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Date:   Wed,  2 Nov 2022 12:06:09 +0100
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Message-ID: <20221102110611.1085175-3-glider@google.com>
Subject: [PATCH 3/5] Kconfig.debug: ensure early check for KMSAN in CONFIG_KMSAN_WARN
From:   Alexander Potapenko <glider@google.com>
To:     glider@google.com
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        linux-kbuild@vger.kernel.org
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Precedence: bulk

As pointed out by Masahiro Yamada, Kconfig picks up the first default
entry which has true 'if' condition. Hence, the previously added check
for KMSAN was never used, because it followed the checks for 64BIT and
!64BIT.

Put KMSAN check before others to ensure it is always applied.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-kbuild@vger.kernel.org
Link: https://github.com/google/kmsan/issues/89
Link: https://lore.kernel.org/linux-mm/20221024212144.2852069-3-glider@google.com/
Fixes: 921757bc9b61 ("Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default")
Signed-off-by: Alexander Potapenko <glider@google.com>
---
 lib/Kconfig.debug | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 29280072dc0e4..b4a0988a7ffd2 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -395,12 +395,12 @@ endif # DEBUG_INFO
 config FRAME_WARN
 	int "Warn for stack frames larger than"
 	range 0 8192
+	default 0 if KMSAN
 	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
 	default 2048 if PARISC
 	default 1536 if (!64BIT && XTENSA)
 	default 1024 if !64BIT
 	default 2048 if 64BIT
-	default 0 if KMSAN
 	help
 	  Tell the compiler to warn at build time for stack frames larger than this.
 	  Setting this too low will cause a lot of warnings.
-- 
2.38.1.273.g43a17bfeac-goog