From: Arnd Bergmann <arnd@xxxxxxxx> commit fb646a4cd3f0ff27d19911bef7b6622263723df6 upstream. The kasan sw-tags implementation contains one function that is only called from assembler and has no prototype in a header. This causes a W=1 warning: mm/kasan/sw_tags.c:171:6: warning: no previous prototype for 'kasan_tag_mismatch' [-Wmissing-prototypes] 171 | void kasan_tag_mismatch(unsigned long addr, unsigned long access_info, Add a prototype in the local header to get a clean build. Link: https://lkml.kernel.org/r/20230509145735.9263-1-arnd@xxxxxxxxxx Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx> Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/kasan/kasan.h | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -646,4 +646,7 @@ void *__hwasan_memset(void *addr, int c, void *__hwasan_memmove(void *dest, const void *src, size_t len); void *__hwasan_memcpy(void *dest, const void *src, size_t len); +void kasan_tag_mismatch(unsigned long addr, unsigned long access_info, + unsigned long ret_ip); + #endif /* __MM_KASAN_KASAN_H */