1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * This file contains core generic KASAN code.
  4 *
  5 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
  6 * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
  7 *
  8 * Some code borrowed from https://github.com/xairy/kasan-prototype by
  9 *        Andrey Konovalov <andreyknvl@gmail.com>
 10 *
 11 * This program is free software; you can redistribute it and/or modify
 12 * it under the terms of the GNU General Public License version 2 as
 13 * published by the Free Software Foundation.
 14 *
 15 */
 16
 17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 18#define DISABLE_BRANCH_PROFILING
 19
 20#include <linux/export.h>
 21#include <linux/interrupt.h>
 22#include <linux/init.h>
 23#include <linux/kasan.h>
 24#include <linux/kernel.h>
 25#include <linux/kmemleak.h>
 26#include <linux/linkage.h>
 27#include <linux/memblock.h>
 28#include <linux/memory.h>
 29#include <linux/mm.h>
 30#include <linux/module.h>
 31#include <linux/printk.h>
 32#include <linux/sched.h>
 33#include <linux/sched/task_stack.h>
 34#include <linux/slab.h>
 35#include <linux/stacktrace.h>
 36#include <linux/string.h>
 37#include <linux/types.h>
 38#include <linux/vmalloc.h>
 39#include <linux/bug.h>
 40
 41#include "kasan.h"
 42#include "../slab.h"
 43
 44/*
 45 * All functions below always inlined so compiler could
 46 * perform better optimizations in each of __asan_loadX/__assn_storeX
 47 * depending on memory access size X.
 48 */
 49
 50static __always_inline bool memory_is_poisoned_1(unsigned long addr)
 51{
 52	s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
 53
 54	if (unlikely(shadow_value)) {
 55		s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
 56		return unlikely(last_accessible_byte >= shadow_value);
 57	}
 58
 59	return false;
 60}
 61
 62static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr,
 63						unsigned long size)
 64{
 65	u8 *shadow_addr = (u8 *)kasan_mem_to_shadow((void *)addr);
 66
 67	/*
 68	 * Access crosses 8(shadow size)-byte boundary. Such access maps
 69	 * into 2 shadow bytes, so we need to check them both.
 70	 */
 71	if (unlikely(((addr + size - 1) & KASAN_SHADOW_MASK) < size - 1))
 72		return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
 73
 74	return memory_is_poisoned_1(addr + size - 1);
 75}
 76
 77static __always_inline bool memory_is_poisoned_16(unsigned long addr)
 78{
 79	u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 80
 81	/* Unaligned 16-bytes access maps into 3 shadow bytes. */
 82	if (unlikely(!IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 83		return *shadow_addr || memory_is_poisoned_1(addr + 15);
 84
 85	return *shadow_addr;
 86}
 87
 88static __always_inline unsigned long bytes_is_nonzero(const u8 *start,
 89					size_t size)
 90{
 91	while (size) {
 92		if (unlikely(*start))
 93			return (unsigned long)start;
 94		start++;
 95		size--;
 96	}
 97
 98	return 0;
 99}
100
101static __always_inline unsigned long memory_is_nonzero(const void *start,
102						const void *end)
103{
104	unsigned int words;
105	unsigned long ret;
106	unsigned int prefix = (unsigned long)start % 8;
107
108	if (end - start <= 16)
109		return bytes_is_nonzero(start, end - start);
110
111	if (prefix) {
112		prefix = 8 - prefix;
113		ret = bytes_is_nonzero(start, prefix);
114		if (unlikely(ret))
115			return ret;
116		start += prefix;
117	}
118
119	words = (end - start) / 8;
120	while (words) {
121		if (unlikely(*(u64 *)start))
122			return bytes_is_nonzero(start, 8);
123		start += 8;
124		words--;
125	}
126
127	return bytes_is_nonzero(start, (end - start) % 8);
128}
129
130static __always_inline bool memory_is_poisoned_n(unsigned long addr,
131						size_t size)
132{
133	unsigned long ret;
134
135	ret = memory_is_nonzero(kasan_mem_to_shadow((void *)addr),
136			kasan_mem_to_shadow((void *)addr + size - 1) + 1);
