frequent kernel BUG and lockups - 2.6.39 + xfs_fsr

[Dave Chinner]

On Tue, Aug 09, 2011 at 06:35:25PM +0200, Marc Lehmann wrote:
> > > [248359.646330] CPU 1
> > > [248359.646326] last sysfs file: /sys/devices/virtual/net/lo/operstate
> > > [248359.646323] Oops: 0000 [#1] SMP
> > > [248359.646319] PGD 8b43067 PUD 1bc63067 PMD 0
> > > [248359.646292] IP: [<ffffffffa13371ab>] xfs_trans_log_inode+0xb/0x2f [xfs]
> > > [248359.646285] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
> > 
> > And the event trace to go along with the xfs-fsr run?
> 
> It wasn't enabled yet, I didn't expect it to lock up so soon, but even if,
> we would have to wait for those rare occurances where the kernel oopses
> without the box locking up (can take months).
> 
> > I don't need to know the dmesg output - I need the information in
> > the event trace from the xfs-fsr run when the problem occurs....
> 
> And I need an XFS that doesn't oops and takes the box with it to deliver
> that :)
> 
> In any case, I am confident it will happen sooner or later.
> 
> I will then not send any kernel oopses, although I had hoped that 0-ptr
> dereferences in a specific part of a function could have been a good hint.

They tell me where the crash occurred - they don't tell me the root
cause of the problem. Understanding the root cause and fixing that
is more important that putting a bandaid over the resultant panic
(which I'll probably do anyway at the same time).

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com