Re: panic: kernel diagnostic assertion VOP_ISLOCKET(vp) == LK_EXCLUSIVE

[Thomas Klausner <wiz%NetBSD.org@localhost>]

On Sat, Apr 16, 2022 at 05:38:22PM +0200, J. Hannken-Illjes wrote:
> > On 16. Apr 2022, at 17:27, Tobias Nygren <tnn%NetBSD.org@localhost> wrote:
> > 
> > On Sat, 16 Apr 2022 16:51:31 +0200
> > Thomas Klausner <wiz%NetBSD.org@localhost> wrote:
> > 
> >> panic: kernel diagnostic assertion "VOP_ISLOCKED(vp) == LK_EXCLUSIVE" failed: file "/usr/src/sys/miscfs/specfs/spec_vnops.c", line 1555
> >> cpu1: Begin traceback...
> >> vpanic()
> >> kern_assert()
> >> spec_close() at netbsd:spec_close+0x2fc
> >> VOP_CLOE() at netbsd:vop_close+0x42
> >> sequenceropen() at netbsd:sequenceropen+0x359
> > 
> > "cat /dev/sequencer" as a regular user is enough to trigger this. In
> > the midiseq_open() error path it is trying to VOP_CLOSE without the
> > vnode lock held. Maybe this patch helps. (Someone with filesystem
> > clue please sanity check this.)
> > 
> > --- sys/dev/sequencer.c	31 Mar 2022 19:30:15 -0000	1.76
> > +++ sys/dev/sequencer.c	16 Apr 2022 15:23:54 -0000
> > @@ -1452,8 +1452,9 @@ midiseq_open(int unit, int flags)
> > 	if ((mi.props & MIDI_PROP_CAN_INPUT) == 0)
> > 	        flags &= ~FREAD;
> > 	if ((flags & (FREAD|FWRITE)) == 0) {
> > +		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
> > 		VOP_CLOSE(vp, oflags, kauth_cred_get());
> > -		vrele(vp);
> > +		vput(vp);
> > 	        return NULL;
> > 	}
> 
> Already committed by Taylor R Campbell as sequencer.c Rev. 1.79
> on 2022/04/16 11:13:10.

Thanks - I can confirm that a kernel from yesterday doesn't have the
issue any longer.
 Thomas