137
138	if (unlikely(ret)) {
139		unsigned long last_byte = addr + size - 1;
140		s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
141
142		if (unlikely(ret != (unsigned long)last_shadow ||
143			((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
144			return true;
145	}
146	return false;
147}
148
149static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
150{
151	if (__builtin_constant_p(size)) {
152		switch (size) {
153		case 1:
154			return memory_is_poisoned_1(addr);
155		case 2:
156		case 4:
157		case 8:
158			return memory_is_poisoned_2_4_8(addr, size);
159		case 16:
160			return memory_is_poisoned_16(addr);
161		default:
162			BUILD_BUG();
163		}
164	}
165
166	return memory_is_poisoned_n(addr, size);
167}
168
169static __always_inline bool check_memory_region_inline(unsigned long addr,
170						size_t size, bool write,
171						unsigned long ret_ip)
172{
173	if (unlikely(size == 0))
174		return true;
175
 
 
 
176	if (unlikely((void *)addr <
177		kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
178		kasan_report(addr, size, write, ret_ip);
179		return false;
180	}
181
182	if (likely(!memory_is_poisoned(addr, size)))
183		return true;
184
185	kasan_report(addr, size, write, ret_ip);
186	return false;
187}
188
189bool check_memory_region(unsigned long addr, size_t size, bool write,
190				unsigned long ret_ip)
191{
192	return check_memory_region_inline(addr, size, write, ret_ip);
193}
194
195void kasan_cache_shrink(struct kmem_cache *cache)
196{
197	quarantine_remove_cache(cache);
198}
199
200void kasan_cache_shutdown(struct kmem_cache *cache)
201{
202	if (!__kmem_cache_empty(cache))
203		quarantine_remove_cache(cache);
204}
205
206static void register_global(struct kasan_global *global)
207{
208	size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
209
210	kasan_unpoison_shadow(global->beg, global->size);
211
212	kasan_poison_shadow(global->beg + aligned_size,
213		global->size_with_redzone - aligned_size,
214		KASAN_GLOBAL_REDZONE);
215}
216
217void __asan_register_globals(struct kasan_global *globals, size_t size)
218{
219	int i;
220
221	for (i = 0; i < size; i++)
222		register_global(&globals[i]);
223}
224EXPORT_SYMBOL(__asan_register_globals);
225
226void __asan_unregister_globals(struct kasan_global *globals, size_t size)
227{
228}
229EXPORT_SYMBOL(__asan_unregister_globals);
230
231#define DEFINE_ASAN_LOAD_STORE(size)					\
232	void __asan_load##size(unsigned long addr)			\
233	{								\
234		check_memory_region_inline(addr, size, false, _RET_IP_);\
235	}								\
236	EXPORT_SYMBOL(__asan_load##size);				\
237	__alias(__asan_load##size)					\
238	void __asan_load##size##_noabort(unsigned long);		\
239	EXPORT_SYMBOL(__asan_load##size##_noabort);			\
240	void __asan_store##size(unsigned long addr)			\
241	{								\
242		check_memory_region_inline(addr, size, true, _RET_IP_);	\
243	}								\
244	EXPORT_SYMBOL(__asan_store##size);				\
245	__alias(__asan_store##size)					\
246	void __asan_store##size##_noabort(unsigned long);		\
247	EXPORT_SYMBOL(__asan_store##size##_noabort)
248
249DEFINE_ASAN_LOAD_STORE(1);
250DEFINE_ASAN_LOAD_STORE(2);
251DEFINE_ASAN_LOAD_STORE(4);
252DEFINE_ASAN_LOAD_STORE(8);
253DEFINE_ASAN_LOAD_STORE(16);
254
255void __asan_loadN(unsigned long addr, size_t size)
256{
257	check_memory_region(addr, size, false, _RET_IP_);
258}
259EXPORT_SYMBOL(__asan_loadN);
260
261__alias(__asan_loadN)
262void __asan_loadN_noabort(unsigned long, size_t);
263EXPORT_SYMBOL(__asan_loadN_noabort);
264
265void __asan_storeN(unsigned long addr, size_t size)
266{
267	check_memory_region(addr, size, true, _RET_IP_);
268}
269EXPORT_SYMBOL(__asan_storeN);
270
271__alias(__asan_storeN)
272void __asan_storeN_noabort(unsigned long, size_t);
273EXPORT_SYMBOL(__asan_storeN_noabort);
274
275/* to shut up compiler complaints */
276void __asan_handle_no_return(void) {}
277EXPORT_SYMBOL(__asan_handle_no_return);
