /* 151 * If the user wants hardware cache aligned objects then follow that 152 * suggestion if the object is sufficiently large. 153 * 154 * The hardware cache alignment cannot override the specified 155 * alignment though. If that is greater then use it. 156 */ 157 if (flags & SLAB_HWCACHE_ALIGN) { 158 unsigned int ralign; 159 160 ralign = cache_line_size(); 161 while (size <= ralign / 2) 162 ralign /= 2; 163 align = max(align, ralign); 164 } 165 166 if (align < ARCH_SLAB_MINALIGN) 167 align = ARCH_SLAB_MINALIGN; 168 169 return ALIGN(align, sizeof(void *)); 170 } 171 172 /* 173 * Find a mergeable slab cache 174 */ 175 int slab_unmergeable(struct kmem_cache *s) 176 { 177 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE)) 178 return 1; 179 180 if (s->ctor) 181 return 1; 182 183 if (s->usersize) 184 return 1; 185 186 /* 187 * We may have set a slab to be unmergeable during bootstrap. 188 */ 189 if (s->refcount < 0) 190 return 1; 191 192 return 0; 193 } 194 195 struct kmem_cache *find_mergeable(unsigned int size, unsigned int align, 196 slab_flags_t flags, const char *name, void (*ctor)(void *)) 197 { 198 struct kmem_cache *s; 199 200 if (slab_nomerge) 201 return NULL; 202 203 if (ctor) 204 return NULL; 205 206 size = ALIGN(size, sizeof(void *)); 207 align = calculate_alignment(flags, align, size); 208 size = ALIGN(size, align); 209 flags = kmem_cache_flags(size, flags, name); 210 211 if (flags & SLAB_NEVER_MERGE) 212 return NULL; 213 214 list_for_each_entry_reverse(s, &slab_caches, list) { 215 if (slab_unmergeable(s)) 216 continue; 217 218 if (size > s->size) 219 continue; 220 221 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) 222 continue; 223 /* 224 * Check if alignment is compatible. 225 * Courtesy of Adrian Drzewiecki 226 */ 227 if ((s->size & ~(align - 1)) != s->size) 228 continue; 229 230 if (s->size - size >= sizeof(void *)) 231 continue; 232 233 if (IS_ENABLED(CONFIG_SLAB) && align && 234 (align > s->align || s->align % align)) 235 continue; 236 237 return s; 238 } 239 return NULL; 240 } 241 242 static struct kmem_cache *create_cache(const char *name, 243 unsigned int object_size, unsigned int align, 244 slab_flags_t flags, unsigned int useroffset, 245 unsigned int usersize, void (*ctor)(void *), 246 struct kmem_cache *root_cache) 247 { 248 struct kmem_cache *s; 249 int err; 250 251 if (WARN_ON(useroffset + usersize > object_size)) 252 useroffset = usersize = 0; 253 254 err = -ENOMEM; 255 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); 256 if (!s) 257 goto out; 258 259 s->name = name; 260 s->size = s->object_size = object_size; 261 s->align = align; 262 s->ctor = ctor; 263 s->useroffset = useroffset; 264 s->usersize = usersize; 265 266 err = __kmem_cache_create(s, flags); 267 if (err) 268 goto out_free_cache; 269 270 s->refcount = 1; 271 list_add(&s->list, &slab_caches); 272 out: 273 if (err) 274 return ERR_PTR(err); 275 return s; 276 277 out_free_cache: 278 kmem_cache_free(kmem_cache, s); 279 goto out; 280 } 281 282 /** 283 * kmem_cache_create_usercopy - Create a cache with a region suitable 284 * for copying to userspace 285 * @name: A string which is used in /proc/slabinfo to identify this cache. 286 * @size: The size of objects to be created in this cache. 287 * @align: The required alignment for the objects. 288 * @flags: SLAB flags 289 * @useroffset: Usercopy region offset 290 * @usersize: Usercopy region size 291 * @ctor: A constructor for the objects. 292 * 293 * Cannot be called within a interrupt, but can be interrupted. 294 * The @ctor is run when new pages are allocated by the cache. 295 * 296 * The flags are 297 * 298 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 299 * to catch references to uninitialised memory. 300 * 301 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check 302 * for buffer overruns. 303 * 304 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 305 * cacheline. This can be beneficial if you're counting cycles as closely 306 * as davem. 