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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 /scripts
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 'scripts')
-rw-r--r--scripts/Makefile.kasan5
-rw-r--r--scripts/gcc-plugins/Kconfig4
2 files changed, 0 insertions, 9 deletions
diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 6deabedc67fc..6410bd22fe38 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -27,14 +27,9 @@ else
$(call cc-param,asan-globals=1) \
$(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
$(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \
- $(call cc-param,asan-use-after-scope=1) \
$(call cc-param,asan-instrument-allocas=1)
endif
-ifdef CONFIG_KASAN_EXTRA
-CFLAGS_KASAN += $(call cc-option, -fsanitize-address-use-after-scope)
-endif
-
endif # CONFIG_KASAN_GENERIC
ifdef CONFIG_KASAN_SW_TAGS
diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index d45f7f36b859..d9fd9988ef27 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -68,10 +68,6 @@ config GCC_PLUGIN_LATENT_ENTROPY
config GCC_PLUGIN_STRUCTLEAK
bool "Force initialization of variables containing userspace addresses"
- # Currently STRUCTLEAK inserts initialization out of live scope of
- # variables from KASAN point of view. This leads to KASAN false
- # positive reports. Prohibit this combination for now.
- depends on !KASAN_EXTRA
help
This plugin zero-initializes any structures containing a
__user attribute. This can prevent some classes of information