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authorAndrey Ryabinin <a.ryabinin@samsung.com>2015-02-13 22:39:17 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-14 05:21:40 (GMT)
commit0b24becc810dc3be6e3f94103a866f214c282394 (patch)
treead4ca40742a383f4b9e7385cc7f2506eee1aa24b /mm
parentcb4188ac8e5779f66b9f55888ac2c75b391cde44 (diff)
kasan: add kernel address sanitizer infrastructure
Kernel Address sanitizer (KASan) is a dynamic memory error detector. It provides fast and comprehensive solution for finding use-after-free and out-of-bounds bugs. KASAN uses compile-time instrumentation for checking every memory access, therefore GCC > v4.9.2 required. v4.9.2 almost works, but has issues with putting symbol aliases into the wrong section, which breaks kasan instrumentation of globals. This patch only adds infrastructure for kernel address sanitizer. It's not available for use yet. The idea and some code was borrowed from [1]. Basic idea: The main idea of KASAN is to use shadow memory to record whether each byte of memory is safe to access or not, and use compiler's instrumentation to check the shadow memory on each memory access. Address sanitizer uses 1/8 of the memory addressable in kernel for shadow memory and uses direct mapping with a scale and offset to translate a memory address to its corresponding shadow address. Here is function to translate address to corresponding shadow address: unsigned long kasan_mem_to_shadow(unsigned long addr) { return (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET; } where KASAN_SHADOW_SCALE_SHIFT = 3. So for every 8 bytes there is one corresponding byte of shadow memory. The following encoding used for each shadow byte: 0 means that all 8 bytes of the corresponding memory region are valid for access; k (1 <= k <= 7) means that the first k bytes are valid for access, and other (8 - k) bytes are not; Any negative value indicates that the entire 8-bytes are inaccessible. Different negative values used to distinguish between different kinds of inaccessible memory (redzones, freed memory) (see mm/kasan/kasan.h). To be able to detect accesses to bad memory we need a special compiler. Such compiler inserts a specific function calls (__asan_load*(addr), __asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16. These functions check whether memory region is valid to access or not by checking corresponding shadow memory. If access is not valid an error printed. Historical background of the address sanitizer from Dmitry Vyukov: "We've developed the set of tools, AddressSanitizer (Asan), ThreadSanitizer and MemorySanitizer, for user space. We actively use them for testing inside of Google (continuous testing, fuzzing, running prod services). To date the tools have found more than 10'000 scary bugs in Chromium, Google internal codebase and various open-source projects (Firefox, OpenSSL, gcc, clang, ffmpeg, MySQL and lots of others): [2] [3] [4]. The tools are part of both gcc and clang compilers. We have not yet done massive testing under the Kernel AddressSanitizer (it's kind of chicken and egg problem, you need it to be upstream to start applying it extensively). To date it has found about 50 bugs. Bugs that we've found in upstream kernel are listed in [5]. We've also found ~20 bugs in out internal version of the kernel. Also people from Samsung and Oracle have found some. [...] As others noted, the main feature of AddressSanitizer is its performance due to inline compiler instrumentation and simple linear shadow memory. User-space Asan has ~2x slowdown on computational programs and ~2x memory consumption increase. Taking into account that kernel usually consumes only small fraction of CPU and memory when running real user-space programs, I would expect that kernel Asan will have ~10-30% slowdown and similar memory consumption increase (when we finish all tuning). I agree that Asan can well replace kmemcheck. We have plans to start working on Kernel MemorySanitizer that finds uses of unitialized memory. Asan+Msan will provide feature-parity with kmemcheck. As others noted, Asan will unlikely replace debug slab and pagealloc that can be enabled at runtime. Asan uses compiler instrumentation, so even if it is disabled, it still incurs visible overheads. Asan technology is easily portable to other architectures. Compiler instrumentation is fully portable. Runtime