307 * 308 * Return: a pointer to the cache on success, NULL on failure. 309 */ 310 struct kmem_cache * 311 kmem_cache_create_usercopy(const char *name, 312 unsigned int size, unsigned int align, 313 slab_flags_t flags, 314 unsigned int useroffset, unsigned int usersize, 315 void (*ctor)(void *)) 316 { 317 struct kmem_cache *s = NULL; 318 const char *cache_name; 319 int err; 320 321 mutex_lock(&slab_mutex); 322 323 err = kmem_cache_sanity_check(name, size); 324 if (err) { 325 goto out_unlock; 326 } 327 328 /* Refuse requests with allocator specific flags */ 329 if (flags & ~SLAB_FLAGS_PERMITTED) { 330 err = -EINVAL; 331 goto out_unlock; 332 } 333 334 /* 335 * Some allocators will constraint the set of valid flags to a subset 336 * of all flags. We expect them to define CACHE_CREATE_MASK in this 337 * case, and we'll just provide them with a sanitized version of the 338 * passed flags. 339 */ 340 flags &= CACHE_CREATE_MASK; 341 342 /* Fail closed on bad usersize of useroffset values. */ 343 if (WARN_ON(!usersize && useroffset) || 344 WARN_ON(size < usersize || size - usersize < useroffset)) 345 usersize = useroffset = 0; 346 347 if (!usersize) 348 s = __kmem_cache_alias(name, size, align, flags, ctor); 349 if (s) 350 goto out_unlock; 351 352 cache_name = kstrdup_const(name, GFP_KERNEL); 353 if (!cache_name) { 354 err = -ENOMEM; 355 goto out_unlock; 356 } 357 358 s = create_cache(cache_name, size, 359 calculate_alignment(flags, align, size), 360 flags, useroffset, usersize, ctor, NULL); 361 if (IS_ERR(s)) { 362 err = PTR_ERR(s); 363 kfree_const(cache_name); 364 } 365 366 out_unlock: 367 mutex_unlock(&slab_mutex); 368 369 if (err) { 370 if (flags & SLAB_PANIC) 371 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", 372 name, err); 373 else { 374 pr_warn("kmem_cache_create(%s) failed with error %d\n", 375 name, err); 376 dump_stack(); 377 } 378 return NULL; 379 } 380 return s; 381 } 382 EXPORT_SYMBOL(kmem_cache_create_usercopy); 383 384 /** 385 * kmem_cache_create - Create a cache. 386 * @name: A string which is used in /proc/slabinfo to identify this cache. 387 * @size: The size of objects to be created in this cache. 388 * @align: The required alignment for the objects. 389 * @flags: SLAB flags 390 * @ctor: A constructor for the objects. 391 * 392 * Cannot be called within a interrupt, but can be interrupted. 393 * The @ctor is run when new pages are allocated by the cache. 394 * 395 * The flags are 396 * 397 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 398 * to catch references to uninitialised memory. 399 * 400 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check 401 * for buffer overruns. 402 * 403 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 404 * cacheline. This can be beneficial if you're counting cycles as closely 405 * as davem. 406 * 407 * Return: a pointer to the cache on success, NULL on failure. 408 */ 409 struct kmem_cache * 410 kmem_cache_create(const char *name, unsigned int size, unsigned int align, 411 slab_flags_t flags, void (*ctor)(void *)) 412 { 413 return kmem_cache_create_usercopy(name, size, align, flags, 0, 0, 414 ctor); 415 } 416 EXPORT_SYMBOL(kmem_cache_create); 417 418 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) 419 { 420 LIST_HEAD(to_destroy); 421 struct kmem_cache *s, *s2; 422 423 /* 424 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the 425 * @slab_caches_to_rcu_destroy list. The slab pages are freed 426 * through RCU and the associated kmem_cache are dereferenced 427 * while freeing the pages, so the kmem_caches should be freed only 428 * after the pending RCU operations are finished. As rcu_barrier() 429 * is a pretty slow operation, we batch all pending destructions 430 * asynchronously. 