mm/kasan/shadow.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This file contains KASAN runtime code that manages shadow memory for
   4  * generic and software tag-based KASAN modes.
   5  *
   6  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   7  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
   8  *
   9  * Some code borrowed from https://github.com/xairy/kasan-prototype by
  10  *        Andrey Konovalov <andreyknvl@gmail.com>
  11  */
  12
  13 #include <linux/init.h>
  14 #include <linux/kasan.h>
  15 #include <linux/kernel.h>
  16 #include <linux/kfence.h>
  17 #include <linux/kmemleak.h>
  18 #include <linux/memory.h>
  19 #include <linux/mm.h>
  20 #include <linux/string.h>
  21 #include <linux/types.h>
  22 #include <linux/vmalloc.h>
  23
  24 #include <asm/cacheflush.h>
  25 #include <asm/tlbflush.h>
  26
  27 #include "kasan.h"
  28
  29 bool __kasan_check_read(const volatile void *p, unsigned int size)
  30 {
  31         return kasan_check_range((void *)p, size, false, _RET_IP_);
  32 }
  33 EXPORT_SYMBOL(__kasan_check_read);
  34
  35 bool __kasan_check_write(const volatile void *p, unsigned int size)
  36 {
  37         return kasan_check_range((void *)p, size, true, _RET_IP_);
  38 }
  39 EXPORT_SYMBOL(__kasan_check_write);
  40
  41 #if !defined(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX) && !defined(CONFIG_GENERIC_ENTRY)
  42 /*
  43  * CONFIG_GENERIC_ENTRY relies on compiler emitted mem*() calls to not be
  44  * instrumented. KASAN enabled toolchains should emit __asan_mem*() functions
  45  * for the sites they want to instrument.
  46  *
  47  * If we have a compiler that can instrument meminstrinsics, never override
  48  * these, so that non-instrumented files can safely consider them as builtins.
  49  */
  50 #undef memset
  51 void *memset(void *addr, int c, size_t len)
  52 {
  53         if (!kasan_check_range(addr, len, true, _RET_IP_))
  54                 return NULL;
  55
  56         return __memset(addr, c, len);
  57 }
  58
  59 #ifdef __HAVE_ARCH_MEMMOVE
  60 #undef memmove
  61 void *memmove(void *dest, const void *src, size_t len)
  62 {
  63         if (!kasan_check_range(src, len, false, _RET_IP_) ||
  64             !kasan_check_range(dest, len, true, _RET_IP_))
  65                 return NULL;
  66
  67         return __memmove(dest, src, len);
  68 }
  69 #endif
  70
  71 #undef memcpy
  72 void *memcpy(void *dest, const void *src, size_t len)
  73 {
  74         if (!kasan_check_range(src, len, false, _RET_IP_) ||
  75             !kasan_check_range(dest, len, true, _RET_IP_))
  76                 return NULL;
  77
  78         return __memcpy(dest, src, len);
  79 }
  80 #endif
  81
  82 void *__asan_memset(void *addr, int c, ssize_t len)
  83 {
  84         if (!kasan_check_range(addr, len, true, _RET_IP_))
  85                 return NULL;
  86
  87         return __memset(addr, c, len);
  88 }
  89 EXPORT_SYMBOL(__asan_memset);
  90
  91 #ifdef __HAVE_ARCH_MEMMOVE
  92 void *__asan_memmove(void *dest, const void *src, ssize_t len)
  93 {
  94         if (!kasan_check_range(src, len, false, _RET_IP_) ||
  95             !kasan_check_range(dest, len, true, _RET_IP_))
  96                 return NULL;
  97
  98         return __memmove(dest, src, len);
  99 }
 100 EXPORT_SYMBOL(__asan_memmove);
 101 #endif
 102
 103 void *__asan_memcpy(void *dest, const void *src, ssize_t len)
 104 {
 105         if (!kasan_check_range(src, len, false, _RET_IP_) ||
 106             !kasan_check_range(dest, len, true, _RET_IP_))
 107                 return NULL;
 108
 109         return __memcpy(dest, src, len);
 110 }
 111 EXPORT_SYMBOL(__asan_memcpy);
 112
 113 #ifdef CONFIG_KASAN_SW_TAGS
 114 void *__hwasan_memset(void *addr, int c, ssize_t len) __alias(__asan_memset);
 115 EXPORT_SYMBOL(__hwasan_memset);
 116 #ifdef __HAVE_ARCH_MEMMOVE
 117 void *__hwasan_memmove(void *dest, const void *src, ssize_t len) __alias(__asan_memmove);
 118 EXPORT_SYMBOL(__hwasan_memmove);
 119 #endif
 120 void *__hwasan_memcpy(void *dest, const void *src, ssize_t len) __alias(__asan_memcpy);
 121 EXPORT_SYMBOL(__hwasan_memcpy);
 122 #endif
 123
 124 void kasan_poison(const void *addr, size_t size, u8 value, bool init)
 125 {
 126         void *shadow_start, *shadow_end;
 127
 128         if (!kasan_arch_is_ready())
 129                 return;
 130
 131         /*
 132          * Perform shadow offset calculation based on untagged address, as
 133          * some of the callers (e.g. kasan_poison_object_data) pass tagged
 134          * addresses to this function.
