1a6a1dbeb7
When booting an allmodconfig kernel, there are a lot of false-positives. With a message like this 'UBSAN: Undefined behaviour in...' with a call trace that follows. UBSAN warnings are a result of enabling noisy CONFIG_UBSAN_ALIGNMENT which is disabled by default if HAVE_EFFICIENT_UNALIGNED_ACCESS=y. It's noisy even if don't have efficient unaligned access, e.g. people often add __cacheline_aligned_in_smp in structs, but forget to align allocations of such struct (kmalloc() give 8-byte alignment in worst case). Rework so that when building a allmodconfig kernel that turns everything into '=m' or '=y' will turn off UBSAN_ALIGNMENT. [aryabinin@virtuozzo.com: changelog addition] Link: http://lkml.kernel.org/r/20181217150326.30933-1-anders.roxell@linaro.org Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Suggested-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
49 lines
1.6 KiB
Plaintext
49 lines
1.6 KiB
Plaintext
config ARCH_HAS_UBSAN_SANITIZE_ALL
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bool
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config UBSAN
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bool "Undefined behaviour sanity checker"
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help
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This option enables undefined behaviour sanity checker
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Compile-time instrumentation is used to detect various undefined
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behaviours in runtime. Various types of checks may be enabled
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via boot parameter ubsan_handle
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(see: Documentation/dev-tools/ubsan.rst).
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config UBSAN_SANITIZE_ALL
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bool "Enable instrumentation for the entire kernel"
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depends on UBSAN
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depends on ARCH_HAS_UBSAN_SANITIZE_ALL
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# We build with -Wno-maybe-uninitilzed, but we still want to
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# use -Wmaybe-uninitilized in allmodconfig builds.
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# So dependsy bellow used to disable this option in allmodconfig
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depends on !COMPILE_TEST
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default y
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help
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This option activates instrumentation for the entire kernel.
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If you don't enable this option, you have to explicitly specify
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UBSAN_SANITIZE := y for the files/directories you want to check for UB.
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Enabling this option will get kernel image size increased
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significantly.
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config UBSAN_NO_ALIGNMENT
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bool "Disable checking of pointers alignment"
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depends on UBSAN
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default y if HAVE_EFFICIENT_UNALIGNED_ACCESS
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help
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This option disables the check of unaligned memory accesses.
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This option should be used when building allmodconfig.
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Disabling this option on architectures that support unaligned
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accesses may produce a lot of false positives.
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config UBSAN_ALIGNMENT
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def_bool !UBSAN_NO_ALIGNMENT
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config TEST_UBSAN
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tristate "Module for testing for undefined behavior detection"
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depends on m && UBSAN
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help
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This is a test module for UBSAN.
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It triggers various undefined behavior, and detect it.
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