Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)

[Uladzislau Rezki]

On Thu, Jun 12, 2025 at 09:42:32AM +0200, Aleksandr Nogikh wrote:
> On Wed, Jun 11, 2025 at 10:58 PM Boqun Feng <boqun.feng@xxxxxxxxx> wrote:
> >
> > On Wed, Jun 11, 2025 at 12:57:04PM -0700, syzbot wrote:
> > > Hello,
> > >
> > > syzbot has tested the proposed patch and the reproducer did not trigger any issue:
> > >
> > > Reported-by: syzbot+80e5d6f453f14a53383a@xxxxxxxxxxxxxxxxxxxxxxxxx
> > > Tested-by: syzbot+80e5d6f453f14a53383a@xxxxxxxxxxxxxxxxxxxxxxxxx
> > >
> > > Tested on:
> > >
> > > commit:         488ef356 KEYS: Invert FINAL_PUT bit
> > > git tree:       upstream
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=129a660c580000
> >
> > Is there a way to see the whole console output? If Ulad's patch fixes
> > the exact issue, we should be able to see a WARN_ON_ONCE() triggered.
> 
> If WARN_ON_ONCE() were triggered, the associated kernel panic output
> would have been at the end of this log.
> 
> >
> > Regards,
> > Boqun
> >
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=713d218acd33d94
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
> 
> FWIW the last time the bug was observed on syzbot was 100 days ago, so
> it has likely been fixed since then or has become much harder to
> reproduce.
> 
That is even worse, if it is last for 100 days already.

--
Uladzislau Rezki