From cf20852500d2895d1db22b69d87281aca2e7b5d0 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 23 Oct 2025 21:01:29 +0200 Subject: [PATCH] KMSAN: Restore dynamic check for '-fsanitize=kernel-memory' Commit 5ff8c11775c7 ("KMSAN: Remove tautological checks") changed CONFIG_HAVE_KMSAN_COMPILER from a dynamic check for '-fsanitize=kernel-memory' to just being true for CONFIG_CC_IS_CLANG. This missed the fact that not all architectures supported '-fsanitize=kernel-memory' at the same time. For example, SystemZ / s390 gained support for KMSAN in clang-18 [1], so builds with clang-15 through clang-17 can select KMSAN but they error with: clang-16: error: unsupported option '-fsanitize=kernel-memory' for target 's390x-unknown-linux-gnu' Restore the cc-option check for '-fsanitize=kernel-memory' to make sure the compiler target properly supports '-fsanitize=kernel-memory'. The check for '-msan-disable-checks=1' does not need to be restored because all supported clang versions for building the kernel support it. Fixes: 5ff8c11775c7 ("KMSAN: Remove tautological checks") Link: https://github.com/llvm/llvm-project/commit/a3e56a8792ffaf3a3d3538736e1042b8db45ab89 [1] Reported-by: kernel test robot Closes: https://lore.kernel.org/r/202510220236.AVuXXCYy-lkp@intel.com/ Acked-by: Nicolas Schier Link: https://patch.msgid.link/20251023-fix-kmsan-check-s390-clang-v1-1-4e6df477a4cc@kernel.org Signed-off-by: Nathan Chancellor --- lib/Kconfig.kmsan | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan index 7251b6b59e693..cae1ddcc18e15 100644 --- a/lib/Kconfig.kmsan +++ b/lib/Kconfig.kmsan @@ -3,7 +3,7 @@ config HAVE_ARCH_KMSAN bool config HAVE_KMSAN_COMPILER - def_bool CC_IS_CLANG + def_bool $(cc-option,-fsanitize=kernel-memory) config KMSAN bool "KMSAN: detector of uninitialized values use" -- 2.47.3