 135          */
 136         addr = kasan_reset_tag(addr);
 137
 138         /* Skip KFENCE memory if called explicitly outside of sl*b. */
 139         if (is_kfence_address(addr))
 140                 return;
 141
 142         if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
 143                 return;
 144         if (WARN_ON(size & KASAN_GRANULE_MASK))
 145                 return;
 146
 147         shadow_start = kasan_mem_to_shadow(addr);
 148         shadow_end = kasan_mem_to_shadow(addr + size);
 149
 150         __memset(shadow_start, value, shadow_end - shadow_start);
 151 }
 152 EXPORT_SYMBOL(kasan_poison);
 153
 154 #ifdef CONFIG_KASAN_GENERIC
 155 void kasan_poison_last_granule(const void *addr, size_t size)
 156 {
 157         if (!kasan_arch_is_ready())
 158                 return;
 159
 160         if (size & KASAN_GRANULE_MASK) {
 161                 u8 *shadow = (u8 *)kasan_mem_to_shadow(addr + size);
 162                 *shadow = size & KASAN_GRANULE_MASK;
 163         }
 164 }
 165 #endif
 166
 167 void kasan_unpoison(const void *addr, size_t size, bool init)
 168 {
 169         u8 tag = get_tag(addr);
 170
 171         /*
 172          * Perform shadow offset calculation based on untagged address, as
 173          * some of the callers (e.g. kasan_unpoison_object_data) pass tagged
 174          * addresses to this function.
 175          */
 176         addr = kasan_reset_tag(addr);
 177
 178         /*
 179          * Skip KFENCE memory if called explicitly outside of sl*b. Also note
 180          * that calls to ksize(), where size is not a multiple of machine-word
 181          * size, would otherwise poison the invalid portion of the word.
 182          */
 183         if (is_kfence_address(addr))
 184                 return;
 185
 186         if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
 187                 return;
 188
 189         /* Unpoison all granules that cover the object. */
 190         kasan_poison(addr, round_up(size, KASAN_GRANULE_SIZE), tag, false);
 191
 192         /* Partially poison the last granule for the generic mode. */
 193         if (IS_ENABLED(CONFIG_KASAN_GENERIC))
 194                 kasan_poison_last_granule(addr, size);
 195 }
 196
 197 #ifdef CONFIG_MEMORY_HOTPLUG
 198 static bool shadow_mapped(unsigned long addr)
 199 {
 200         pgd_t *pgd = pgd_offset_k(addr);
 201         p4d_t *p4d;
 202         pud_t *pud;
 203         pmd_t *pmd;
 204         pte_t *pte;
 205
 206         if (pgd_none(*pgd))
 207                 return false;
 208         p4d = p4d_offset(pgd, addr);
 209         if (p4d_none(*p4d))
 210                 return false;
 211         pud = pud_offset(p4d, addr);
 212         if (pud_none(*pud))
 213                 return false;
 214
 215         /*
 216          * We can't use pud_large() or pud_huge(), the first one is
 217          * arch-specific, the last one depends on HUGETLB_PAGE.  So let's abuse
 218          * pud_bad(), if pud is bad then it's bad because it's huge.
