Use a volatile pointer to write outside the buffer so the compiler can't optimize it away.

Reported-by: Alexey Dobriyan adobriyan@gmail.com Link: https://lore.kernel.org/lkml/c0584807-511c-4496-b062-1263ea38f349@p183/ Signed-off-by: Thomas Weißschuh linux@weissschuh.net ---

This is based on the "dev" branch of the rcu tree. --- tools/testing/selftests/nolibc/nolibc-test.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 21bacc928bf7..47013b78972e 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -667,17 +667,13 @@ int run_stdlib(int min, int max) return ret; }

-#if defined(__clang__) -__attribute__((optnone)) -#elif defined(__GNUC__) -__attribute__((optimize("O0"))) -#endif static int smash_stack(void) { char buf[100]; + volatile char *ptr = buf;

for (size_t i = 0; i < 200; i++) - buf[i] = 'P'; + ptr[i] = 'P';

return 1; }

--- base-commit: 6e7cac3d5b8c77ddedfaa7efad23aa542cde53b2 change-id: 20230328-nolibc-smash-stack-volatile-0e87e9273fea

Best regards,