Re: [Bug #32982] Kernel locks up a few minutes after boot

NeilBrown
2011-04-17T21:07:11Z

On Sun, 17 Apr 2011 20:37:39 +0200 Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org> wrote:

> On Sun, Apr 17, 2011 at 7:03 PM, Linus Torvalds
> <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> wrote:
> > On Sun, Apr 17, 2011 at 5:57 AM, Rafael J. Wysocki <rjw-KKrjLPT3xs0@public.gmane.org> wrote:
> > > This message has been generated automatically as a part of a summary report
> > > of recent regressions.
> > >
> > > The following bug entry is on the current list of known regressions
> > > from 2.6.38.  Please verify if it still should be listed and let the tracking team
> > > know (either way).
> > >
> > >
> > > Bug-Entry       : http://bugzilla.kernel.org/show_bug.cgi?id=32982
> > > Subject         : Kernel locks up a few minutes after boot
> > > Submitter       : Bart Van Assche <bart.vanassche-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > > Date            : 2011-04-10 19:55 (8 days old)
> >
> > Is this machine running a RAID5 setup or something like that?
> >
> > There is a known interaction with the new block layer plugging code
> > and MD. The "hung task" report in that bugzilla looks very much like
> > that issue. And you do have "root=/dev/md0", so clearly there's some
> > md thing going on.
> >
> > And bisecting might not work all that well for it, because I suspect
> > it ends up being very much a matter of IO patterns how it triggers.
> >
> > Neil supposedly has a patch for it, but I haven't seen it yet. Neil, Jens?
>
> (converted top-posting into bottom-posting)
>
> Hello Linus,
>
> On the system on which bug #32982 has been triggered md0, md1 and md2
> have been configured as two-disk RAID1 (mirroring).

If any of those have write-intent bitmaps then I definitely know what the
problem is and I'll be posting patches later today (probably not much later).

If not .. then I'm less sure but it would certainly be worth testing after
applying the promised fixes.

NeilBrown

>
> I've done my best to trigger enough I/O in order to obtain reliable
> bisect results. A difficulty I encountered during bisecting though was
> that I encountered unbootable kernels (all skipped revisions).
>
> Bart.