Messages in this thread | | | From | Masahiro Yamada <> | Date | Thu, 27 Oct 2022 23:31:49 +0900 | Subject | Re: [PATCH 3/5] Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default |
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On Tue, Oct 25, 2022 at 6:22 AM Alexander Potapenko <glider@google.com> wrote: > > 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
This is wrong.
Kconfig picks up the first default entry which has true 'if' condition.
Since (!64BIT || 64BIT) covers all the possible cases, this patch is just adding dead code.
> 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 >
-- Best Regards Masahiro Yamada
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