Messages in this thread | | | Date | Wed, 08 Jun 2022 17:39:36 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] s390: disable -Warray-bounds |
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On June 8, 2022 4:59:29 PM PDT, Linus Torvalds <torvalds@linux-foundation.org> wrote: >On Wed, Jun 8, 2022 at 2:33 PM Kees Cook <keescook@chromium.org> wrote: >> >> I and others have been working through a bunch of them, though yes, >> they're not all fixed yet. I've been trying to track it here[1], but >> many of those fixes are only in -next. > >Hmm. Even with that disabled, I get a few warnings I *really* would >want to get rid of.
Yup! :)
> >The one in ipuv3-crtc.c seems valid about "address used as boolean is >always true". > >The 'dangling-pointer' warning does seem interesting, but not when the >compiler does as bad a job as gcc seems to do. > >See the attached patch for > > (a) make the s390 "use -Wno-array-bounds for gcc-12" be generic > > (b) fix the ipuv3-crtc.c one. IMX people? > > (c) disable -Wdangling-pointer entirely for now
I'll take a look; thanks! Should I send them back as a pull request?
>but that still leaves the netfs_i_context games, which gcc-12 is very >unhappy about:
Yeah. Happily, this has already been solved, but it looks like David didn't do a pull yet for it?
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=fscache-next
>I'd like to use something more surgical than >CONFIG_CC_NO_ARRAY_BOUNDS, but considering the s390 issues, it may not >even be worth it. Kees, just how far away are we from that being ok on >x86-64?
For gcc's UBSAN_SHIFT (I typoed this in my first reply) bug, netdev has been moving it to W=1 builds on a per-source basis for the moment:
https://git.kernel.org/linus/e95032988053c17baf6c7e27024f5103a19a5f4a
Some discussion: https://lore.kernel.org/lkml/202205231229.CF6B8471@keescook/
Perhaps these could be even more carefully limited to GCC 12 only, using the Kconfig you suggested?
-Kees
-- Kees Cook
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