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kcsan: Instrument memcpy/memset/memmove with newer Clang 

With Clang version 16+, -fsanitize=thread will turn
memcpy/memset/memmove calls in instrumented functions into
__tsan_memcpy/__tsan_memset/__tsan_memmove calls respectively.

Add these functions to the core KCSAN runtime, so that we (a) catch data
races with mem* functions, and (b) won't run into linker errors with
such newer compilers.

Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Marco Elver 2022-09-12 11:45:40 +02:00 committed by Paul E. McKenney
parent 9abf2313ad
commit 7c201739be
1 changed files with 50 additions and 0 deletions
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50
kernel/kcsan/core.c
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@ -14,10 +14,12 @@
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/minmax.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/preempt.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include "encoding.h"
@ -1308,3 +1310,51 @@ noinline void __tsan_atomic_signal_fence(int memorder)
}
}
EXPORT_SYMBOL(__tsan_atomic_signal_fence);
#ifdef __HAVE_ARCH_MEMSET
void *__tsan_memset(void *s, int c, size_t count);
noinline void *__tsan_memset(void *s, int c, size_t count)
{
/*
* Instead of not setting up watchpoints where accessed size is greater
* than MAX_ENCODABLE_SIZE, truncate checked size to MAX_ENCODABLE_SIZE.
*/
size_t check_len = min_t(size_t, count, MAX_ENCODABLE_SIZE);
check_access(s, check_len, KCSAN_ACCESS_WRITE, _RET_IP_);
return memset(s, c, count);
}
#else
void *__tsan_memset(void *s, int c, size_t count) __alias(memset);
#endif
EXPORT_SYMBOL(__tsan_memset);
#ifdef __HAVE_ARCH_MEMMOVE
void *__tsan_memmove(void *dst, const void *src, size_t len);
noinline void *__tsan_memmove(void *dst, const void *src, size_t len)
{
size_t check_len = min_t(size_t, len, MAX_ENCODABLE_SIZE);
check_access(dst, check_len, KCSAN_ACCESS_WRITE, _RET_IP_);
check_access(src, check_len, 0, _RET_IP_);
return memmove(dst, src, len);
}
#else
void *__tsan_memmove(void *dst, const void *src, size_t len) __alias(memmove);
#endif
EXPORT_SYMBOL(__tsan_memmove);
#ifdef __HAVE_ARCH_MEMCPY
void *__tsan_memcpy(void *dst, const void *src, size_t len);
noinline void *__tsan_memcpy(void *dst, const void *src, size_t len)
{
size_t check_len = min_t(size_t, len, MAX_ENCODABLE_SIZE);
check_access(dst, check_len, KCSAN_ACCESS_WRITE, _RET_IP_);
check_access(src, check_len, 0, _RET_IP_);
return memcpy(dst, src, len);
}
#else
void *__tsan_memcpy(void *dst, const void *src, size_t len) __alias(memcpy);
#endif
EXPORT_SYMBOL(__tsan_memcpy);