 219          */
 220         if (pud_bad(*pud))
 221                 return true;
 222         pmd = pmd_offset(pud, addr);
 223         if (pmd_none(*pmd))
 224                 return false;
 225
 226         if (pmd_bad(*pmd))
 227                 return true;
 228         pte = pte_offset_kernel(pmd, addr);
 229         return !pte_none(ptep_get(pte));
 230 }
 231
 232 static int __meminit kasan_mem_notifier(struct notifier_block *nb,
 233                         unsigned long action, void *data)
 234 {
 235         struct memory_notify *mem_data = data;
 236         unsigned long nr_shadow_pages, start_kaddr, shadow_start;
 237         unsigned long shadow_end, shadow_size;
 238
 239         nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
 240         start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
 241         shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
 242         shadow_size = nr_shadow_pages << PAGE_SHIFT;
 243         shadow_end = shadow_start + shadow_size;
 244
 245         if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
 246                 WARN_ON(start_kaddr % KASAN_MEMORY_PER_SHADOW_PAGE))
 247                 return NOTIFY_BAD;
 248
 249         switch (action) {
 250         case MEM_GOING_ONLINE: {
 251                 void *ret;
 252
 253                 /*
 254                  * If shadow is mapped already than it must have been mapped
 255                  * during the boot. This could happen if we onlining previously
 256                  * offlined memory.
 257                  */
 258                 if (shadow_mapped(shadow_start))
 259                         return NOTIFY_OK;
 260
 261                 ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
 262                                         shadow_end, GFP_KERNEL,
 263                                         PAGE_KERNEL, VM_NO_GUARD,
 264                                         pfn_to_nid(mem_data->start_pfn),
 265                                         __builtin_return_address(0));
 266                 if (!ret)
 267                         return NOTIFY_BAD;
 268
 269                 kmemleak_ignore(ret);
 270                 return NOTIFY_OK;
 271         }
 272         case MEM_CANCEL_ONLINE:
 273         case MEM_OFFLINE: {
 274                 struct vm_struct *vm;
 275
 276                 /*
 277                  * shadow_start was either mapped during boot by kasan_init()
 278                  * or during memory online by __vmalloc_node_range().
 279                  * In the latter case we can use vfree() to free shadow.
 280                  * Non-NULL result of the find_vm_area() will tell us if
 281                  * that was the second case.
 282                  *
 283                  * Currently it's not possible to free shadow mapped
 284                  * during boot by kasan_init(). It's because the code
 285                  * to do that hasn't been written yet. So we'll just
 286                  * leak the memory.
 287                  */
 288                 vm = find_vm_area((void *)shadow_start);
 289                 if (vm)
 290                         vfree((void *)shadow_start);
 291         }
 292         }
 293
 294         return NOTIFY_OK;
 295 }
 296
 297 static int __init kasan_memhotplug_init(void)
 298 {
 299         hotplug_memory_notifier(kasan_mem_notifier, DEFAULT_CALLBACK_PRI);
 300
 301         return 0;
 302 }
 303
 304 core_initcall(kasan_memhotplug_init);
 305 #endif
 306
 307 #ifdef CONFIG_KASAN_VMALLOC
 308
 309 void __init __weak kasan_populate_early_vm_area_shadow(void *start,
 310                                                        unsigned long size)
 311 {
 312 }
 313
 314 static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
 315                                       void *unused)
 316 {
 317         unsigned long page;
 318         pte_t pte;
 319
 320         if (likely(!pte_none(ptep_get(ptep))))
 321                 return 0;
 322
 323         page = __get_free_page(GFP_KERNEL);
 324         if (!page)
 325                 return -ENOMEM;
 326
 327         memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE);
 328         pte = pfn_pte(PFN_DOWN(__pa(page)), PAGE_KERNEL);
 329
 330         spin_lock(&init_mm.page_table_lock);
 331         if (likely(pte_none(ptep_get(ptep)))) {
 332                 set_pte_at(&init_mm, addr, ptep, pte);
 333                 page = 0;
 334         }
 335         spin_unlock(&init_mm.page_table_lock);
 336         if (page)
 337                 free_page(page);
 338         return 0;
 339 }
 340
 341 int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
 342 {
 343         unsigned long shadow_start, shadow_end;
 344         int ret;
 345
 346         if (!kasan_arch_is_ready())
 347                 return 0;
 348
 349         if (!is_vmalloc_or_module_addr((void *)addr))
 350                 return 0;
 351
 352         shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr);
 353         shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size);
 354
 355         /*
 356          * User Mode Linux maps enough shadow memory for all of virtual memory
 357          * at boot, so doesn't need to allocate more on vmalloc, just clear it.
