[issue715] panic at shutdown using comconsole

[Nicolas Thery]

2009/2/20 Nicolas Thery <nthery at gmail.com>:
> 2009/2/20 Thomas Nikolajsen (via DragonFly issue tracker) > (kgdb) frame 18
>> #18 0xc01fff05 in spec_close (ap=0xe8d8b9a8) at /usr/src/sys/vfs/specfs/
>> spec_vnops.c:740
>> 740                     error = dev_dclose(dev, ap->a_fflag, S_IFCHR);
>> (kgdb) print p
>> $1 = (struct proc *) 0xe8f0d218
>> (kgdb) print p->p_session
>> There is no member named p_session.
>
> Sorry I forgot that p_session is a macro.
>
>> (kgdb) print p->p_pgrp
>> $2 = (struct pgrp *) 0xe9167ec0
>> (kgdb) print p->p_pgrp->pg_session
>> $3 = (struct session *) 0xd3ba1a60
>> (kgdb) print p->p_pgrp->pg_session->s_ttyvp
>> $4 = (struct vnode *) 0x0
>
> Cool.  That's consistent with my hypothesis.  I reckon it was
> nullified when executing the body of the 2nd if statement in
> spec_close().  I'll fix it tonight.
>
> Thanks a lot.
>
> Nicolas
>

I've committed a potential fix.