Re: 2.6.38-rc3: kernel BUG at fs/nfsd/nfs4state.c:3132!

["J. Bruce Fields" <bfields@fieldses.org>]

On Fri, Feb 11, 2011 at 12:00:36PM -0500, J. Bruce Fields wrote:
> On Fri, Feb 11, 2011 at 05:59:44PM +0100, Takashi Iwai wrote:
> > At Fri, 11 Feb 2011 17:57:21 +0100,
> > Takashi Iwai wrote:
> > > 
> > > At Fri, 11 Feb 2011 17:12:33 +0100,
> > > Takashi Iwai wrote:
> > > > 
> > > > At Fri, 11 Feb 2011 11:05:32 -0500,
> > > > J. Bruce Fields wrote:
> > > > > 
> > > > > On Fri, Feb 11, 2011 at 05:01:18PM +0100, Takashi Iwai wrote:
> > > > > > At Fri, 11 Feb 2011 10:37:02 -0500,
> > > > > > J. Bruce Fields wrote:
> > > > > > > 
> > > > > > > On Fri, Feb 11, 2011 at 04:29:56PM +0100, Takashi Iwai wrote:
> > > > > > > > At Fri, 11 Feb 2011 10:21:12 -0500,
> > > > > > > > J. Bruce Fields wrote:
> > > > > > > > > Again, 2.6.38-rc4 does not have a BUG() on line 3132.  Could you post
> > > > > > > > > the full oops message from your machine?
> > > > > > > > 
> > > > > > > > Well, on vanilla 2.6.38-rc4, it's in nfs4_preprocess_stateid_op():
> > > > > > > >                if (filpp) {
> > > > > > > >                         *filpp = find_readable_file(dp->dl_file);
> > > > > > > > ==>                     BUG_ON(!*filpp);
> > > > > > > >                 }
> > > > > > > 
> > > > > > > Oh good grief, my apologies--I mistyped "38" as "28"!
> > > > > > > 
> > > > > > > This looks like it could be a known delegation bug....  Would it be
> > > > > > > possible for you to check whether this is reproduceable on
> > > > > > > 
> > > > > > > 	git://linux-nfs.org/~bfields/topics.git for-2.6.38-incoming
> > > > > > 
> > > > > > Hm, I couldn't pull it.
> > > > > > 
> > > > > >   % git pull 'git://linux-nfs.org/~bfields/topics.git' for-2.6.38-incoming
> > > > > >   fatal: The remote end hung up unexpectedly
> > > > > 
> > > > > Should be linux-topics, apologies again:
> > > > > 
> > > > > 	git://linux-nfs.org/~bfields/linux-topics.git for-2.6.38-incoming
> > > > 
> > > > Thanks.  I'm going to give it a try now.
> > > 
> > > Looks good so far.  I'll let you know if it's triggered again.
> > 
> > Argh, too early to say.  Now I got the same one.
> > 
> > It seems that it's triggered when I start Firefox on NFS client
> > machine.
> 
> OK, thanks, I'll take a look.

I think I see the problem....  Could you try fetching that branch again?

	git://linux-nfs.org/~bfields/linux-topics.git for-2.6.38-incoming

(But I've only tested that it compiles so far.)

--b.