has some arch-dependent parts like shadow mapping and atomic operation interception. They are relatively easy to port." Comparison with other debugging features: ======================================== KMEMCHECK: - KASan can do almost everything that kmemcheck can. KASan uses compile-time instrumentation, which makes it significantly faster than kmemcheck. The only advantage of kmemcheck over KASan is detection of uninitialized memory reads. Some brief performance testing showed that kasan could be x500-x600 times faster than kmemcheck: $ netperf -l 30 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec no debug: 87380 16384 16384 30.00 41624.72 kasan inline: 87380 16384 16384 30.00 12870.54 kasan outline: 87380 16384 16384 30.00 10586.39 kmemcheck: 87380 16384 16384 30.03 20.23 - Also kmemcheck couldn't work on several CPUs. It always sets number of CPUs to 1. KASan doesn't have such limitation. DEBUG_PAGEALLOC: - KASan is slower than DEBUG_PAGEALLOC, but KASan works on sub-page granularity level, so it able to find more bugs. SLUB_DEBUG (poisoning, redzones): - SLUB_DEBUG has lower overhead than KASan. - SLUB_DEBUG in most cases are not able to detect bad reads, KASan able to detect both reads and writes. - In some cases (e.g. redzone overwritten) SLUB_DEBUG detect bugs only on allocation/freeing of object. KASan catch bugs right before it will happen, so we always know exact place of first bad read/write. [1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel [2] https://code.google.com/p/address-sanitizer/wiki/FoundBugs [3] https://code.google.com/p/thread-sanitizer/wiki/FoundBugs [4] https://code.google.com/p/memory-sanitizer/wiki/FoundBugs [5] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel#Trophies Based on work by Andrey Konovalov. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Acked-by: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/Makefile1
-rw-r--r--mm/kasan/Makefile8
-rw-r--r--mm/kasan/kasan.c302
-rw-r--r--mm/kasan/kasan.h34
-rw-r--r--mm/kasan/report.c209
5 files changed, 554 insertions, 0 deletions
diff --git a/mm/Makefile b/mm/Makefile
index 3548460..930b52d 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_PAGE_POISONING) += debug-pagealloc.o
obj-$(CONFIG_SLAB) += slab.o
obj-$(CONFIG_SLUB) += slub.o
obj-$(CONFIG_KMEMCHECK) += kmemcheck.o
+obj-$(CONFIG_KASAN) += kasan/
obj-$(CONFIG_FAILSLAB) += failslab.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
obj-$(CONFIG_FS_XIP) += filemap_xip.o
diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
new file mode 100644
index 0000000..bd837b8
--- /dev/null
+++ b/mm/kasan/Makefile
@@ -0,0 +1,8 @@
+KASAN_SANITIZE := n
+
+CFLAGS_REMOVE_kasan.o = -pg
+# Function splitter causes unnecessary splits in __asan_load1/__asan_store1
+# see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533
+CFLAGS_kasan.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
+
+obj-y := kasan.o report.o
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
new file mode 100644
index 0000000..6dc1aa7
--- /dev/null
+++ b/mm/kasan/kasan.c
@@ -0,0 +1,302 @@
+/*
+ * This file contains shadow memory manipulation code.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
+ *
+ * Some of code borrowed from https://github.com/xairy/linux by
+ * Andrey Konovalov <adech.fo@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#define DISABLE_BRANCH_PROFILING
+
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/memblock.h>
+#include <linux/mm.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/kasan.h>
+
+#include "kasan.h"
+
+/*
+ * Poisons the shadow memory for 'size' bytes starting from 'addr'.
+ * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
+ */
+static void kasan_poison_shadow(const void *address, size_t size, u8 value)
+{
+ void *shadow_start, *shadow_end;
+
+ shadow_start = kasan_mem_to_shadow(address);
+ shadow_end = kasan_mem_to_shadow(address + size);
+
+ memset(shadow_start, value, shadow_end - shadow_start);
+}
+
+void kasan_unpoison_shadow(const void *address, size_t size)
+{
+ kasan_poison_shadow(address, size, 0);
+
+ if (size & KASAN_SHADOW_MASK) {
+ u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
+ *shadow = size & KASAN_SHADOW_MASK;
+ }
+}
+
+
+/*
+ * All functions below always inlined so compiler could
+ * perform better optimizations in each of __asan_loadX/__assn_storeX
+ * depending on memory access size X.