431 */ 432 mutex_lock(&slab_mutex); 433 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy); 434 mutex_unlock(&slab_mutex); 435 436 if (list_empty(&to_destroy)) 437 return; 438 439 rcu_barrier(); 440 441 list_for_each_entry_safe(s, s2, &to_destroy, list) { 442 kfence_shutdown_cache(s); 443 #ifdef SLAB_SUPPORTS_SYSFS 444 sysfs_slab_release(s); 445 #else 446 slab_kmem_cache_release(s); 447 #endif 448 } 449 } 450 451 static int shutdown_cache(struct kmem_cache *s) 452 { 453 /* free asan quarantined objects */ 454 kasan_cache_shutdown(s); 455 456 if (__kmem_cache_shutdown(s) != 0) 457 return -EBUSY; 458 459 list_del(&s->list); 460 461 if (s->flags & SLAB_TYPESAFE_BY_RCU) { 462 #ifdef SLAB_SUPPORTS_SYSFS 463 sysfs_slab_unlink(s); 464 #endif 465 list_add_tail(&s->list, &slab_caches_to_rcu_destroy); 466 schedule_work(&slab_caches_to_rcu_destroy_work); 467 } else { 468 kfence_shutdown_cache(s); 469 #ifdef SLAB_SUPPORTS_SYSFS 470 sysfs_slab_unlink(s); 471 sysfs_slab_release(s); 472 #else 473 slab_kmem_cache_release(s); 474 #endif 475 } 476 477 return 0; 478 } 479 480 void slab_kmem_cache_release(struct kmem_cache *s) 481 { 482 __kmem_cache_release(s); 483 kfree_const(s->name); 484 kmem_cache_free(kmem_cache, s); 485 } 486 487 void kmem_cache_destroy(struct kmem_cache *s) 488 { 489 int err; 490 491 if (unlikely(!s)) 492 return; 493 494 mutex_lock(&slab_mutex); 495 496 s->refcount--; 497 if (s->refcount) 498 goto out_unlock; 499 500 err = shutdown_cache(s); 501 if (err) { 502 pr_err("kmem_cache_destroy %s: Slab cache still has objects\n", 503 s->name); 504 dump_stack(); 505 } 506 out_unlock: 507 mutex_unlock(&slab_mutex); 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; 523 524 525 kasan_cache_shrink(cachep); 526 ret = __kmem_cache_shrink(cachep); 527 528 return ret; 529 } 530 EXPORT_SYMBOL(kmem_cache_shrink); 531 532 bool slab_is_available(void) 533 { 534 return slab_state >= UP; 535 } 536 537 #ifdef CONFIG_PRINTK 538 /** 539 * kmem_valid_obj - does the pointer reference a valid slab object? 540 * @object: pointer to query. 541 * 542 * Return: %true if the pointer is to a not-yet-freed object from 543 * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer 544 * is to an already-freed object, and %false otherwise. 545 */ 546 bool kmem_valid_obj(void *object) 547 { 548 struct page *page; 549 550 /* Some arches consider ZERO_SIZE_PTR to be a valid address. */ 551 if (object < (void *)PAGE_SIZE || !virt_addr_valid(object)) 552 return false; 553 page = virt_to_head_page(object); 554 return PageSlab(page); 555 } 556 EXPORT_SYMBOL_GPL(kmem_valid_obj); 557 558 /** 559 * kmem_dump_obj - Print available slab provenance information 560 * @object: slab object for which to find provenance information. 561 * 562 * This function uses pr_cont(), so that the caller is expected to have 563 * printed out whatever preamble is appropriate. The provenance information 564 * depends on the type of object and on how much debugging is enabled. 565 * For a slab-cache object, the fact that it is a slab object is printed, 566 * and, if available, the slab name, return address, and stack trace from 567 * the allocation 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 page *page; 578 unsigned long ptroffset; 579 struct kmem_obj_info kp = { }; 580 581 if (WARN_ON_ONCE(!virt_addr_valid(object))) 582 return; 583 page = virt_to_head_page(object); 584 if (WARN_ON_ONCE(!PageSlab(page))) { 585 pr_cont(" non-slab memory.\n"); 586 return; 587 } 588 kmem_obj_info(&kp, object, page); 589 if (kp.kp_slab_cache) 590 pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name); 591 else 592 pr_cont(" slab%s", cp); 593 if (kp.kp_objp) 594 pr_cont(" start %px", kp.kp_objp); 595 if (kp.kp_data_offset) 596 pr_cont(" data offset %lu", kp.kp_data_offset); 597 if (kp.kp_objp) { 598 ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset; 599 pr_cont(" pointer offset %lu", ptroffset); 600 } 601 if (kp.kp_slab_cache && kp.kp_slab_cache->usersize) 602 pr_cont(" size %u", kp.kp_slab_cache->usersize); 603 if (kp.kp_ret) 604 pr_cont(" allocated at %pS\n", kp.kp_ret); 605 else 606 pr_cont("\n"); 607 for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) { 608 if (!kp.kp_stack[i]) 609 break; 610 pr_info(" %pS\n", kp.kp_stack[i]); 611 } 612 } 613 EXPORT_SYMBOL_GPL(kmem_dump_obj); 614 #endif 615 616 #ifndef CONFIG_SLOB 617 /* Create a cache during boot when no slab services are available yet */ 618 void __init create_boot_cache(struct kmem_cache *s, const char *name, 619 unsigned int size, slab_flags_t flags, 620 unsigned int useroffset, unsigned int usersize) 621 { 622 int err; 623 unsigned int align = ARCH_KMALLOC_MINALIGN; 624 625 s->name = name; 626 s->size = s->object_size = size; 627 628 /* 629 * For power of two sizes, guarantee natural alignment for kmalloc 630 * caches, regardless of SL*B debugging options. 