lib/Kconfig.ubsan: Remove 'default UBSAN' from UBSAN_INTEGER_WRAP

commit cdc2e1d9d929d7f7009b3a5edca52388a2b0891f upstream.

CONFIG_UBSAN_INTEGER_WRAP is 'default UBSAN', which is problematic for a
couple of reasons.

The first is that this sanitizer is under active development on the
compiler side to come up with a solution that is maintainable on the
compiler side and usable on the kernel side. As a result of this, there
are many warnings when the sanitizer is enabled that have no clear path
to resolution yet but users may see them and report them in the meantime.

The second is that this option was renamed from
CONFIG_UBSAN_SIGNED_WRAP, meaning that if a configuration has
CONFIG_UBSAN=y but CONFIG_UBSAN_SIGNED_WRAP=n and it is upgraded via
olddefconfig (common in non-interactive scenarios such as CI),
CONFIG_UBSAN_INTEGER_WRAP will be silently enabled again.

Remove 'default UBSAN' from CONFIG_UBSAN_INTEGER_WRAP until it is ready
for regular usage and testing from a broader community than the folks
actively working on the feature.

Cc: stable@vger.kernel.org
Fixes: 557f8c582a9b ("ubsan: Reintroduce signed overflow sanitizer")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250414-drop-default-ubsan-integer-wrap-v1-1-392522551d6b@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
[nathan: Fix conflict due to lack of rename from ed2b548f1017 in stable]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index 1d4aa7a83b3a55ee9fc3612ceb1c1f157c2dafb7..37655f58b8554e764e48b7dd8b379bbd4402944b 100644 (file)
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -118,7 +118,6 @@ config UBSAN_UNREACHABLE
 
 config UBSAN_SIGNED_WRAP
        bool "Perform checking for signed arithmetic wrap-around"
-       default UBSAN
        depends on !COMPILE_TEST
        # The no_sanitize attribute was introduced in GCC with version 8.
        depends on !CC_IS_GCC || GCC_VERSION >= 80000