+ */
+
+static __always_inline bool memory_is_poisoned_1(unsigned long addr)
+{
+ s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
+
+ if (unlikely(shadow_value)) {
+ s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
+ return unlikely(last_accessible_byte >= shadow_value);
+ }
+
+ return false;
+}
+
+static __always_inline bool memory_is_poisoned_2(unsigned long addr)
+{
+ u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
+
+ if (unlikely(*shadow_addr)) {
+ if (memory_is_poisoned_1(addr + 1))
+ return true;
+
+ if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
+ return false;
+
+ return unlikely(*(u8 *)shadow_addr);
+ }
+
+ return false;
+}
+
+static __always_inline bool memory_is_poisoned_4(unsigned long addr)
+{
+ u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
+
+ if (unlikely(*shadow_addr)) {
+ if (memory_is_poisoned_1(addr + 3))
+ return true;
+
+ if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
+ return false;
+
+ return unlikely(*(u8 *)shadow_addr);
+ }
+
+ return false;
+}
+
+static __always_inline bool memory_is_poisoned_8(unsigned long addr)
+{
+ u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
+
+ if (unlikely(*shadow_addr)) {
+ if (memory_is_poisoned_1(addr + 7))
+ return true;
+
+ if (likely(((addr + 7) & KASAN_SHADOW_MASK) >= 7))
+ return false;
+
+ return unlikely(*(u8 *)shadow_addr);
+ }
+
+ return false;
+}
+
+static __always_inline bool memory_is_poisoned_16(unsigned long addr)
+{
+ u32 *shadow_addr = (u32 *)kasan_mem_to_shadow((void *)addr);
+
+ if (unlikely(*shadow_addr)) {
+ u16 shadow_first_bytes = *(u16 *)shadow_addr;
+ s8 last_byte = (addr + 15) & KASAN_SHADOW_MASK;
+
+ if (unlikely(shadow_first_bytes))
+ return true;
+
+ if (likely(!last_byte))
+ return false;
+
+ return memory_is_poisoned_1(addr + 15);
+ }
+
+ return false;
+}
+
+static __always_inline unsigned long bytes_is_zero(const u8 *start,
+ size_t size)
+{
+ while (size) {
+ if (unlikely(*start))
+ return (unsigned long)start;
+ start++;
+ size--;
+ }
+
+ return 0;
+}
+
+static __always_inline unsigned long memory_is_zero(const void *start,
+ const void *end)
+{
+ unsigned int words;
+ unsigned long ret;
+ unsigned int prefix = (unsigned long)start % 8;
+
+ if (end - start <= 16)
+ return bytes_is_zero(start, end - start);
+
+ if (prefix) {
+ prefix = 8 - prefix;
+ ret = bytes_is_zero(start, prefix);
+ if (unlikely(ret))
+ return ret;
+ start += prefix;
+ }
+
+ words = (end - start) / 8;
+ while (words) {
+ if (unlikely(*(u64 *)start))
+ return bytes_is_zero(start, 8);
+ start += 8;
+ words--;
+ }
+
+ return bytes_is_zero(start, (end - start) % 8);
+}
+
+static __always_inline bool memory_is_poisoned_n(unsigned long addr,
+ size_t size)
+{
+ unsigned long ret;
+
+ ret = memory_is_zero(kasan_mem_to_shadow((void *)addr),
+ kasan_mem_to_shadow((void *)addr + size - 1) + 1);
+
+ if (unlikely(ret)) {
+ unsigned long last_byte = addr + size - 1;
+ s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
+
+ if (unlikely(ret != (unsigned long)last_shadow ||
+ ((last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
+ return true;
+ }
+ return false;
+}
+
+static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
+{
+ if (__builtin_constant_p(size)) {
+ switch (size) {
+ case 1:
+ return memory_is_poisoned_1(addr);
+ case 2:
+ return memory_is_poisoned_2(addr);
+ case 4:
+ return memory_is_poisoned_4(addr);
+ case 8:
+ return memory_is_poisoned_8(addr);
+ case 16:
+ return memory_is_poisoned_16(addr);
+ default:
+ BUILD_BUG();
+ }
+ }
+
+ return memory_is_poisoned_n(addr, size);
+}
+
+
+static __always_inline void check_memory_region(unsigned long addr,
+ size_t size, bool write)
+{
+ struct kasan_access_info info;
+
+ if (unlikely(size == 0))
+ return;
+
+ if (unlikely((void *)addr <
+ kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
+ info.access_addr = (void *)addr;
+ info.access_size = size;
+ info.is_write = write;
+ info.ip = _RET_IP_;
+ kasan_report_user_access(&info);
+ return;
+ }
+
+ if (likely(!memory_is_poisoned(addr, size)))
+ return;
+
+ kasan_report(addr, size, write, _RET_IP_);
+}
+
+#define DEFINE_ASAN_LOAD_STORE(size) \
+ void __asan_load##size(unsigned long addr) \
+ { \
+ check_memory_region(addr, size, false); \
+ } \
