lib/ubsan: remove null-pointer checks
authorAndrey Ryabinin <aryabinin@virtuozzo.com>
Sat, 11 Aug 2018 00:23:03 +0000 (17:23 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 11 Aug 2018 03:19:58 +0000 (20:19 -0700)
commit3ca17b1f3628f916f79e0ab62f1bf0e45ec9ba92
tree079b00ad1bc4e3dd0770f091a7a8b62d851a73b8
parent5832fcf9990c0e72c468e0dc6022836bb1b8d1e8
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>
arch/parisc/Kconfig
arch/s390/Kconfig
lib/Kconfig.ubsan
scripts/Makefile.ubsan