[PATCH] kasan: double -Wframe-larger-than threshold if KASAN

From: Marco Elver
Date: Thu Sep 09 2021 - 06:49:43 EST


All architectures at least double stack size when using one of the KASAN
software modes that rely on compiler instrumentation.

Until now, warnings emitted by -Wframe-larger-than could easily be
ignored, as we would still get a working kernel.

However, with the introduction of -Werror (CONFIG_WERROR=y), it makes
sense to at least double the -Wframe-larger-than threshold for
software-based KASAN modes to reflect the already increased stack sizes
when building a kernel with KASAN enabled.

Link: https://lkml.kernel.org/r/YTbOs13waorzamZ6@Ryzen-9-3900X.localdomain
Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
---
lib/Kconfig.debug | 2 ++
1 file changed, 2 insertions(+)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ed4a31e34098..2055bbb6724a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -345,6 +345,8 @@ endif # DEBUG_INFO
config FRAME_WARN
int "Warn for stack frames larger than"
range 0 8192
+ default 4096 if 64BIT && (KASAN_GENERIC || KASAN_SW_TAGS)
+ default 2048 if !64BIT && (KASAN_GENERIC || KASAN_SW_TAGS)
default 2048 if GCC_PLUGIN_LATENT_ENTROPY
default 1536 if (!64BIT && PARISC)
default 1024 if (!64BIT && !PARISC)
--
2.33.0.153.gba50c8fa24-goog