278
279/* Emitted by compiler to poison alloca()ed objects. */
280void __asan_alloca_poison(unsigned long addr, size_t size)
281{
282	size_t rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
283	size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -
284			rounded_up_size;
285	size_t rounded_down_size = round_down(size, KASAN_SHADOW_SCALE_SIZE);
286
287	const void *left_redzone = (const void *)(addr -
288			KASAN_ALLOCA_REDZONE_SIZE);
289	const void *right_redzone = (const void *)(addr + rounded_up_size);
290
291	WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE));
292
293	kasan_unpoison_shadow((const void *)(addr + rounded_down_size),
294			      size - rounded_down_size);
295	kasan_poison_shadow(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
296			KASAN_ALLOCA_LEFT);
297	kasan_poison_shadow(right_redzone,
298			padding_size + KASAN_ALLOCA_REDZONE_SIZE,
299			KASAN_ALLOCA_RIGHT);
300}
301EXPORT_SYMBOL(__asan_alloca_poison);
302
303/* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */
304void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
305{
306	if (unlikely(!stack_top || stack_top > stack_bottom))
307		return;
308
309	kasan_unpoison_shadow(stack_top, stack_bottom - stack_top);
310}
311EXPORT_SYMBOL(__asan_allocas_unpoison);
312
313/* Emitted by the compiler to [un]poison local variables. */
314#define DEFINE_ASAN_SET_SHADOW(byte) \
315	void __asan_set_shadow_##byte(const void *addr, size_t size)	\
316	{								\
317		__memset((void *)addr, 0x##byte, size);			\
318	}								\
319	EXPORT_SYMBOL(__asan_set_shadow_##byte)
320
321DEFINE_ASAN_SET_SHADOW(00);
322DEFINE_ASAN_SET_SHADOW(f1);
323DEFINE_ASAN_SET_SHADOW(f2);
324DEFINE_ASAN_SET_SHADOW(f3);
325DEFINE_ASAN_SET_SHADOW(f5);
326DEFINE_ASAN_SET_SHADOW(f8);

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * This file contains core generic KASAN code.
  4 *
  5 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
  6 * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
  7 *
  8 * Some code borrowed from https://github.com/xairy/kasan-prototype by
  9 *        Andrey Konovalov <andreyknvl@gmail.com>
 10 *
 11 * This program is free software; you can redistribute it and/or modify
 12 * it under the terms of the GNU General Public License version 2 as
 13 * published by the Free Software Foundation.
 14 *
 15 */
 16
 17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 18
 19#include <linux/export.h>
 20#include <linux/interrupt.h>
 21#include <linux/init.h>
 22#include <linux/kasan.h>
 23#include <linux/kernel.h>
 24#include <linux/kmemleak.h>
 25#include <linux/linkage.h>
 26#include <linux/memblock.h>
 27#include <linux/memory.h>
 28#include <linux/mm.h>
 29#include <linux/module.h>
 30#include <linux/printk.h>
 31#include <linux/sched.h>
 32#include <linux/sched/task_stack.h>
 33#include <linux/slab.h>
 34#include <linux/stacktrace.h>
 35#include <linux/string.h>
 36#include <linux/types.h>
 37#include <linux/vmalloc.h>
 38#include <linux/bug.h>
 39
 40#include "kasan.h"
 41#include "../slab.h"
 42
 43/*
 44 * All functions below always inlined so compiler could
 45 * perform better optimizations in each of __asan_loadX/__assn_storeX
 46 * depending on memory access size X.
 47 */
 48
 49static __always_inline bool memory_is_poisoned_1(unsigned long addr)
 50{
 51	s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
 52
 53	if (unlikely(shadow_value)) {
 54		s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
 55		return unlikely(last_accessible_byte >= shadow_value);
 56	}
 57
 58	return false;
 59}
 60
 61static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr,
 62						unsigned long size)
 63{
 64	u8 *shadow_addr = (u8 *)kasan_mem_to_shadow((void *)addr);
 65
 66	/*
 67	 * Access crosses 8(shadow size)-byte boundary. Such access maps
 68	 * into 2 shadow bytes, so we need to check them both.
