linux-hardened/lib/Kconfig.ubsan
Andrey Ryabinin dde5cf39d4 ubsan: fix tree-wide -Wmaybe-uninitialized false positives
-fsanitize=* options makes GCC less smart than usual and increase number
of 'maybe-uninitialized' false-positives. So this patch does two things:

 * Add -Wno-maybe-uninitialized to CFLAGS_UBSAN which will disable all
   such warnings for instrumented files.

 * Remove CONFIG_UBSAN_SANITIZE_ALL from all[yes|mod]config builds. So
   the all[yes|mod]config build goes without -fsanitize=* and still with
   -Wmaybe-uninitialized.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00

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config ARCH_HAS_UBSAN_SANITIZE_ALL
bool
config UBSAN
bool "Undefined behaviour sanity checker"
help
This option enables undefined behaviour sanity checker
Compile-time instrumentation is used to detect various undefined
behaviours in runtime. Various types of checks may be enabled
via boot parameter ubsan_handle (see: Documentation/ubsan.txt).
config UBSAN_SANITIZE_ALL
bool "Enable instrumentation for the entire kernel"
depends on UBSAN
depends on ARCH_HAS_UBSAN_SANITIZE_ALL
# We build with -Wno-maybe-uninitilzed, but we still want to
# use -Wmaybe-uninitilized in allmodconfig builds.
# So dependsy bellow used to disable this option in allmodconfig
depends on !COMPILE_TEST
default y
help
This option activates instrumentation for the entire kernel.
If you don't enable this option, you have to explicitly specify
UBSAN_SANITIZE := y for the files/directories you want to check for UB.
Enabling this option will get kernel image size increased
significantly.
config UBSAN_ALIGNMENT
bool "Enable checking of pointers alignment"
depends on UBSAN
default y if !HAVE_EFFICIENT_UNALIGNED_ACCESS
help
This option enables detection of unaligned memory accesses.
Enabling this option on architectures that support unaligned
accesses may produce a lot of false positives.