On Wed, 7 Sept 2022 at 19:39, Marco Elver elver@google.com wrote:
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
kernel/kcsan/core.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c index fe12dfe254ec..66ef48aa86e0 100644 --- a/kernel/kcsan/core.c +++ b/kernel/kcsan/core.c @@ -18,6 +18,7 @@ #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 +1309,29 @@ noinline void __tsan_atomic_signal_fence(int memorder) } } EXPORT_SYMBOL(__tsan_atomic_signal_fence);
+void *__tsan_memset(void *s, int c, size_t count); +noinline void *__tsan_memset(void *s, int c, size_t count) +{
check_access(s, count, KCSAN_ACCESS_WRITE, _RET_IP_);return __memset(s, c, count);+} +EXPORT_SYMBOL(__tsan_memset);
+void *__tsan_memmove(void *dst, const void *src, size_t len); +noinline void *__tsan_memmove(void *dst, const void *src, size_t len) +{
check_access(dst, len, KCSAN_ACCESS_WRITE, _RET_IP_);check_access(src, len, 0, _RET_IP_);return __memmove(dst, src, len);+} +EXPORT_SYMBOL(__tsan_memmove);
+void *__tsan_memcpy(void *dst, const void *src, size_t len); +noinline void *__tsan_memcpy(void *dst, const void *src, size_t len) +{
check_access(dst, len, KCSAN_ACCESS_WRITE, _RET_IP_);check_access(src, len, 0, _RET_IP_);return __memcpy(dst, src, len);+} +EXPORT_SYMBOL(__tsan_memcpy);
I missed that s390 doesn't have arch memcpy variants, so this fails:
kernel/kcsan/core.c:1316:16: error: implicit declaration of function '__memset'; did you mean '__memset64'? [-Werror=implicit-function-declaration]
I'll send a v2 where __tsan_mem* is aliased to generic versions if the arch doesn't have mem*() functions.
-- 2.37.2.789.g6183377224-goog