Re: panic: System call lstat returning with 1 locks held

On Fri, Jan 25, 2008 at 09:00:07AM +0100, Attilio Rao wrote:
> 2008/1/25, Yar Tikhiy <yar_at_comp.chem.msu.su>:
> >
> > I don't deserve these kind words because I disinformed you seriously.
> >
> > My panic appears to be related not to UFS, but to NTFS.  Namely I
> > have an NTFS volume mounted read-only at /ntfs.  I have no idea why
> > the ports framework touches the /ntfs sub-tree, but not mounting
> > it in the first place makes the panic go away.  (I still wonder why
> > my system would also panic during buildworld, which should not touch
> > my /ntfs at all...  Now I'll try to do a buildworld w/o /ntfs mounted.)
> 
> Well, this is still to be fixed :)

No doubt. :-) But the urgency of this problem appears much lower
than that I estimated in the first place--fortunately.  Broken UFS
would be a nightmare.

> > At the same time, dismounting the NTFS volume leads to an instant
> > panic of a similar kind:
> >
> >         panic: System call unmount returning with 5 locks held
> >
> > More debug output is attached.
[...]
> Do you see any call to lockmgr_disown() in this ktr trace?
> Can you past relevant lines of it, otherwise?

I've uploaded the full "show ktr" outputs for the lstat- and
umount-triggered panics there: http://people.freebsd.org/~yar/debug/

Here's their summary:

$ awk '{print $3}' ktr_lstat.txt | sort | uniq -c
32752 _lockmgr:
   8 sharelock:
   8 shareunlock:

$ awk '{print $4}' ktr_lstat.txt | sort | uniq -c
  16 0xc322ccc0
32752 0xc37e1220

$ awk '{print $3}' ktr_umount.txt | sort | uniq -c
28663 _lockmgr:
1901 lockmgr_disown:
1102 sharelock:
1102 shareunlock:

$ awk '{print $4}' ktr_umount.txt | sort | uniq -c
4550 0xc322ccc0
 288 0xc3281220
  14 0xc3282220
 322 0xc3282660
 104 0xc33e6220
   2 0xc33e6440
   4 0xc3520220
  10 0xc3520440
  24 0xc3772220
  82 0xc3772aa0
7149 0xc3772cc0
 358 0xc3774000
17766 0xc3774220
 288 0xc3774440
1058 0xc3774660
 719 0xc3774880
  30 0xc3775000

That is, I lied again, sorry: There were calls to functions other
than _lockmgr.  But the ktr log for umount looks much more interesting
than that for lstat.

I'm ready to do more debug runs if needed--instructions are welcome.

Thank you!

-- 
Yar