 69	 */
 70	if (unlikely(((addr + size - 1) & KASAN_SHADOW_MASK) < size - 1))
 71		return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
 72
 73	return memory_is_poisoned_1(addr + size - 1);
 74}
 75
 76static __always_inline bool memory_is_poisoned_16(unsigned long addr)
 77{
 78	u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 79
 80	/* Unaligned 16-bytes access maps into 3 shadow bytes. */
 81	if (unlikely(!IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 82		return *shadow_addr || memory_is_poisoned_1(addr + 15);
 83
 84	return *shadow_addr;
 85}
 86
 87static __always_inline unsigned long bytes_is_nonzero(const u8 *start,
 88					size_t size)
 89{
 90	while (size) {
 91		if (unlikely(*start))
 92			return (unsigned long)start;
 93		start++;
 94		size--;
 95	}
 96
 97	return 0;
 98}
 99
100static __always_inline unsigned long memory_is_nonzero(const void *start,
101						const void *end)
102{
103	unsigned int words;
104	unsigned long ret;
105	unsigned int prefix = (unsigned long)start % 8;
106
107	if (end - start <= 16)
108		return bytes_is_nonzero(start, end - start);
109
110	if (prefix) {
111		prefix = 8 - prefix;
112		ret = bytes_is_nonzero(start, prefix);
113		if (unlikely(ret))
114			return ret;
115		start += prefix;
116	}
117
118	words = (end - start) / 8;
119	while (words) {
120		if (unlikely(*(u64 *)start))
121			return bytes_is_nonzero(start, 8);
122		start += 8;
123		words--;
124	}
125
126	return bytes_is_nonzero(start, (end - start) % 8);
127}
128
129static __always_inline bool memory_is_poisoned_n(unsigned long addr,
130						size_t size)
131{
132	unsigned long ret;
133
134	ret = memory_is_nonzero(kasan_mem_to_shadow((void *)addr),
135			kasan_mem_to_shadow((void *)addr + size - 1) + 1);
136
137	if (unlikely(ret)) {
138		unsigned long last_byte = addr + size - 1;
139		s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
140
141		if (unlikely(ret != (unsigned long)last_shadow ||
142			((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
143			return true;
144	}
145	return false;
146}
147
148static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
149{
150	if (__builtin_constant_p(size)) {
151		switch (size) {
152		case 1:
153			return memory_is_poisoned_1(addr);
154		case 2:
155		case 4:
156		case 8:
157			return memory_is_poisoned_2_4_8(addr, size);
158		case 16:
159			return memory_is_poisoned_16(addr);
160		default:
161			BUILD_BUG();
162		}
163	}
164
165	return memory_is_poisoned_n(addr, size);
166}
167
168static __always_inline bool check_memory_region_inline(unsigned long addr,
169						size_t size, bool write,
170						unsigned long ret_ip)
171{
172	if (unlikely(size == 0))
173		return true;
174
175	if (unlikely(addr + size < addr))
176		return !kasan_report(addr, size, write, ret_ip);
177
178	if (unlikely((void *)addr <
179		kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
180		return !kasan_report(addr, size, write, ret_ip);
 
181	}
182
183	if (likely(!memory_is_poisoned(addr, size)))
184		return true;
185
186	return !kasan_report(addr, size, write, ret_ip);
 
187}
188
189bool check_memory_region(unsigned long addr, size_t size, bool write,
190				unsigned long ret_ip)
191{
192	return check_memory_region_inline(addr, size, write, ret_ip);
193}
194
195void kasan_cache_shrink(struct kmem_cache *cache)
196{
197	quarantine_remove_cache(cache);
198}
199
200void kasan_cache_shutdown(struct kmem_cache *cache)
201{
202	if (!__kmem_cache_empty(cache))
203		quarantine_remove_cache(cache);
204}
205
206static void register_global(struct kasan_global *global)
207{
208	size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
209
210	kasan_unpoison_shadow(global->beg, global->size);
211
212	kasan_poison_shadow(global->beg + aligned_size,
213		global->size_with_redzone - aligned_size,
214		KASAN_GLOBAL_REDZONE);
215}
216
217void __asan_register_globals(struct kasan_global *globals, size_t size)
218{
219	int i;
220
221	for (i = 0; i < size; i++)
222		register_global(&globals[i]);
223}
224EXPORT_SYMBOL(__asan_register_globals);
225
226void __asan_unregister_globals(struct kasan_global *globals, size_t size)
227{
228}
229EXPORT_SYMBOL(__asan_unregister_globals);
230
231#define DEFINE_ASAN_LOAD_STORE(size)					\
232	void __asan_load##size(unsigned long addr)			\
233	{								\
234		check_memory_region_inline(addr, size, false, _RET_IP_);\
