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Andrey Ryabinin
7771bdbbfd
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/<[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Andrey Ryabinin <[email protected]> Acked-by: Will Deacon <[email protected]> [arm64] Cc: Qian Cai <[email protected]> Cc: Alexander Potapenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: Catalin Marinas <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
52 lines
1.4 KiB
Makefile
52 lines
1.4 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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ifdef CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_INLINE
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call_threshold := 10000
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else
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call_threshold := 0
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endif
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KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
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CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
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cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
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# -fasan-shadow-offset fails without -fsanitize
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CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
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-fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
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$(call cc-option, -fsanitize=kernel-address \
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-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
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ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
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CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
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else
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# Now add all the compiler specific options that are valid standalone
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CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
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$(call cc-param,asan-globals=1) \
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$(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
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$(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \
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$(call cc-param,asan-instrument-allocas=1)
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endif
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endif # CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_SW_TAGS
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ifdef CONFIG_KASAN_INLINE
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instrumentation_flags := -mllvm -hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
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else
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instrumentation_flags := -mllvm -hwasan-instrument-with-calls=1
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endif
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CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
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-mllvm -hwasan-instrument-stack=0 \
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$(instrumentation_flags)
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endif # CONFIG_KASAN_SW_TAGS
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ifdef CONFIG_KASAN
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CFLAGS_KASAN_NOSANITIZE := -fno-builtin
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endif
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