Re: [syzbot] upstream build error (17)

[Nick Desaulniers]

On Wed, Apr 6, 2022 at 10:33 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> On 4/6/22 18:20, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    3e732ebf7316 Merge tag 'for_linus' of git://git.kernel.org..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=10ca0687700000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=eba855fbe3373b4f
> > dashboard link: https://syzkaller.appspot.com/bug?extid=6b36bab98e240873fd5a
> > compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+6b36bab98e240873fd5a@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > arch/x86/kvm/emulate.c:3332:5: error: stack frame size (2552) exceeds limit (2048) in function 'emulator_task_switch' [-Werror,-Wframe-larger-than]
> > drivers/block/loop.c:1524:12: error: stack frame size (2648) exceeds limit (2048) in function 'lo_ioctl' [-Werror,-Wframe-larger-than]
>
> I spot-checked these two and the stack frame is just 144 and 320 bytes
> respectively on a normal compile.  This is probably just the effect of
> some of the sanitizer options.

Yep.
$ wget -q https://syzkaller.appspot.com/x/.config\?x\=eba855fbe3373b4f
-O - | grep CONFIG_KASAN=y
CONFIG_KASAN=y
https://github.com/ClangBuiltLinux/linux/issues/39 (our oldest still-open issue)
-- 
Thanks,
~Nick Desaulniers