631 */ 632 if (is_power_of_2(size)) 633 align = max(align, size); 634 s->align = calculate_alignment(flags, align, size); 635 636 s->useroffset = useroffset; 637 s->usersize = usersize; 638 639 err = __kmem_cache_create(s, flags); 640 641 if (err) 642 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n", 643 name, size, err); 644 645 s->refcount = -1; /* Exempt from merging for now */ 646 } 647 648 struct kmem_cache *__init create_kmalloc_cache(const char *name, 649 unsigned int size, slab_flags_t flags, 650 unsigned int useroffset, unsigned int usersize) 651 { 652 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); 653 654 if (!s) 655 panic("Out of memory when creating slab %s\n", name); 656 657 create_boot_cache(s, name, size, flags, useroffset, usersize); 658 kasan_cache_create_kmalloc(s); 659 list_add(&s->list, &slab_caches); 660 s->refcount = 1; 661 return s; 662 } 663 664 struct kmem_cache * 665 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init = 666 { /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ }; 667 EXPORT_SYMBOL(kmalloc_caches); 668 669 /* 670 * Conversion table for small slabs sizes / 8 to the index in the 671 * kmalloc array. This is necessary for slabs < 192 since we have non power 672 * of two cache sizes there. The size of larger slabs can be determined using 673 * fls. 674 */ 675 static u8 size_index[24] __ro_after_init = { 676 3, /* 8 */ 677 4, /* 16 */ 678 5, /* 24 */ 679 5, /* 32 */ 680 6, /* 40 */ 681 6, /* 48 */ 682 6, /* 56 */ 683 6, /* 64 */ 684 1, /* 72 */ 685 1, /* 80 */ 686 1, /* 88 */ 687 1, /* 96 */ 688 7, /* 104 */ 689 7, /* 112 */ 690 7, /* 120 */ 691 7, /* 128 */ 692 2, /* 136 */ 693 2, /* 144 */ 694 2, /* 152 */ 695 2, /* 160 */ 696 2, /* 168 */ 697 2, /* 176 */ 698 2, /* 184 */ 699 2 /* 192 */ 700 }; 701 702 static inline unsigned int size_index_elem(unsigned int bytes) 703 { 704 return (bytes - 1) / 8; 705 } 706 707 /* 708 * Find the kmem_cache structure that serves a given size of 709 * allocation 710 */ 711 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) 712 { 713 unsigned int index; 714 715 if (size <= 192) { 716 if (!size) 717 return ZERO_SIZE_PTR; 718 719 index = size_index[size_index_elem(size)]; 720 } else { 721 if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE)) 722 return NULL; 723 index = fls(size - 1); 724 } 725 726 return kmalloc_caches[kmalloc_type(flags)][index]; 727 } 728 729 #ifdef CONFIG_ZONE_DMA 730 #define INIT_KMALLOC_INFO(__size, __short_size) \ 731 { \ 732 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \ 733 .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \ 734 .name[KMALLOC_DMA] = "dma-kmalloc-" #__short_size, \ 735 .size = __size, \ 736 } 737 #else 738 #define INIT_KMALLOC_INFO(__size, __short_size) \ 739 { \ 740 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \ 741 .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \ 742 .size = __size, \ 743 } 744 #endif 745 746 /* 747 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. 748 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is 749 * kmalloc-67108864. 