 358          *
 359          * The remaining CONFIG_UML checks in this file exist for the same
 360          * reason.
 361          */
 362         if (IS_ENABLED(CONFIG_UML)) {
 363                 __memset((void *)shadow_start, KASAN_VMALLOC_INVALID, shadow_end - shadow_start);
 364                 return 0;
 365         }
 366
 367         shadow_start = PAGE_ALIGN_DOWN(shadow_start);
 368         shadow_end = PAGE_ALIGN(shadow_end);
 369
 370         ret = apply_to_page_range(&init_mm, shadow_start,
 371                                   shadow_end - shadow_start,
 372                                   kasan_populate_vmalloc_pte, NULL);
 373         if (ret)
 374                 return ret;
 375
 376         flush_cache_vmap(shadow_start, shadow_end);
 377
 378         /*
 379          * We need to be careful about inter-cpu effects here. Consider:
 380          *
 381          *   CPU#0                                CPU#1
 382          * WRITE_ONCE(p, vmalloc(100));         while (x = READ_ONCE(p)) ;
 383          *                                      p[99] = 1;
 384          *
 385          * With compiler instrumentation, that ends up looking like this:
 386          *
 387          *   CPU#0                                CPU#1
 388          * // vmalloc() allocates memory
 389          * // let a = area->addr
 390          * // we reach kasan_populate_vmalloc
 391          * // and call kasan_unpoison:
 392          * STORE shadow(a), unpoison_val
 393          * ...
 394          * STORE shadow(a+99), unpoison_val     x = LOAD p
 395          * // rest of vmalloc process           <data dependency>
 396          * STORE p, a                           LOAD shadow(x+99)
 397          *
 398          * If there is no barrier between the end of unpoisoning the shadow
 399          * and the store of the result to p, the stores could be committed
 400          * in a different order by CPU#0, and CPU#1 could erroneously observe
 401          * poison in the shadow.
 402          *
 403          * We need some sort of barrier between the stores.
 404          *
 405          * In the vmalloc() case, this is provided by a smp_wmb() in
 406          * clear_vm_uninitialized_flag(). In the per-cpu allocator and in
 407          * get_vm_area() and friends, the caller gets shadow allocated but
 408          * doesn't have any pages mapped into the virtual address space that
 409          * has been reserved. Mapping those pages in will involve taking and
 410          * releasing a page-table lock, which will provide the barrier.
 411          */
 412
 413         return 0;
 414 }
 415
 416 static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,
 417                                         void *unused)
 418 {
 419         unsigned long page;
 420
 421         page = (unsigned long)__va(pte_pfn(ptep_get(ptep)) << PAGE_SHIFT);
 422
 423         spin_lock(&init_mm.page_table_lock);
 424
 425         if (likely(!pte_none(ptep_get(ptep)))) {
 426                 pte_clear(&init_mm, addr, ptep);
 427                 free_page(page);
 428         }
 429         spin_unlock(&init_mm.page_table_lock);
 430
 431         return 0;
 432 }
 433
 434 /*
 435  * Release the backing for the vmalloc region [start, end), which
 436  * lies within the free region [free_region_start, free_region_end).
 437  *
 438  * This can be run lazily, long after the region was freed. It runs
 439  * under vmap_area_lock, so it's not safe to interact with the vmalloc/vmap
 440  * infrastructure.
 441  *
 442  * How does this work?
 443  * -------------------
 444  *
 445  * We have a region that is page aligned, labeled as A.
