kunit/fortify: Add back "volatile" for sizeof() constants

It seems the Clang can see through OPTIMIZER_HIDE_VAR when the constant
is coming from sizeof. Adding "volatile" back to these variables solves
this false positive without reintroducing the issues that originally led
to switching to OPTIMIZER_HIDE_VAR in the first place[1].

Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://github.com/ClangBuiltLinux/linux/issues/2075 [1]
Cc: Jannik Glückert <jannik.glueckert@gmail.com>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Fixes: 6ee149f61b ("kunit/fortify: Replace "volatile" with OPTIMIZER_HIDE_VAR()")
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250628234034.work.800-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
This commit is contained in:
Kees Cook 2025-06-28 16:40:38 -07:00
parent 5e54510a93
commit 10299c07c9

View File

@ -1003,8 +1003,8 @@ static void fortify_test_memcmp(struct kunit *test)
{
char one[] = "My mind is going ...";
char two[] = "My mind is going ... I can feel it.";
size_t one_len = sizeof(one) - 1;
size_t two_len = sizeof(two) - 1;
volatile size_t one_len = sizeof(one) - 1;
volatile size_t two_len = sizeof(two) - 1;
OPTIMIZER_HIDE_VAR(one_len);
OPTIMIZER_HIDE_VAR(two_len);