Re: 3.5-rc6 configfs BUG_ON

From: Joel Becker
Date: Wed Aug 15 2012 - 04:30:20 EST


On Sun, Jul 15, 2012 at 07:58:31PM -0400, Dave Jones wrote:
> On Sun, Jul 15, 2012 at 01:58:46PM -0700, Joel Becker wrote:
>
> > > Call Trace:
> > > [<ffffffff811ec74f>] d_kill+0xaf/0x120
> > > [<ffffffff811ec8a2>] dput+0xe2/0x1d0
> > > [<ffffffff811dfaea>] path_put+0x1a/0x30
> > > [<ffffffff811d9705>] vfs_fstatat+0x55/0x70
> > > [<ffffffff811d973e>] vfs_lstat+0x1e/0x20
> > > [<ffffffff811d99ca>] sys_newlstat+0x1a/0x40
> > > [<ffffffff81696aed>] system_call_fastpath+0x1a/0x1f
> > > Code: f6 43 40 01 75 eb 48 8b 7b 50 e8 41 4d f6 ff 48 8b 3d c2 bf 7f 01 48 89 de e8 a2 52 f6 ff 4c 89 e7 e8 1a b5 f9 ff 5b 41 5c 5d c3 <0f> 0b be 9c 00 00 00 48 c7 c7 30 a2 9e 81 e8 42 2e e1 ff eb a7
> > > RIP [<ffffffff812562fb>] configfs_d_iput+0x8b/0xa0
> > > RSP <ffff88014325be08>
> > > ---[ end trace 65e130035db36f7d ]---
> > >
> > > 58 if (sd) {
> > > 59 BUG_ON(sd->s_dentry != dentry);
> > >
> >
> > Dave,
> > What were you doing at the time? Is this ocfs2, dlm, target, or
> > what?
> >
> > Joel
> >
>
> See http://codemonkey.org.uk/projects/trinity/
> Running that with -c newlstat should trigger it.
> (load configfs module first, no further config necessary)

Cool tool. I presume that -c newlstat just randomly picks paths to
newlstat. I think I see what's happening, but I can't see what gets the
dirent into that state. Now to get a VM I can break.

Joel

--

"The trouble with being punctual is that nobody's there to
appreciate it."
- Franklin P. Jones

http://www.jlbec.org/
jlbec@xxxxxxxxxxxx
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