panic, seems related to r234386

[Sergey Kandaurov]

On 8 May 2012 00:11, Mateusz Guzik <mjguzik at gmail.com> wrote:
> On Mon, May 07, 2012 at 12:28:41PM -0700, Doug Barton wrote:
>> On 05/06/2012 15:19, Sergey Kandaurov wrote:
>> > On 7 May 2012 01:54, Doug Barton <dougb at freebsd.org> wrote:
>> >> I got this with today's current, previous (working) kernel is r232719.
>> >>
>> >> panic: _mtx_lock_sleep: recursed on non-recursive mutex struct mount mtx
>> >> @ /frontier/svn/head/sys/kern/vfs_subr.c:4595
>>
>> ...
>>
>> > Please try this patch.
>> >
>> > Index: fs/ext2fs/ext2_vfsops.c
>> > ===================================================================
>> > --- fs/ext2fs/ext2_vfsops.c     (revision 235108)
>> > +++ fs/ext2fs/ext2_vfsops.c     (working copy)
>> > @@ -830,7 +830,6 @@
>> >         /*
>> >          * Write back each (modified) inode.
>> >          */
>> > -       MNT_ILOCK(mp);
>> >  loop:
>> >         MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
>> >                 if (vp->v_type == VNON) {
>> >
>>
>> Didn't help, sorry. I put 234385 through some pretty heavy load
>> yesterday, and everything was fine. As soon as I move up to 234386, the
>> panic triggered again. So I cleaned everything up, applied your patch,
>> built a kernel from scratch, and rebooted. It was Ok for a few seconds
>> after boot, then panic'ed again, I think in a different place, but I'm
>> not sure because subsequent attempts to fsck the file systems caused new
>> panics which overwrote the old ones before they could be saved.
>>
>
> Another MNT_ILOCK was hiding few lines below, try this patch:
>
> http://student.agh.edu.pl/~mjguzik/patches/ext2fs-ilock.patch
>
> I've tested this a bit and I believe this fixes your problem.

I just committed your fix in r235241 since it seems to have no
relation to the problem reported by Peter Holm.

-- 
wbr,
pluknet