Re: XFS assertion from truncate. (3.10-rc2)

[Dave Jones]

On Thu, May 23, 2013 at 11:17:21AM -0400, Dave Jones wrote:
 > On Thu, May 23, 2013 at 08:09:33AM +1000, Dave Chinner wrote:
 >  > On Wed, May 22, 2013 at 12:19:46PM -0400, Dave Jones wrote:
 >  > > On Wed, May 22, 2013 at 10:22:52AM -0400, Dave Jones wrote:
 >  > >  > On Wed, May 22, 2013 at 03:51:47PM +1000, Dave Chinner wrote:
 >  > >  > 
 >  > >  >  > > Tomorrow I'll also try running some older kernels with the same
 >  > >  >  > > options to see if it's something new, or an older bug. This is a
 >  > >  >  > > new machine, so it may be something that's been around for a
 >  > >  >  > > while, and for whatever reason, my other machines don't hit
 >  > >  >  > > this.
 >  > >  >  > 
 >  > >  >  > Another thing that just occurred to me - what compiler are you
 >  > >  >  > using?  We had a report last week on #xfs that xfsdump was failing
 >  > >  >  > with bad checksums because of link time optimisation (LTO) in
 >  > >  >  > gcc-4.8.0. When they turned that off, everything worked fine. So if
 >  > >  >  > you are using 4.8.0, perhaps trying a different compiler might be a
 >  > >  >  > good idea, too.
 >  > >  > 
 >  > >  > Yeah, this is 4.8.0. This box is running F19-beta. 
 >  > >  > I managed to shoehorn the gcc-4.7 from f18 on there though.
 >  > >  > Bug reproduced instantly, so I think we can rule out compiler.
 >  > >  > 
 >  > >  > I ran 3.9 with the same debug options. Seems stable.
 >  > >  > I'll do a bisect.
 >  > > 
 >  > > good news.  It wasn't until I started bisecting I realised I was still
 >  > > carrying this patch from you to fix slab corruption I was seeing.
 >  > > 
 >  > > It seems to be the culprit (or is masking another problem -- I had to apply
 >  > > it at each step of the bisect to get past the slab corruption bug).
 >  > 
 >  > That doesn't make a whole lot of sense to me. The fix in the xfsdev
 >  > tree is a little different:
 >  > 
 >  > http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/xfs.git;a=commitdiff;h=52c24ad39ff02d7bd73c92eb0c926fb44984a41d
 > 
 > I did an rc2 build with just that commit on top, and can't reproduce this at all now.
 > (At least not with the reproducer that worked previously).

Ok, scratch all that. I can reproduce it again, it just takes longer.
(And typically, I didn't have your debug patch on top for that run.. nnnngh)

	Dave


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