From: Martin Liska <mliska@xxxxxxx>
gcc doesn't always recognize that memcpy/set/move called through
__builtins are referenced because the reference happens too late in the
RTL expansion phase. This can make LTO to drop them, leading to
undefined symbols. Mark them as __used to avoid that.
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Martin Liska <mliska@xxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
mm/kasan/shadow.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index 0e3648b603a6..94c98feea9c8 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -39,7 +39,7 @@ bool __kasan_check_write(const volatile void *p, unsigned int size)
EXPORT_SYMBOL(__kasan_check_write);
#undef memset
-void *memset(void *addr, int c, size_t len)
+__used void *memset(void *addr, int c, size_t len)
{
if (!kasan_check_range((unsigned long)addr, len, true, _RET_IP_))
return NULL;
@@ -49,7 +49,7 @@ void *memset(void *addr, int c, size_t len)
#ifdef __HAVE_ARCH_MEMMOVE
#undef memmove
-void *memmove(void *dest, const void *src, size_t len)
+__used void *memmove(void *dest, const void *src, size_t len)
{
if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) ||
!kasan_check_range((unsigned long)dest, len, true, _RET_IP_))
@@ -60,7 +60,7 @@ void *memmove(void *dest, const void *src, size_t len)
#endif
#undef memcpy
-void *memcpy(void *dest, const void *src, size_t len)
+__used void *memcpy(void *dest, const void *src, size_t len)
{
if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) ||
!kasan_check_range((unsigned long)dest, len, true, _RET_IP_))
--
2.38.1
