From nobody Mon Feb 9 14:00:54 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 583112571D4; Thu, 23 Oct 2025 19:01:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761246100; cv=none; b=qXuJgASUS+T7yoFk91zQRjm359D/2XvSLW+B0YwfIT3+1NGGJojhPc/prJrEwTMPDBiI5T4TpGBp+a6DyTpVU+yDBgS/feS4lCL6l6YX1gTp8ad5vbiwYRB6U0/IfyB13Sq5trkYVNjU9BiKEGOM3L2hesfKZZheeBBaIIMTRNU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761246100; c=relaxed/simple; bh=Rl/OP3FUtJNNdUtSALnXRPKL3CMR9JuwjVxR8uU0OvA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=hdyNnbmEQIN02kgNe4wS1Qf8mkMbOIwhUyrMVp9Kj6oKr7F9tmZFAqKt5mP5GTkyQ7hQcl8/X6Ut8QmBiEx+lQ1Ec0+qni25ev6LCNrUNgDzUfn+QzJf6EcezRFnsHvhro00m4O09gJFFehGn9NbWqEWfO/QB1mEEGSv3dS0ubg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KdmDjyF4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KdmDjyF4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9F97C4CEE7; Thu, 23 Oct 2025 19:01:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761246099; bh=Rl/OP3FUtJNNdUtSALnXRPKL3CMR9JuwjVxR8uU0OvA=; h=From:Date:Subject:To:Cc:From; b=KdmDjyF4mvdZ/KlLwBcAWfYN+cmsezIappNMctorGGbd+64oe3Xbv2d8bFQf0w+Ca 7OxtqMf3GUxC1pvHSHD9HF/hg5KZMjK4hmL++1GSp665lcTl8kljxzYpsFxfREs+yU S5Uyd/fk63E4NkxE+wmeZXJUJpQYwMP29dHaRXf7MKNU5Z5jUcCL7Hguu2orA8gZhk ba3XYKBWlQM+mO8mJY6fJC5JD9rjpSnIOAWDGlGtzqb4VW4mBtWHiAfL/2dlnyQB++ INZS0sprULDtDZuJlt1lp2uN2p0GimKrQNv4J2qc7CGFidlu8nQXqbhh+z9vf7KEse EKd+MPjxvfo4A== From: Nathan Chancellor Date: Thu, 23 Oct 2025 21:01:29 +0200 Subject: [PATCH] KMSAN: Restore dynamic check for '-fsanitize=kernel-memory' Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251023-fix-kmsan-check-s390-clang-v1-1-4e6df477a4cc@kernel.org> X-B4-Tracking: v=1; b=H4sIAIh7+mgC/x3MTQqDQAxA4atI1gbmBynTqxQXGjM1TDvKBKQg3 r3B5YOPd4JyE1Z4dic0PkRlqxa+74DWqb4ZZbGG4MLgXYiY5Yflq1NFWpkKakwO6WMUfXJLfMw z5RzBBntj0/f8NV7XH/7mBb1sAAAA X-Change-ID: 20251023-fix-kmsan-check-s390-clang-190d37bbcff3 To: Alexander Potapenko , Marco Elver , Dmitry Vyukov Cc: Nicolas Schier , Kees Cook , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, kernel test robot , Nathan Chancellor X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=1869; i=nathan@kernel.org; h=from:subject:message-id; bh=Rl/OP3FUtJNNdUtSALnXRPKL3CMR9JuwjVxR8uU0OvA=; b=owGbwMvMwCUmm602sfCA1DTG02pJDBm/qiced1v7d/lK5Smz3a4c4Np8yvxnmv2BiNWeplO29 S3fdbaov6OUhUGMi0FWTJGl+rHqcUPDOWcZb5yaBDOHlQlkCAMXpwBM5PxpRoaT+72Ltly+qla7 +8WsD+m/dlx7eObXHXWJN7PuOvL89xUpZfifuvvo8lWik+0Kf687Kbsi4Gthn6lF+u3d5+ZWyW7 5fMuHHQA= X-Developer-Key: i=nathan@kernel.org; a=openpgp; fpr=2437CB76E544CB6AB3D9DFD399739260CB6CB716 Commit 5ff8c11775c7 ("KMSAN: Remove tautological checks") changed CONFIG_HAVE_KMSAN_COMPILER from a dynamic check for '-fsanitize=3Dkernel-memory' to just being true for CONFIG_CC_IS_CLANG. This missed the fact that not all architectures supported '-fsanitize=3Dkernel-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=3Dkernel-memory' for targ= et 's390x-unknown-linux-gnu' Restore the cc-option check for '-fsanitize=3Dkernel-memory' to make sure the compiler target properly supports '-fsanitize=3Dkernel-memory'. The check for '-msan-disable-checks=3D1' 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/a3e56a8792ffaf3a3d3538736= e1042b8db45ab89 [1] Reported-by: kernel test robot Closes: https://lore.kernel.org/r/202510220236.AVuXXCYy-lkp@intel.com/ Signed-off-by: Nathan Chancellor Acked-by: Nicolas Schier --- I plan to take this via kbuild-fixes for 6.18-rc3 or -rc4. --- lib/Kconfig.kmsan | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan index 7251b6b59e69..cae1ddcc18e1 100644 --- a/lib/Kconfig.kmsan +++ b/lib/Kconfig.kmsan @@ -3,7 +3,7 @@ config HAVE_ARCH_KMSAN bool =20 config HAVE_KMSAN_COMPILER - def_bool CC_IS_CLANG + def_bool $(cc-option,-fsanitize=3Dkernel-memory) =20 config KMSAN bool "KMSAN: detector of uninitialized values use" --- base-commit: 211ddde0823f1442e4ad052a2f30f050145ccada change-id: 20251023-fix-kmsan-check-s390-clang-190d37bbcff3 Best regards, -- =20 Nathan Chancellor