750 */ 751 const struct kmalloc_info_struct kmalloc_info[] __initconst = { 752 INIT_KMALLOC_INFO(0, 0), 753 INIT_KMALLOC_INFO(96, 96), 754 INIT_KMALLOC_INFO(192, 192), 755 INIT_KMALLOC_INFO(8, 8), 756 INIT_KMALLOC_INFO(16, 16), 757 INIT_KMALLOC_INFO(32, 32), 758 INIT_KMALLOC_INFO(64, 64), 759 INIT_KMALLOC_INFO(128, 128), 760 INIT_KMALLOC_INFO(256, 256), 761 INIT_KMALLOC_INFO(512, 512), 762 INIT_KMALLOC_INFO(1024, 1k), 763 INIT_KMALLOC_INFO(2048, 2k), 764 INIT_KMALLOC_INFO(4096, 4k), 765 INIT_KMALLOC_INFO(8192, 8k), 766 INIT_KMALLOC_INFO(16384, 16k), 767 INIT_KMALLOC_INFO(32768, 32k), 768 INIT_KMALLOC_INFO(65536, 64k), 769 INIT_KMALLOC_INFO(131072, 128k), 770 INIT_KMALLOC_INFO(262144, 256k), 771 INIT_KMALLOC_INFO(524288, 512k), 772 INIT_KMALLOC_INFO(1048576, 1M), 773 INIT_KMALLOC_INFO(2097152, 2M), 774 INIT_KMALLOC_INFO(4194304, 4M), 775 INIT_KMALLOC_INFO(8388608, 8M), 776 INIT_KMALLOC_INFO(16777216, 16M), 777 INIT_KMALLOC_INFO(33554432, 32M), 778 INIT_KMALLOC_INFO(67108864, 64M) 779 }; 780 781 /* 782 * Patch up the size_index table if we have strange large alignment 783 * requirements for the kmalloc array. This is only the case for 784 * MIPS it seems. The standard arches will not generate any code here. 785 * 786 * Largest permitted alignment is 256 bytes due to the way we 787 * handle the index determination for the smaller caches. 788 * 789 * Make sure that nothing crazy happens if someone starts tinkering 790 * around with ARCH_KMALLOC_MINALIGN 791 */ 792 void __init setup_kmalloc_cache_index_table(void) 793 { 794 unsigned int i; 795 796 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || 797 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); 798 799 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { 800 unsigned int elem = size_index_elem(i); 801 802 if (elem >= ARRAY_SIZE(size_index)) 803 break; 804 size_index[elem] = KMALLOC_SHIFT_LOW; 805 } 806 807 if (KMALLOC_MIN_SIZE >= 64) { 808 /* 809 * The 96 byte size cache is not used if the alignment 810 * is 64 byte. 811 */ 812 for (i = 64 + 8; i <= 96; i += 8) 813 size_index[size_index_elem(i)] = 7; 814 815 } 816 817 if (KMALLOC_MIN_SIZE >= 128) { 818 /* 819 * The 192 byte sized cache is not used if the alignment 820 * is 128 byte. Redirect kmalloc to use the 256 byte cache 821 * instead. 822 */ 823 for (i = 128 + 8; i <= 192; i += 8) 824 size_index[size_index_elem(i)] = 8; 825 } 826 } 827 828 static void __init 829 new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) 830 { 831 if (type == KMALLOC_RECLAIM) 832 flags |= SLAB_RECLAIM_ACCOUNT; 833 834 kmalloc_caches[type][idx] = create_kmalloc_cache( 835 kmalloc_info[idx].name[type], 836 kmalloc_info[idx].size, flags, 0, 837 kmalloc_info[idx].size); 838 } 839 840 /* 841 * Create the kmalloc array. Some of the regular kmalloc arrays 842 * may already have been created because they were needed to 843 * enable allocations for slab creation. 844 */ 845 void __init create_kmalloc_caches(slab_flags_t flags) 846 { 847 int i; 848 enum kmalloc_cache_type type; 849 850 for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) { 851 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { 852 if (!kmalloc_caches[type][i]) 853 new_kmalloc_cache(i, type, flags); 854 855 /* 856 * Caches that are not of the two-to-the-power-of size. 857 * These have to be created immediately after the 858 * earlier power of two caches 859 */ 860 if (KMALLOC_MIN_SIZE <= 32 && i == 6 && 861 !kmalloc_caches[type][1]) 862 new_kmalloc_cache(1, type, flags); 863 if (KMALLOC_MIN_SIZE <= 64 && i == 7 && 864 !kmalloc_caches[type][2]) 865 new_kmalloc_cache(2, type, flags); 866 } 867 } 868 869 /* Kmalloc array is now usable */ 870 slab_state = UP; 871 872 #ifdef CONFIG_ZONE_DMA 873 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { 874 struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i]; 875 876 if (s) { 877 kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache( 878 kmalloc_info[i].name[KMALLOC_DMA], 879 kmalloc_info[i].size, 880 SLAB_CACHE_DMA | flags, 0, 881 kmalloc_info[i].size); 882 } 883 } 884 #endif 885 } 886 #endif /* !CONFIG_SLOB */ 887 888 gfp_t kmalloc_fix_flags(gfp_t flags) 889 { 890 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK; 891 892 flags &= ~GFP_SLAB_BUG_MASK; 893 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n", 894 invalid_mask, &invalid_mask, flags, &flags); 895 dump_stack(); 896 897 return flags; 898 } 899 900 /* 901 * To avoid unnecessary overhead, we pass through large allocation requests 902 * directly to the page allocator. We use __GFP_COMP, because we will need to 903 * know the allocation order to free the pages properly in kfree. 