On Tue, Apr 30, 2019 at 3:01 AM Nathan Chancellor <natechancellor@xxxxxxxxx> wrote: > > This is Clang's version of GCC's -Wmaybe-uninitialized. Up to this > point, it has not been used because -Wuninitialized has been disabled, > which also turns off -Wsometimes-uninitialized, meaning that we miss out > on finding some bugs [1]. In my experience, it appears to be more > accurate than GCC and catch some things that GCC can't. > > All of these warnings have now been fixed in -next across arm, arm64, > and x86_64 defconfig/allyesconfig so this should be enabled for everyone > to prevent more from easily creeping in. > > As of next-20190429: > > $ git log --oneline --grep="sometimes-uninitialized" | wc -l > 45 > > [1]: https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@xxxxxx/ > > Link: https://github.com/ClangBuiltLinux/linux/issues/381 > Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx> > --- > > Masahiro, I am not sure how you want to handle merging this with regards > to all of the patches floating around in -next but I wanted to send this > out to let everyone know this is ready to be turned on. > > Arnd, are there many remaning -Wsometimes-uninitialized warnings in > randconfigs? No, I don't see any with the patches that I submitted. I haven't checked if there are any that still need to get merged into linux-next though. > diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn > index 768306add591..f4332981ea85 100644 > --- a/scripts/Makefile.extrawarn > +++ b/scripts/Makefile.extrawarn > @@ -72,5 +72,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format) > KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare) > KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length) > KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized) > +KBUILD_CFLAGS += $(call cc-option, -Wsometimes-uninitialized) > endif > endif This doesn't look right. Shouldn't you remove the line that turns off -Wuninitilized instead of adding only -Wsometimes-uninitialized? If we warn about the instances that may or may not be wrong, we should also warn about those that are provably wrong. Arnd
