On Thu, Dec 5, 2019 at 11:22 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 05/12/19 11:16, Dmitry Vyukov wrote: > > On Thu, Dec 5, 2019 at 11:13 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > >> > >> On 04/12/19 22:41, syzbot wrote: > >>> syzbot has bisected this bug to: > >>> > >>> commit 2de50e9674fc4ca3c6174b04477f69eb26b4ee31 > >>> Author: Russell Currey <ruscur@xxxxxxxxxx> > >>> Date: Mon Feb 8 04:08:20 2016 +0000 > >>> > >>> powerpc/powernv: Remove support for p5ioc2 > >>> > >>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=127a042ae00000 > >>> start commit: 76bb8b05 Merge tag 'kbuild-v5.5' of > >>> git://git.kernel.org/p.. > >>> git tree: upstream > >>> final crash: https://syzkaller.appspot.com/x/report.txt?x=117a042ae00000 > >>> console output: https://syzkaller.appspot.com/x/log.txt?x=167a042ae00000 > >>> kernel config: https://syzkaller.appspot.com/x/.config?x=dd226651cb0f364b > >>> dashboard link: > >>> https://syzkaller.appspot.com/bug?extid=4455ca3b3291de891abc > >>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11181edae00000 > >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=105cbb7ae00000 > >>> > >>> Reported-by: syzbot+4455ca3b3291de891abc@xxxxxxxxxxxxxxxxxxxxxxxxx > >>> Fixes: 2de50e9674fc ("powerpc/powernv: Remove support for p5ioc2") > >>> > >>> For information about bisection process see: > >>> https://goo.gl/tpsmEJ#bisection > >>> > >> > >> Why is everybody being CC'd, even if the bug has nothing to do with the > >> person's subsystem? > > > > The To list should be intersection of 2 groups of emails: result of > > get_maintainers.pl on the file identified as culprit in the crash > > message + emails extracted from the bisected to commit. > > Ah, and because the machine is a KVM guest, kvm_wait appears in a lot of > backtrace and I get to share syzkaller's joy every time. :) I don't see any mention of "kvm" in the crash report. And it's only 1 file, not all of them, in this case I would expect it to be drivers/video/fbdev/core/fbcon.c. So it should be something different. > This bisect result is bogus, though Tetsuo found the bug anyway. > Perhaps you can exclude commits that only touch architectures other than > x86? We do this. It work sometimes. But sometimes it hits non-deterministic kernel build bugs: https://github.com/google/syzkaller/issues/1271#issuecomment-559093018 And in this case it hit some git bisect weirdness which I can't explain yet: https://github.com/google/syzkaller/issues/1527