904 */ 905 void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) 906 { 907 void *ret = NULL; 908 struct page *page; 909 910 if (unlikely(flags & GFP_SLAB_BUG_MASK)) 911 flags = kmalloc_fix_flags(flags); 912 913 flags |= __GFP_COMP; 914 page = alloc_pages(flags, order); 915 if (likely(page)) { 916 ret = page_address(page); 917 mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, 918 PAGE_SIZE << order); 919 } 920 ret = kasan_kmalloc_large(ret, size, flags); 921 /* As ret might get tagged, call kmemleak hook after KASAN. */ 922 kmemleak_alloc(ret, size, 1, flags); 923 return ret; 924 } 925 EXPORT_SYMBOL(kmalloc_order); 926 927 #ifdef CONFIG_TRACING 928 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) 929 { 930 void *ret = kmalloc_order(size, flags, order); 931 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags); 932 return ret; 933 } 934 EXPORT_SYMBOL(kmalloc_order_trace); 935 #endif 936 937 #ifdef CONFIG_SLAB_FREELIST_RANDOM 938 /* Randomize a generic freelist */ 939 static void freelist_randomize(struct rnd_state *state, unsigned int *list, 940 unsigned int count) 941 { 942 unsigned int rand; 943 unsigned int i; 944 945 for (i = 0; i < count; i++) 946 list[i] = i; 947 948 /* Fisher-Yates shuffle */ 949 for (i = count - 1; i > 0; i--) { 950 rand = prandom_u32_state(state); 951 rand %= (i + 1); 952 swap(list[i], list[rand]); 953 } 954 } 955 956 /* Create a random sequence per cache */ 957 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, 958 gfp_t gfp) 959 { 960 struct rnd_state state; 961 962 if (count < 2 || cachep->random_seq) 963 return 0; 964 965 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp); 966 if (!cachep->random_seq) 967 return -ENOMEM; 968 969 /* Get best entropy at this stage of boot */ 970 prandom_seed_state(&state, get_random_long()); 971 972 freelist_randomize(&state, cachep->random_seq, count); 973 return 0; 974 } 975 976 /* Destroy the per-cache random freelist sequence */ 977 void cache_random_seq_destroy(struct kmem_cache *cachep) 978 { 979 kfree(cachep->random_seq); 980 cachep->random_seq = NULL; 981 } 982 #endif /* CONFIG_SLAB_FREELIST_RANDOM */ 983 984 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) 985 #ifdef CONFIG_SLAB 986 #define SLABINFO_RIGHTS (0600) 987 #else 988 #define SLABINFO_RIGHTS (0400) 989 #endif 990 991 static void print_slabinfo_header(struct seq_file *m) 992 { 993 /* 994 * Output format version, so at least we can change it 995 * without _too_ many complaints. 996 */ 997 #ifdef CONFIG_DEBUG_SLAB 998 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 999 #else 1000 seq_puts(m, "slabinfo - version: 2.1\n"); 1001 #endif 1002 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>"); 1003 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 1004 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 1005 #ifdef CONFIG_DEBUG_SLAB 1006 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 1007 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 1008 #endif 1009 seq_putc(m, '\n'); 1010 } 1011 1012 void *slab_start(struct seq_file *m, loff_t *pos) 1013 { 1014 mutex_lock(&slab_mutex); 1015 return seq_list_start(&slab_caches, *pos); 1016 } 1017 1018 void *slab_next(struct seq_file *m, void *p, loff_t *pos) 1019 { 1020 return seq_list_next(p, &slab_caches, pos); 1021 } 1022 1023 void slab_stop(struct seq_file *m, void *p) 1024 { 1025 mutex_unlock(&slab_mutex); 1026 } 1027 1028 static void cache_show(struct kmem_cache *s, struct seq_file *m) 1029 { 1030 struct slabinfo sinfo; 1031 1032 memset(&sinfo, 0, sizeof(sinfo)); 1033 get_slabinfo(s, &sinfo); 1034 1035 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 1036 