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authorAndrey Konovalov <andreyknvl@google.com>2018-02-06 15:36:00 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-06 18:32:42 -0800
commit0e410e158e5baa1300bdf678cea4f4e0cf9d8b94 (patch)
treee857ad4dd093bff753dbecb2a4815a3ae84d0812 /scripts/Makefile.lib
parente237f98a9c134c3d600353f21e07db915516875b (diff)
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kasan: don't emit builtin calls when sanitization is off
With KASAN enabled the kernel has two different memset() functions, one with KASAN checks (memset) and one without (__memset). KASAN uses some macro tricks to use the proper version where required. For example memset() calls in mm/slub.c are without KASAN checks, since they operate on poisoned slab object metadata. The issue is that clang emits memset() calls even when there is no memset() in the source code. They get linked with improper memset() implementation and the kernel fails to boot due to a huge amount of KASAN reports during early boot stages. The solution is to add -fno-builtin flag for files with KASAN_SANITIZE := n marker. Link: http://lkml.kernel.org/r/8ffecfffe04088c52c42b92739c2bd8a0bcb3f5e.1516384594.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'scripts/Makefile.lib')
-rw-r--r--scripts/Makefile.lib2
1 files changed, 1 insertions, 1 deletions
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 5fdc1a19b02c..5589bae34af6 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -121,7 +121,7 @@ endif
ifeq ($(CONFIG_KASAN),y)
_c_flags += $(if $(patsubst n%,, \
$(KASAN_SANITIZE_$(basetarget).o)$(KASAN_SANITIZE)y), \
- $(CFLAGS_KASAN))
+ $(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
endif
ifeq ($(CONFIG_UBSAN),y)