+ EXPORT_SYMBOL(__asan_load##size); \
+ __alias(__asan_load##size) \
+ void __asan_load##size##_noabort(unsigned long); \
+ EXPORT_SYMBOL(__asan_load##size##_noabort); \
+ void __asan_store##size(unsigned long addr) \
+ { \
+ check_memory_region(addr, size, true); \
+ } \
+ EXPORT_SYMBOL(__asan_store##size); \
+ __alias(__asan_store##size) \
+ void __asan_store##size##_noabort(unsigned long); \
+ EXPORT_SYMBOL(__asan_store##size##_noabort)
+
+DEFINE_ASAN_LOAD_STORE(1);
+DEFINE_ASAN_LOAD_STORE(2);
+DEFINE_ASAN_LOAD_STORE(4);
+DEFINE_ASAN_LOAD_STORE(8);
+DEFINE_ASAN_LOAD_STORE(16);
+
+void __asan_loadN(unsigned long addr, size_t size)
+{
+ check_memory_region(addr, size, false);
+}
+EXPORT_SYMBOL(__asan_loadN);
+
+__alias(__asan_loadN)
+void __asan_loadN_noabort(unsigned long, size_t);
+EXPORT_SYMBOL(__asan_loadN_noabort);
+
+void __asan_storeN(unsigned long addr, size_t size)
+{
+ check_memory_region(addr, size, true);
+}
+EXPORT_SYMBOL(__asan_storeN);
+
+__alias(__asan_storeN)
+void __asan_storeN_noabort(unsigned long, size_t);
+EXPORT_SYMBOL(__asan_storeN_noabort);
+
+/* to shut up compiler complaints */
+void __asan_handle_no_return(void) {}
+EXPORT_SYMBOL(__asan_handle_no_return);
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
new file mode 100644
index 0000000..648b9c0
--- /dev/null
+++ b/mm/kasan/kasan.h
@@ -0,0 +1,34 @@
+#ifndef __MM_KASAN_KASAN_H
+#define __MM_KASAN_KASAN_H
+
+#include <linux/kasan.h>
+
+#define KASAN_SHADOW_SCALE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT)
+#define KASAN_SHADOW_MASK (KASAN_SHADOW_SCALE_SIZE - 1)
+
+struct kasan_access_info {
+ const void *access_addr;
+ const void *first_bad_addr;
+ size_t access_size;
+ bool is_write;
+ unsigned long ip;
+};
+
+void kasan_report_error(struct kasan_access_info *info);
+void kasan_report_user_access(struct kasan_access_info *info);
+
+static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
+{
+ return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET)
+ << KASAN_SHADOW_SCALE_SHIFT);
+}
+
+static inline bool kasan_enabled(void)
+{
+ return !current->kasan_depth;
+}
+
+void kasan_report(unsigned long addr, size_t size,
+ bool is_write, unsigned long ip);
+
+#endif
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
new file mode 100644
index 0000000..5835d69
--- /dev/null
+++ b/mm/kasan/report.c
@@ -0,0 +1,209 @@
+/*
+ * This file contains error reporting code.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
+ *
+ * Some of code borrowed from https://github.com/xairy/linux by
+ * Andrey Konovalov <adech.fo@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/kasan.h>
+
+#include "kasan.h"
+
+/* Shadow layout customization. */
+#define SHADOW_BYTES_PER_BLOCK 1
+#define SHADOW_BLOCKS_PER_ROW 16
+#define SHADOW_BYTES_PER_ROW (SHADOW_BLOCKS_PER_ROW * SHADOW_BYTES_PER_BLOCK)
+#define SHADOW_ROWS_AROUND_ADDR 2
+
+static const void *find_first_bad_addr(const void *addr, size_t size)
+{
+ u8 shadow_val = *(u8 *)kasan_mem_to_shadow(addr);
+ const void *first_bad_addr = addr;
+
+ while (!shadow_val && first_bad_addr < addr + size) {
+ first_bad_addr += KASAN_SHADOW_SCALE_SIZE;
+ shadow_val = *(u8 *)kasan_mem_to_shadow(first_bad_addr);
+ }
+ return first_bad_addr;
+}
+
+static void print_error_description(struct kasan_access_info *info)
+{
+ const char *bug_type = "unknown crash";
+ u8 shadow_val;
+
+ info->first_bad_addr = find_first_bad_addr(info->access_addr,
+ info->access_size);
+
+ shadow_val = *(u8 *)kasan_mem_to_shadow(info->first_bad_addr);
+
+ switch (shadow_val) {
+ case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
+ bug_type = "out of bounds access";
+ break;
+ }
+
+ pr_err("BUG: KASan: %s in %pS at addr %p\n",
+ bug_type, (void *)info->ip,
+ info->access_addr);
+ pr_err("%s of size %zu by task %s/%d\n",
+ info->is_write ? "Write" : "Read",
+ info->access_size, current->comm, task_pid_nr(current));
+}
+
+static void print_address_description(struct kasan_access_info *info)
+{
+ dump_stack();
+}
+
+static bool row_is_guilty(const void *row, const void *guilty)
+{
+ return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW);
+}
+
+static int shadow_pointer_offset(const void *row, const void *shadow)
+{
+ /* The length of ">ff00ff00ff00ff00: " is
+ * 3 + (BITS_PER_LONG/8)*2 chars.