s->name, sinfo.active_objs, sinfo.num_objs, s->size, 1037 sinfo.objects_per_slab, (1 << sinfo.cache_order)); 1038 1039 seq_printf(m, " : tunables %4u %4u %4u", 1040 sinfo.limit, sinfo.batchcount, sinfo.shared); 1041 seq_printf(m, " : slabdata %6lu %6lu %6lu", 1042 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); 1043 slabinfo_show_stats(m, s); 1044 seq_putc(m, '\n'); 1045 } 1046 1047 static int slab_show(struct seq_file *m, void *p) 1048 { 1049 struct kmem_cache *s = list_entry(p, struct kmem_cache, list); 1050 1051 if (p == slab_caches.next) 1052 print_slabinfo_header(m); 1053 cache_show(s, m); 1054 return 0; 1055 } 1056 1057 void dump_unreclaimable_slab(void) 1058 { 1059 struct kmem_cache *s; 1060 struct slabinfo sinfo; 1061 1062 /* 1063 * Here acquiring slab_mutex is risky since we don't prefer to get 1064 * sleep in oom path. But, without mutex hold, it may introduce a 1065 * risk of crash. 1066 * Use mutex_trylock to protect the list traverse, dump nothing 1067 * without acquiring the mutex. 1068 */ 1069 if (!mutex_trylock(&slab_mutex)) { 1070 pr_warn("excessive unreclaimable slab but cannot dump stats\n"); 1071 return; 1072 } 1073 1074 pr_info("Unreclaimable slab info:\n"); 1075 pr_info("Name Used Total\n"); 1076 1077 list_for_each_entry(s, &slab_caches, list) { 1078 if (s->flags & SLAB_RECLAIM_ACCOUNT) 1079 continue; 1080 1081 get_slabinfo(s, &sinfo); 1082 1083 if (sinfo.num_objs > 0) 1084 pr_info("%-17s %10luKB %10luKB\n", s->name, 1085 (sinfo.active_objs * s->size) / 1024, 1086 (sinfo.num_objs * s->size) / 1024); 1087 } 1088 mutex_unlock(&slab_mutex); 1089 } 1090 1091 #if defined(CONFIG_MEMCG_KMEM) 1092 int memcg_slab_show(struct seq_file *m, void *p) 1093 { 1094 /* 1095 * Deprecated. 1096 * Please, take a look at tools/cgroup/slabinfo.py . 1097 */ 1098 return 0; 1099 } 1100 #endif 1101 1102 /* 1103 * slabinfo_op - iterator that generates /proc/slabinfo 1104 * 1105 * Output layout: 1106 * cache-name 1107 * num-active-objs 1108 * total-objs 1109 * object size 1110 * num-active-slabs 1111 * total-slabs 1112 * num-pages-per-slab 1113 * + further values on SMP and with statistics enabled 1114 */ 1115 static const struct seq_operations slabinfo_op = { 1116 .start = slab_start, 1117 .next = slab_next, 1118 .stop = slab_stop, 1119 .show = slab_show, 1120 }; 1121 1122 static int slabinfo_open(struct inode *inode, struct file *file) 1123 { 1124 return seq_open(file, &slabinfo_op); 1125 } 1126 1127 static const struct proc_ops slabinfo_proc_ops = { 1128 .proc_flags = PROC_ENTRY_PERMANENT, 1129 .proc_open = slabinfo_open, 1130 .proc_read = seq_read, 1131 .proc_write = slabinfo_write, 1132 .proc_lseek = seq_lseek, 1133 .proc_release = seq_release, 1134 }; 1135 1136 static int __init slab_proc_init(void) 1137 { 1138 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops); 1139 return 0; 1140 } 1141 module_init(slab_proc_init); 1142 1143 #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */ 1144 1145 static __always_inline void *__do_krealloc(const void *p, size_t new_size, 1146 gfp_t flags) 1147 { 1148 void *ret; 1149 size_t ks; 1150 1151 /* Don't use instrumented ksize to allow precise KASAN poisoning. */ 1152 if (likely(!ZERO_OR_NULL_PTR(p))) { 1153 if (!kasan_check_byte(p)) 1154 return NULL; 1155 ks = kfence_ksize(p) ?: __ksize(p); 1156 } else 1157 ks = 0; 1158 1159 /* If the object still fits, repoison it precisely. */ 1160 if (ks >= new_size) { 1161 p = kasan_krealloc((void *)p, new_size, flags); 1162 return (void *)p; 1163 } 1164 1165 ret = kmalloc_track_caller(new_size, flags); 1166 if (ret && p) { 1167 /* Disable KASAN checks as the object's redzone is accessed. */ 1168 kasan_disable_current(); 1169 memcpy(ret, kasan_reset_tag(p), ks); 1170 kasan_enable_current(); 1171 } 1172 1173 return ret; 1174 } 1175 1176 /** 1177 * krealloc - reallocate memory. The contents will remain unchanged. 1178 * @p: object to reallocate memory for. 1179 * @new_size: how many bytes of memory are required. 