+ kasan-always-respect-config_kasan_stack.patch added to -mm tree

+ kasan-always-respect-config_kasan_stack.patch added to -mm tree

[akpm]

The patch titled
     Subject: kasan: always respect CONFIG_KASAN_STACK
has been added to the -mm tree.  Its filename is
     kasan-always-respect-config_kasan_stack.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/kasan-always-respect-config_kasan_stack.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/kasan-always-respect-config_kasan_stack.patch

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------------------------------------------------------
From: Nathan Chancellor <nathan@kernel.org>
Subject: kasan: always respect CONFIG_KASAN_STACK

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")
Link: https://lkml.kernel.org/r/20210922205525.570068-1-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 scripts/Makefile.kasan |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/scripts/Makefile.kasan~kasan-always-respect-config_kasan_stack
+++ a/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
_

Patches currently in -mm which might be from nathan@kernel.org are

kasan-always-respect-config_kasan_stack.patch