Re: [syzbot] WARNING in mntput_no_expire (3)

From: Al Viro
Date: Tue May 17 2022 - 21:58:50 EST


On Wed, May 18, 2022 at 01:10:20AM +0000, Al Viro wrote:
> On Wed, May 18, 2022 at 12:59:46AM +0000, Al Viro wrote:
> > On Tue, May 17, 2022 at 10:58:15PM +0000, Al Viro wrote:
> > > On Tue, May 17, 2022 at 03:49:07PM -0700, syzbot wrote:
> > > > Hello,
> > > >
> > > > syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> > > > WARNING in mntput_no_expire
> > >
> > > Obvious question: which filesystem it is?
> >
> > FWIW, can't reproduce here - at least not with C reproducer +
> > -rc7^ kernel + .config from report + debian kvm image (bullseye,
> > with systemd shite replaced with sysvinit, which might be relevant).
> >
> > In case systemd-specific braindamage is needed to reproduce it...
> > Hell knows; at least mount --make-rshared / doesn't seem to suffice.
>
> ... doesn't reproduce with genuine systemd either. FWIW, 4-way SMP
> setup here.

OK, reproduced...