+ */
+ return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 +
+ (shadow - row) / SHADOW_BYTES_PER_BLOCK + 1;
+}
+
+static void print_shadow_for_address(const void *addr)
+{
+ int i;
+ const void *shadow = kasan_mem_to_shadow(addr);
+ const void *shadow_row;
+
+ shadow_row = (void *)round_down((unsigned long)shadow,
+ SHADOW_BYTES_PER_ROW)
+ - SHADOW_ROWS_AROUND_ADDR * SHADOW_BYTES_PER_ROW;
+
+ pr_err("Memory state around the buggy address:\n");
+
+ for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) {
+ const void *kaddr = kasan_shadow_to_mem(shadow_row);
+ char buffer[4 + (BITS_PER_LONG/8)*2];
+
+ snprintf(buffer, sizeof(buffer),
+ (i == 0) ? ">%p: " : " %p: ", kaddr);
+
+ kasan_disable_current();
+ print_hex_dump(KERN_ERR, buffer,
+ DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
+ shadow_row, SHADOW_BYTES_PER_ROW, 0);
+ kasan_enable_current();
+
+ if (row_is_guilty(shadow_row, shadow))
+ pr_err("%*c\n",
+ shadow_pointer_offset(shadow_row, shadow),
+ '^');
+
+ shadow_row += SHADOW_BYTES_PER_ROW;
+ }
+}
+
+static DEFINE_SPINLOCK(report_lock);
+
+void kasan_report_error(struct kasan_access_info *info)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&report_lock, flags);
+ pr_err("================================="
+ "=================================\n");
+ print_error_description(info);
+ print_address_description(info);
+ print_shadow_for_address(info->first_bad_addr);
+ pr_err("================================="
+ "=================================\n");
+ spin_unlock_irqrestore(&report_lock, flags);
+}
+
+void kasan_report_user_access(struct kasan_access_info *info)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&report_lock, flags);
+ pr_err("================================="
+ "=================================\n");
+ pr_err("BUG: KASan: user-memory-access on address %p\n",
+ info->access_addr);
+ pr_err("%s of size %zu by task %s/%d\n",
+ info->is_write ? "Write" : "Read",
+ info->access_size, current->comm, task_pid_nr(current));
+ dump_stack();
+ pr_err("================================="
+ "=================================\n");
+ spin_unlock_irqrestore(&report_lock, flags);
+}
+
+void kasan_report(unsigned long addr, size_t size,
+ bool is_write, unsigned long ip)
+{
+ struct kasan_access_info info;
+
+ if (likely(!kasan_enabled()))
+ return;
+
+ info.access_addr = (void *)addr;
+ info.access_size = size;
+ info.is_write = is_write;
+ info.ip = ip;
+ kasan_report_error(&info);
+}
+
+
+#define DEFINE_ASAN_REPORT_LOAD(size) \
+void __asan_report_load##size##_noabort(unsigned long addr) \
+{ \
+ kasan_report(addr, size, false, _RET_IP_); \
+} \
+EXPORT_SYMBOL(__asan_report_load##size##_noabort)
+
+#define DEFINE_ASAN_REPORT_STORE(size) \
+void __asan_report_store##size##_noabort(unsigned long addr) \
+{ \
+ kasan_report(addr, size, true, _RET_IP_); \
+} \
+EXPORT_SYMBOL(__asan_report_store##size##_noabort)
+
+DEFINE_ASAN_REPORT_LOAD(1);
+DEFINE_ASAN_REPORT_LOAD(2);
+DEFINE_ASAN_REPORT_LOAD(4);
+DEFINE_ASAN_REPORT_LOAD(8);
+DEFINE_ASAN_REPORT_LOAD(16);
+DEFINE_ASAN_REPORT_STORE(1);
+DEFINE_ASAN_REPORT_STORE(2);
+DEFINE_ASAN_REPORT_STORE(4);
+DEFINE_ASAN_REPORT_STORE(8);
+DEFINE_ASAN_REPORT_STORE(16);
+
+void __asan_report_load_n_noabort(unsigned long addr, size_t size)
+{
+ kasan_report(addr, size, false, _RET_IP_);
+}
+EXPORT_SYMBOL(__asan_report_load_n_noabort);
+
+void __asan_report_store_n_noabort(unsigned long addr, size_t size)
+{
+ kasan_report(addr, size, true, _RET_IP_);
+}
+EXPORT_SYMBOL(__asan_report_store_n_noabort);

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