 446  * That might not map onto the shadow in a way that is page-aligned:
 447  *
 448  *                    start                     end
 449  *                    v                         v
 450  * |????????|????????|AAAAAAAA|AA....AA|AAAAAAAA|????????| < vmalloc
 451  *  -------- -------- --------          -------- --------
 452  *      |        |       |                 |        |
 453  *      |        |       |         /-------/        |
 454  *      \-------\|/------/         |/---------------/
 455  *              |||                ||
 456  *             |??AAAAAA|AAAAAAAA|AA??????|                < shadow
 457  *                 (1)      (2)      (3)
 458  *
 459  * First we align the start upwards and the end downwards, so that the
 460  * shadow of the region aligns with shadow page boundaries. In the
 461  * example, this gives us the shadow page (2). This is the shadow entirely
 462  * covered by this allocation.
 463  *
 464  * Then we have the tricky bits. We want to know if we can free the
 465  * partially covered shadow pages - (1) and (3) in the example. For this,
 466  * we are given the start and end of the free region that contains this
 467  * allocation. Extending our previous example, we could have:
 468  *
 469  *  free_region_start                                    free_region_end
 470  *  |                 start                     end      |
 471  *  v                 v                         v        v
 472  * |FFFFFFFF|FFFFFFFF|AAAAAAAA|AA....AA|AAAAAAAA|FFFFFFFF| < vmalloc
 473  *  -------- -------- --------          -------- --------
 474  *      |        |       |                 |        |
 475  *      |        |       |         /-------/        |
 476  *      \-------\|/------/         |/---------------/
 477  *              |||                ||
 478  *             |FFAAAAAA|AAAAAAAA|AAF?????|                < shadow
 479  *                 (1)      (2)      (3)
 480  *
 481  * Once again, we align the start of the free region up, and the end of
 482  * the free region down so that the shadow is page aligned. So we can free
 483  * page (1) - we know no allocation currently uses anything in that page,
 484  * because all of it is in the vmalloc free region. But we cannot free
 485  * page (3), because we can't be sure that the rest of it is unused.
 486  *
 487  * We only consider pages that contain part of the original region for
 488  * freeing: we don't try to free other pages from the free region or we'd
 489  * end up trying to free huge chunks of virtual address space.
 490  *
 491  * Concurrency
 492  * -----------
 493  *
 494  * How do we know that we're not freeing a page that is simultaneously
 495  * being used for a fresh allocation in kasan_populate_vmalloc(_pte)?
 496  *
 497  * We _can_ have kasan_release_vmalloc and kasan_populate_vmalloc running
 498  * at the same time. While we run under free_vmap_area_lock, the population
 499  * code does not.
 500  *
 501  * free_vmap_area_lock instead operates to ensure that the larger range
 502  * [free_region_start, free_region_end) is safe: because __alloc_vmap_area and
 503  * the per-cpu region-finding algorithm both run under free_vmap_area_lock,
 504  * no space identified as free will become used while we are running. This
 505  * means that so long as we are careful with alignment and only free shadow
 506  * pages entirely covered by the free region, we will not run in to any
 507  * trouble - any simultaneous allocations will be for disjoint regions.
 508  */
 509 void kasan_release_vmalloc(unsigned long start, unsigned long end,
 510                            unsigned long free_region_start,
 511                            unsigned long free_region_end)
 512 {
 513         void *shadow_start, *shadow_end;
 514         unsigned long region_start, region_end;
 515         unsigned long size;
 516
 517         if (!kasan_arch_is_ready())
 518                 return;
 519
 520         region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE);
 521         region_end = ALIGN_DOWN(end, KASAN_MEMORY_PER_SHADOW_PAGE);
 522
 523         free_region_start = ALIGN(free_region_start, KASAN_MEMORY_PER_SHADOW_PAGE);
 524
 525         if (start != region_start &&
 526             free_region_start < region_start)
 527                 region_start -= KASAN_MEMORY_PER_SHADOW_PAGE;
 528
 529         free_region_end = ALIGN_DOWN(free_region_end, KASAN_MEMORY_PER_SHADOW_PAGE);
 530
 531         if (end != region_end &&
 532             free_region_end > region_end)
 533                 region_end += KASAN_MEMORY_PER_SHADOW_PAGE;
 534
 535         shadow_start = kasan_mem_to_shadow((void *)region_start);
 536         shadow_end = kasan_mem_to_shadow((void *)region_end);
 537
 538         if (shadow_end > shadow_start) {
 539                 size = shadow_end - shadow_start;
 540                 if (IS_ENABLED(CONFIG_UML)) {
 541                         __memset(shadow_start, KASAN_SHADOW_INIT, shadow_end - shadow_start);
 542                         return;
 543                 }
 544                 apply_to_existing_page_range(&init_mm,
 545                                              (unsigned long)shadow_start,
 546                                              size, kasan_depopulate_vmalloc_pte,
 547                                              NULL);
 548                 flush_tlb_kernel_range((unsigned long)shadow_start,
 549                                        (unsigned long)shadow_end);
 550         }
 551 }
 552
 553 void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
 554                                kasan_vmalloc_flags_t flags)
 555 {
 556         /*
 557          * Software KASAN modes unpoison both VM_ALLOC and non-VM_ALLOC
 558          * mappings, so the KASAN_VMALLOC_VM_ALLOC flag is ignored.