1180 * @flags: the type of memory to allocate. 1181 * 1182 * The contents of the object pointed to are preserved up to the 1183 * lesser of the new and old sizes (__GFP_ZERO flag is effectively ignored). 1184 * If @p is %NULL, krealloc() behaves exactly like kmalloc(). If @new_size 1185 * is 0 and @p is not a %NULL pointer, the object pointed to is freed. 1186 * 1187 * Return: pointer to the allocated memory or %NULL in case of error 1188 */ 1189 void *krealloc(const void *p, size_t new_size, gfp_t flags) 1190 { 1191 void *ret; 1192 1193 if (unlikely(!new_size)) { 1194 kfree(p); 1195 return ZERO_SIZE_PTR; 1196 } 1197 1198 ret = __do_krealloc(p, new_size, flags); 1199 if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret)) 1200 kfree(p); 1201 1202 return ret; 1203 } 1204 EXPORT_SYMBOL(krealloc); 1205 1206 /** 1207 * kfree_sensitive - Clear sensitive information in memory before freeing 1208 * @p: object to free memory of 1209 * 1210 * The memory of the object @p points to is zeroed before freed. 1211 * If @p is %NULL, kfree_sensitive() does nothing. 1212 * 1213 * Note: this function zeroes the whole allocated buffer which can be a good 1214 * deal bigger than the requested buffer size passed to kmalloc(). So be 1215 * careful when using this function in performance sensitive code. 1216 */ 1217 void kfree_sensitive(const void *p) 1218 { 1219 size_t ks; 1220 void *mem = (void *)p; 1221 1222 ks = ksize(mem); 1223 if (ks) 1224 memzero_explicit(mem, ks); 1225 kfree(mem); 1226 } 1227 EXPORT_SYMBOL(kfree_sensitive); 1228 1229 /** 1230 * ksize - get the actual amount of memory allocated for a given object 1231 * @objp: Pointer to the object 1232 * 1233 * kmalloc may internally round up allocations and return more memory 1234 * than requested. ksize() can be used to determine the actual amount of 1235 * memory allocated. The caller may use this additional memory, even though 1236 * a smaller amount of memory was initially specified with the kmalloc call. 1237 * The caller must guarantee that objp points to a valid object previously 1238 * allocated with either kmalloc() or kmem_cache_alloc(). The object 1239 * must not be freed during the duration of the call. 1240 * 1241 * Return: size of the actual memory used by @objp in bytes 1242 */ 1243 size_t ksize(const void *objp) 1244 { 1245 size_t size; 1246 1247 /* 1248 * We need to first check that the pointer to the object is valid, and 1249 * only then unpoison the memory. The report printed from ksize() is 1250 * more useful, then when it's printed later when the behaviour could 1251 * be undefined due to a potential use-after-free or double-free. 1252 * 1253 * We use kasan_check_byte(), which is supported for the hardware 1254 * tag-based KASAN mode, unlike kasan_check_read/write(). 1255 * 1256 * If the pointed to memory is invalid, we return 0 to avoid users of 1257 * ksize() writing to and potentially corrupting the memory region. 1258 * 1259 * We want to perform the check before __ksize(), to avoid potentially 1260 * crashing in __ksize() due to accessing invalid metadata. 1261 */ 1262 if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp)) 1263 return 0; 1264 1265 size = kfence_ksize(objp) ?: __ksize(objp); 1266 /* 1267 * We assume that ksize callers could use whole allocated area, 1268 * so we need to unpoison this area. 1269 */ 1270 kasan_unpoison_range(objp, size); 1271 return size; 1272 } 1273 EXPORT_SYMBOL(ksize); 1274 1275 /* Tracepoints definitions. */ 1276 EXPORT_TRACEPOINT_SYMBOL(kmalloc); 1277 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); 1278 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); 1279 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); 1280 EXPORT_TRACEPOINT_SYMBOL(kfree); 1281 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); 1282 1283 int should_failslab(struct kmem_cache *s, gfp_t gfpflags) 1284 { 1285 if (__should_failslab(s, gfpflags)) 1286 return -ENOMEM; 1287 return 0; 1288 } 1289 ALLOW_ERROR_INJECTION(should_failslab, ERRNO); 1290