235	}								\
236	EXPORT_SYMBOL(__asan_load##size);				\
237	__alias(__asan_load##size)					\
238	void __asan_load##size##_noabort(unsigned long);		\
239	EXPORT_SYMBOL(__asan_load##size##_noabort);			\
240	void __asan_store##size(unsigned long addr)			\
241	{								\
242		check_memory_region_inline(addr, size, true, _RET_IP_);	\
243	}								\
244	EXPORT_SYMBOL(__asan_store##size);				\
245	__alias(__asan_store##size)					\
246	void __asan_store##size##_noabort(unsigned long);		\
247	EXPORT_SYMBOL(__asan_store##size##_noabort)
248
249DEFINE_ASAN_LOAD_STORE(1);
250DEFINE_ASAN_LOAD_STORE(2);
251DEFINE_ASAN_LOAD_STORE(4);
252DEFINE_ASAN_LOAD_STORE(8);
253DEFINE_ASAN_LOAD_STORE(16);
254
255void __asan_loadN(unsigned long addr, size_t size)
256{
257	check_memory_region(addr, size, false, _RET_IP_);
258}
259EXPORT_SYMBOL(__asan_loadN);
260
261__alias(__asan_loadN)
262void __asan_loadN_noabort(unsigned long, size_t);
263EXPORT_SYMBOL(__asan_loadN_noabort);
264
265void __asan_storeN(unsigned long addr, size_t size)
266{
267	check_memory_region(addr, size, true, _RET_IP_);
268}
269EXPORT_SYMBOL(__asan_storeN);
270
271__alias(__asan_storeN)
272void __asan_storeN_noabort(unsigned long, size_t);
273EXPORT_SYMBOL(__asan_storeN_noabort);
274
275/* to shut up compiler complaints */
276void __asan_handle_no_return(void) {}
277EXPORT_SYMBOL(__asan_handle_no_return);
278
279/* Emitted by compiler to poison alloca()ed objects. */
280void __asan_alloca_poison(unsigned long addr, size_t size)
281{
282	size_t rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
283	size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -
284			rounded_up_size;
285	size_t rounded_down_size = round_down(size, KASAN_SHADOW_SCALE_SIZE);
286
287	const void *left_redzone = (const void *)(addr -
288			KASAN_ALLOCA_REDZONE_SIZE);
289	const void *right_redzone = (const void *)(addr + rounded_up_size);
290
291	WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE));
292
293	kasan_unpoison_shadow((const void *)(addr + rounded_down_size),
294			      size - rounded_down_size);
295	kasan_poison_shadow(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
296			KASAN_ALLOCA_LEFT);
297	kasan_poison_shadow(right_redzone,
298			padding_size + KASAN_ALLOCA_REDZONE_SIZE,
299			KASAN_ALLOCA_RIGHT);
300}
301EXPORT_SYMBOL(__asan_alloca_poison);
302
303/* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */
304void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
305{
306	if (unlikely(!stack_top || stack_top > stack_bottom))
307		return;
308
309	kasan_unpoison_shadow(stack_top, stack_bottom - stack_top);
310}
311EXPORT_SYMBOL(__asan_allocas_unpoison);
312
313/* Emitted by the compiler to [un]poison local variables. */
314#define DEFINE_ASAN_SET_SHADOW(byte) \
315	void __asan_set_shadow_##byte(const void *addr, size_t size)	\
316	{								\
317		__memset((void *)addr, 0x##byte, size);			\
318	}								\
319	EXPORT_SYMBOL(__asan_set_shadow_##byte)
320
321DEFINE_ASAN_SET_SHADOW(00);
322DEFINE_ASAN_SET_SHADOW(f1);
323DEFINE_ASAN_SET_SHADOW(f2);
324DEFINE_ASAN_SET_SHADOW(f3);
325DEFINE_ASAN_SET_SHADOW(f5);
326DEFINE_ASAN_SET_SHADOW(f8);
327
328void kasan_record_aux_stack(void *addr)
329{
330	struct page *page = kasan_addr_to_page(addr);
331	struct kmem_cache *cache;
332	struct kasan_alloc_meta *alloc_info;
333	void *object;
334
335	if (!(page && PageSlab(page)))
336		return;
337
338	cache = page->slab_cache;
339	object = nearest_obj(cache, page, addr);
340	alloc_info = get_alloc_info(cache, object);
341
342	/*
343	 * record the last two call_rcu() call stacks.
344	 */
345	alloc_info->aux_stack[1] = alloc_info->aux_stack[0];
346	alloc_info->aux_stack[0] = kasan_save_stack(GFP_NOWAIT);
347}
348
349void kasan_set_free_info(struct kmem_cache *cache,
350				void *object, u8 tag)
351{
352	struct kasan_free_meta *free_meta;
353
354	free_meta = get_free_info(cache, object);
355	kasan_set_track(&free_meta->free_track, GFP_NOWAIT);
356
357	/*
358	 *  the object was freed and has free track set
359	 */
360	*(u8 *)kasan_mem_to_shadow(object) = KASAN_KMALLOC_FREETRACK;
361}
362
363struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
364				void *object, u8 tag)
365{
366	if (*(u8 *)kasan_mem_to_shadow(object) != KASAN_KMALLOC_FREETRACK)
367		return NULL;
368	return &get_free_info(cache, object)->free_track;
369}