On Tue, 20 Oct 2009, Dave Chinner wrote:

On Mon, Oct 19, 2009 at 06:18:58AM -0400, Justin Piszcz wrote:

quoted

On Mon, 19 Oct 2009, Dave Chinner wrote:

quoted

On Sun, Oct 18, 2009 at 04:17:42PM -0400, Justin Piszcz wrote:

quoted

It has happened again, all sysrq-X output was saved this time.

.....

All pointing to log IO not completing.

....

quoted

So far I do not have a reproducible test case,

Ok. What sort of load is being placed on the machine?

Hello, generally the load is low, it mainly serves out some samba shares.

quoted

the only other thing not posted was the output of ps auxww during
the time of the lockup, not sure if it will help, but here it is:

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0  10320   684 ?        Ss   Oct16   0:00 init [2]

....

quoted

root       371  0.0  0.0      0     0 ?        R<   Oct16   0:01 [xfslogd/0]
root       372  0.0  0.0      0     0 ?        S<   Oct16   0:00 [xfslogd/1]
root       373  0.0  0.0      0     0 ?        S<   Oct16   0:00 [xfslogd/2]
root       374  0.0  0.0      0     0 ?        S<   Oct16   0:00 [xfslogd/3]
root       375  0.0  0.0      0     0 ?        R<   Oct16   0:00 [xfsdatad/0]
root       376  0.0  0.0      0     0 ?        S<   Oct16   0:00 [xfsdatad/1]
root       377  0.0  0.0      0     0 ?        S<   Oct16   0:03 [xfsdatad/2]
root       378  0.0  0.0      0     0 ?        S<   Oct16   0:01 [xfsdatad/3]
root       379  0.0  0.0      0     0 ?        S<   Oct16   0:00 [xfsconvertd/0]
root       380  0.0  0.0      0     0 ?        S<   Oct16   0:00 [xfsconvertd/1]
root       381  0.0  0.0      0     0 ?        S<   Oct16   0:00 [xfsconvertd/2]
root       382  0.0  0.0      0     0 ?        S<   Oct16   0:00 [xfsconvertd/3]

.....

It appears that both the xfslogd and the xfsdatad on CPU 0 are in
the running state but don't appear to be consuming any significant
CPU time. If they remain like this then I think that means they are
stuck waiting on the run queue.  Do these XFS threads always appear
like this when the hang occurs? If so, is there something else that
is hogging CPU 0 preventing these threads from getting the CPU?

Yes, the XFS threads show up like this on each time the kernel crashed.  So far
with 2.6.30.9 after ~48hrs+ it has not crashed.  So it appears to be some issue
between 2.6.30.9 and 2.6.31.x when this began happening.  Any recommendations
on how to catch this bug w/certain options enabled/etc?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com