Re: [syzbot] [bpf?] WARNING: locking bug in trie_delete_elem

[Aleksandr Nogikh]

On Tue, Nov 12, 2024 at 3:24 AM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> On Thu, Nov 07 2024 at 13:00, syzbot wrote:
> > syzbot has bisected this issue to:
> >
> > commit 4febce44cfebcb490b196d5d10ae9f403ca4c956
> > Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > Date:   Tue Oct 1 08:42:03 2024 +0000
> >
> >     posix-timers: Cure si_sys_private race
> >
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=129f2d87980000
> > start commit:   f9f24ca362a4 Add linux-next specific files for 20241031
> > git tree:       linux-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=169f2d87980000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=328572ed4d152be9
> > dashboard link: https://syzkaller.appspot.com/bug?extid=b506de56cbbb63148c33
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1387655f980000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11ac5540580000
> >
> > Reported-by: syzbot+b506de56cbbb63148c33@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Fixes: 4febce44cfeb ("posix-timers: Cure si_sys_private race")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> I seriously doubt that this bisection is even remotely correct.
>
> This commit has absolutely nothing to do with the lockdep splat and
> trie_delete_elem().

Yes, the bisection is wrong, please ignore it.
I've added this case to the issue that tracks the underlying problem:
https://github.com/google/syzkaller/issues/5414

-- 
Aleksandr

>
> Thanks,
>
>         tglx
>
> --