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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2019-03-05 15:41:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 21:07:13 -0800
commit7771bdbbfd3d6f204631b6fd9e1bbc30cd15918e (patch)
tree1f715a5317669f6473d1d4ddb4f5bf761e918e71 /arch/arm64/include/asm/memory.h
parentmm: hwpoison: fix thp split handing in soft_offline_in_use_page() (diff)
downloadlinux-dev-7771bdbbfd3d6f204631b6fd9e1bbc30cd15918e.tar.xz
linux-dev-7771bdbbfd3d6f204631b6fd9e1bbc30cd15918e.zip
kasan: remove use after scope bugs detection.
Use after scope bugs detector seems to be almost entirely useless for the linux kernel. It exists over two years, but I've seen only one valid bug so far [1]. And the bug was fixed before it has been reported. There were some other use-after-scope reports, but they were false-positives due to different reasons like incompatibility with structleak plugin. This feature significantly increases stack usage, especially with GCC < 9 version, and causes a 32K stack overflow. It probably adds performance penalty too. Given all that, let's remove use-after-scope detector entirely. While preparing this patch I've noticed that we mistakenly enable use-after-scope detection for clang compiler regardless of CONFIG_KASAN_EXTRA setting. This is also fixed now. [1] http://lkml.kernel.org/r/<20171129052106.rhgbjhhis53hkgfn@wfg-t540p.sh.intel.com> Link: http://lkml.kernel.org/r/20190111185842.13978-1-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Will Deacon <will.deacon@arm.com> [arm64] Cc: Qian Cai <cai@lca.pw> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--arch/arm64/include/asm/memory.h4
1 files changed, 0 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 0c656850eeea..b01ef0180a03 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -80,11 +80,7 @@
*/
#ifdef CONFIG_KASAN
#define KASAN_SHADOW_SIZE (UL(1) << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT))
-#ifdef CONFIG_KASAN_EXTRA
-#define KASAN_THREAD_SHIFT 2
-#else
#define KASAN_THREAD_SHIFT 1
-#endif /* CONFIG_KASAN_EXTRA */
#else
#define KASAN_SHADOW_SIZE (0)
#define KASAN_THREAD_SHIFT 0