Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 24 Oct 2022 23:21:42 +0200
In-Reply-To: <20221024212144.2852069-1-glider@google.com>
Mime-Version: 1.0
References: <20221024212144.2852069-1-glider@google.com>
Message-ID: <20221024212144.2852069-3-glider@google.com>
Subject: [PATCH 3/5] Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default
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
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

KMSAN adds a lot of instrumentation to the code, which results in
increased stack usage (up to 2048 bytes and more in some cases).
It's hard to predict how big the stack frames can be, so we disable
the warnings for KMSAN instead.

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
Signed-off-by: Alexander Potapenko <glider@google.com>
---
 lib/Kconfig.debug | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 3fc7abffc7aa2..29280072dc0e4 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -400,8 +400,9 @@ config FRAME_WARN
 	default 1536 if (!64BIT && XTENSA)
 	default 1024 if !64BIT
 	default 2048 if 64BIT
+	default 0 if KMSAN
 	help
-	  Tell gcc to warn at build time for stack frames larger than this.
+	  Tell the compiler to warn at build time for stack frames larger than this.
 	  Setting this too low will cause a lot of warnings.
 	  Setting it to 0 disables the warning.
 
-- 
2.38.0.135.g90850a2211-goog