 559          * Software KASAN modes can't optimize zeroing memory by combining it
 560          * with setting memory tags, so the KASAN_VMALLOC_INIT flag is ignored.
 561          */
 562
 563         if (!kasan_arch_is_ready())
 564                 return (void *)start;
 565
 566         if (!is_vmalloc_or_module_addr(start))
 567                 return (void *)start;
 568
 569         /*
 570          * Don't tag executable memory with the tag-based mode.
 571          * The kernel doesn't tolerate having the PC register tagged.
 572          */
 573         if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) &&
 574             !(flags & KASAN_VMALLOC_PROT_NORMAL))
 575                 return (void *)start;
 576
 577         start = set_tag(start, kasan_random_tag());
 578         kasan_unpoison(start, size, false);
 579         return (void *)start;
 580 }
 581
 582 /*
 583  * Poison the shadow for a vmalloc region. Called as part of the
 584  * freeing process at the time the region is freed.
 585  */
 586 void __kasan_poison_vmalloc(const void *start, unsigned long size)
 587 {
 588         if (!kasan_arch_is_ready())
 589                 return;
 590
 591         if (!is_vmalloc_or_module_addr(start))
 592                 return;
 593
 594         size = round_up(size, KASAN_GRANULE_SIZE);
 595         kasan_poison(start, size, KASAN_VMALLOC_INVALID, false);
 596 }
 597
 598 #else /* CONFIG_KASAN_VMALLOC */
 599
 600 int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask)
 601 {
 602         void *ret;
 603         size_t scaled_size;
 604         size_t shadow_size;
 605         unsigned long shadow_start;
 606
 607         shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
 608         scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>
 609                                 KASAN_SHADOW_SCALE_SHIFT;
 610         shadow_size = round_up(scaled_size, PAGE_SIZE);
 611
 612         if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
 613                 return -EINVAL;
 614
 615         if (IS_ENABLED(CONFIG_UML)) {
 616                 __memset((void *)shadow_start, KASAN_SHADOW_INIT, shadow_size);
 617                 return 0;
 618         }
 619
 620         ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
 621                         shadow_start + shadow_size,
 622                         GFP_KERNEL,
 623                         PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
 624                         __builtin_return_address(0));
 625
 626         if (ret) {
 627                 struct vm_struct *vm = find_vm_area(addr);
 628                 __memset(ret, KASAN_SHADOW_INIT, shadow_size);
 629                 vm->flags |= VM_KASAN;
 630                 kmemleak_ignore(ret);
 631
 632                 if (vm->flags & VM_DEFER_KMEMLEAK)
 633                         kmemleak_vmalloc(vm, size, gfp_mask);
 634
 635                 return 0;
 636         }
 637
 638         return -ENOMEM;
 639 }
 640
 641 void kasan_free_module_shadow(const struct vm_struct *vm)
 642 {
 643         if (IS_ENABLED(CONFIG_UML))
 644                 return;
 645
 646         if (vm->flags & VM_KASAN)
 647                 vfree(kasan_mem_to_shadow(vm->addr));
 648 }
 649
 650 #endif