6.15-stable review patch. If anyone has any objections, please let me know.
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From: Kees Cook kees@kernel.org
[ Upstream commit 10299c07c94aa0997fa43523b53301e713a6415d ]
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: 6ee149f61bcc ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- lib/tests/fortify_kunit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/tests/fortify_kunit.c b/lib/tests/fortify_kunit.c index 29ffc62a71e3..fc9c76f026d6 100644 --- a/lib/tests/fortify_kunit.c +++ b/lib/tests/fortify_kunit.c @@ -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);