Re: panic: ffs_blkfree: freeing free block

2007/10/18, Arjan van Leeuwen <avleeuwen_at_gmail.com>:
>
> Hey Kostik,
>
> 2007/10/18, Kostik Belousov <kostikbel_at_gmail.com>:
> >
> > On Wed, Oct 17, 2007 at 07:05:59AM -0500, Eric Anderson wrote:
> > > Kostik Belousov wrote:
> > > >On Tue, Oct 16, 2007 at 12:20:59PM +0200, Arjan van Leeuwen wrote:
> > > >>2007/10/16, Eric Anderson < anderson_at_freebsd.org>:
> > > >>>Pieter de Goeje wrote:
> > > >>>>On Sunday 14 October 2007, Eric Anderson wrote:
> > > >>>>>Pieter de Goeje wrote:
> > > >>>>>>On Saturday 13 October 2007, Rolf Witt wrote:
> > > >>>>>>>Backtrace from crash tonight (after portsnap cron):
> > > >>>>>><snip>
> > > >>>>>>
> > > >>>>>>># uname -a
> > > >>>>>>>FreeBSD peanuts.homenet.local 7.0-PRERELEASE FreeBSD
> > 7.0-PRERELEASE
> > > >>>>>>>#121: Thu Oct 11 16:29:05 CEST 2007
> > > >>>>>>>rowi_at_peanuts.homenet.local:/usr/obj/usr/src/sys/PEANUTS  i386
> > > >>>>>>>
> > > >>>>>>>Sources from Builddate.
> > > >>>>>>>
> > > >>>>>>>Rowi
> > > >>>>>>Eric sent me this patch:
> > > >>>>>>http://www.googlebit.com/freebsd/patches/ffs_softdep.c-patch
> > > >>>>>>which seems to be working great so far. I am still testing it,
> > but I
> > > >>>>>>think it fixed the problem.
> > > >>>>>>To apply, cd /usr/src; patch < /path/to/patch and then rebuild
> > the
> > > >>>>>>kernel.
> > > >>>>>>
> > > >>>>>>Cheers,
> > > >>>>>>Pieter de Goeje
> > > >>>>>It doesn't actually 'fix' the problem, but I think it helps
> > identify
> > > >>>it.
> > > >>>>>I'm not 100% certain if this is the right fix our not, but so far
> > > >>>>>feedback has been good when running with this patch.
> > > >>>>>
> > > >>>>>Can somebody confirm that this patch is ok?
> > > >>>>>
> > > >>>>>Eric
> > > >>>>Can you elaborate on what this patch exactly does / what the
> > problem is?
> > > >>>>
> > > >>>>Pieter
> > > >>>
> > > >>>I think the problem is that blocks are being put in the worklist
> > twice,
> > > >>>but I'm not certain why yet.  The patch reduces the chance of this
> > > >>>happening by more often removing the block from the worklist
> > instead of
> > > >>>leaving it on.  I think actually the patch is hiding the real issue
> > more
> > > >>>than anything, which is why I said it isn't fixing the problem, but
> > > >>>because of the reports I've seen, I think we're sniffing in the
> > right
> > > >>>area.  I'll be looking more into this soon, when I get another few
> > > >>>minutes of free time and my debugger..
> > > >>I actually seem to be getting the panic more often with the patch (
> > i.e.
> > > >>twice in just 30 minutes with the patch, about twice per day without
> > the
> > > >>patch), while doing the same things as usual. The panic usually
> > happens
> > > >>when
> > > >>I'm compiling or linking. Is that strange?
> > > >
> > > >Patch is wrong. Actually, it does put the dirrem to the proccessing
> > twice
> > > >when xp != NULL.
> > >
> > > Yes, exactly why I said 'it doesn't fix the problem'.  In fact, I
> > > actually did not post it to the list, and didn't intend for it to be
> > > posted.  I was hoping for feedback for further examination.
> > >
> > > Kostik - do you have any ideas on what is going on here?  Did you see
> > > the message in another thread that looked similar (it was regarding
> > > gjournal)?
> >
> > No, I have no idea. BTW, some further information from the people that
> > experience the problem could be helpful. For instance,
> > UFS1/UFS2
>
> UFS2, filesystem created with FreeBSD 6-STABLE
>
> size of the problematic fs/% of the space used
>
>  /dev/ad4s1g 90613368 22619950 60744350 27% /home
>
> are quotas enabled in kernel/active for the fs ?
>
> No to both.
>
> are softupdates on ?
>
> Yes. Turning them off seems to fix the problem (fingers crossed - I only
> turned it off this morning, didn't have a panic yet)
>
After working for a whole day without softupdates, I can say that turning
them off at least causes less panics to happen than with them turned on,
maybe they even don't happen at all without softupdates; I haven't had a
panic all day, while I have one every few hours with softupdates turned on.
Arjan