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| author | Andrey Ryabinin <aryabinin@virtuozzo.com> | 2018-08-10 17:23:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-10 20:19:58 -0700 |
| commit | 3ca17b1f3628f916f79e0ab62f1bf0e45ec9ba92 (patch) | |
| tree | 079b00ad1bc4e3dd0770f091a7a8b62d851a73b8 | |
| parent | 5832fcf9990c0e72c468e0dc6022836bb1b8d1e8 (diff) | |
| download | linux-4.18.y-3ca17b1f3628f916f79e0ab62f1bf0e45ec9ba92.tar.gz | |
lib/ubsan: remove null-pointer checks
With gcc-8 fsanitize=null become very noisy. GCC started to complain
about things like &a->b, where 'a' is NULL pointer. There is no NULL
dereference, we just calculate address to struct member. It's
technically undefined behavior so UBSAN is correct to report it. But as
long as there is no real NULL-dereference, I think, we should be fine.
-fno-delete-null-pointer-checks compiler flag should protect us from any
consequences. So let's just no use -fsanitize=null as it's not useful
for us. If there is a real NULL-deref we will see crash. Even if
userspace mapped something at NULL (root can do this), with things like
SMAP should catch the issue.
Link: http://lkml.kernel.org/r/20180802153209.813-1-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/parisc/Kconfig | 1 | ||||
| -rw-r--r-- | arch/s390/Kconfig | 1 | ||||
| -rw-r--r-- | lib/Kconfig.ubsan | 11 | ||||
| -rw-r--r-- | scripts/Makefile.ubsan | 4 |
4 files changed, 0 insertions, 17 deletions
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 46f656b8fc233a..e7705dde953fc7 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -11,7 +11,6 @@ config PARISC select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_STRICT_KERNEL_RWX select ARCH_HAS_UBSAN_SANITIZE_ALL - select ARCH_WANTS_UBSAN_NO_NULL select ARCH_SUPPORTS_MEMORY_FAILURE select RTC_CLASS select RTC_DRV_GENERIC diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 8a1863d9ed5338..4fe5b2affa2330 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -106,7 +106,6 @@ config S390 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF select ARCH_WANTS_DYNAMIC_TASK_STRUCT - select ARCH_WANTS_UBSAN_NO_NULL select ARCH_WANT_IPC_PARSE_VERSION select BUILDTIME_EXTABLE_SORT select CLONE_BACKWARDS2 diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index 19d42ea75ec225..98fa559ebd8086 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -1,9 +1,6 @@ config ARCH_HAS_UBSAN_SANITIZE_ALL bool -config ARCH_WANTS_UBSAN_NO_NULL - def_bool n - config UBSAN bool "Undefined behaviour sanity checker" help @@ -39,14 +36,6 @@ config UBSAN_ALIGNMENT Enabling this option on architectures that support unaligned accesses may produce a lot of false positives. -config UBSAN_NULL - bool "Enable checking of null pointers" - depends on UBSAN - default y if !ARCH_WANTS_UBSAN_NO_NULL - help - This option enables detection of memory accesses via a - null pointer. - config TEST_UBSAN tristate "Module for testing for undefined behavior detection" depends on m && UBSAN diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan index b593b36ccff869..38b2b4818e8ebf 100644 --- a/scripts/Makefile.ubsan +++ b/scripts/Makefile.ubsan @@ -14,10 +14,6 @@ ifdef CONFIG_UBSAN_ALIGNMENT CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment) endif -ifdef CONFIG_UBSAN_NULL - CFLAGS_UBSAN += $(call cc-option, -fsanitize=null) -endif - # -fsanitize=* options makes GCC less smart than usual and # increase number of 'maybe-uninitialized false-positives CFLAGS_UBSAN += $(call cc-option, -Wno-maybe-uninitialized) |