Messages in this thread | | | From | Marco Elver <> | Date | Thu, 23 Sep 2021 12:07:17 +0200 | Subject | Re: [PATCH] kasan: Always respect CONFIG_KASAN_STACK |
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On Wed, 22 Sept 2021 at 22:55, Nathan Chancellor <nathan@kernel.org> wrote: > Currently, the asan-stack parameter is only passed along if > CFLAGS_KASAN_SHADOW is not empty, which requires KASAN_SHADOW_OFFSET to > be defined in Kconfig so that the value can be checked. In RISC-V's > case, KASAN_SHADOW_OFFSET is not defined in Kconfig, which means that > asan-stack does not get disabled with clang even when CONFIG_KASAN_STACK > is disabled, resulting in large stack warnings with allmodconfig: > > drivers/video/fbdev/omap2/omapfb/displays/panel-lgphilips-lb035q02.c:117:12: > error: stack frame size (14400) exceeds limit (2048) in function > 'lb035q02_connect' [-Werror,-Wframe-larger-than] > static int lb035q02_connect(struct omap_dss_device *dssdev) > ^ > 1 error generated. > > Ensure that the value of CONFIG_KASAN_STACK is always passed along to > the compiler so that these warnings do not happen when > CONFIG_KASAN_STACK is disabled. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1453 > References: 6baec880d7a5 ("kasan: turn off asan-stack for clang-8 and earlier") > Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Marco Elver <elver@google.com>
[ Which tree are you planning to take it through? ]
Note, arch/riscv/include/asm/kasan.h mentions KASAN_SHADOW_OFFSET in comment (copied from arm64). Did RISC-V just forget to copy over the Kconfig option?
> --- > scripts/Makefile.kasan | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan > index 801c415bac59..b9e94c5e7097 100644 > --- a/scripts/Makefile.kasan > +++ b/scripts/Makefile.kasan > @@ -33,10 +33,11 @@ else > CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \ > $(call cc-param,asan-globals=1) \ > $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \ > - $(call cc-param,asan-stack=$(stack_enable)) \ > $(call cc-param,asan-instrument-allocas=1) > endif > > +CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable)) > + > endif # CONFIG_KASAN_GENERIC > > ifdef CONFIG_KASAN_SW_TAGS > > base-commit: 4057525736b159bd456732d11270af2cc49ec21f > -- > 2.33.0.514.g99c99ed825 > >
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