XFS assertion from truncate. (3.10-rc2)

[Dave Jones]

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
 > 
 > but I can't set how this makes any difference to the problem at all.
 > See my previous post about the fact that 0xa068 is actually a valid
 > mask and should not be tripping the assert....

Hmm, I did git bisect fs/xfs/, so maybe itit's something outside of that subdir
that's the cause. I'll start over on the whole tree once I'm done bisecting
another entirely different bug.

	Dave