Re: Soft lockup problem

From: Jan Kara
Date: Mon Feb 06 2012 - 17:51:22 EST

On Mon 06-02-12 09:40:45, Gerard Saraber wrote:
> Greetings everyone,
> I've been having a bit of a problem since upgrading to the linux 3.x
> series, I have a machine that we're using as a NAS that runs various
> rsync processes (mostly at night), lately after a day or two, I will
> come in in the morning to a load average of 49, but the machine not
> really doing anything, when trying to run 'dstat' the command just
> hung with no output at all. there were no errors in the logs, or even
> anything that would vaguely point at anything I could work with.
> So needing to get the machine back to work I attempted to reboot it
> "shutdown -r now" on console... it gives a nice message saying it's
> going to reboot, but nothing ever happens.. the only way to reboot it
> is by using ctrl + alt + sysrq + b. after which the machine reboots
> and the raid array comes back clean.
> I'm not sure how to troubleshoot this, any pointers would be appreciated.
> I'm compiling 3.2.4 at the moment and found a bunch of possibly useful
> options in the kernel debugging section:
> detect hard/soft lockups and detect hung tasks, maybe it'll give me
> something more to go on.
> Some details about the machine:
> Linux xenbox 3.2.2 #1 SMP Sun Jan 29 10:28:22 CST 2012 x86_64 Intel(R)
> Xeon(R) CPU 5140 @ 2.33GHz GenuineIntel GNU/Linux
> It has 3 software raid arrays (2 x 5 drives and 1 x 4 drives) LVM'ed
> together into a 23TB XFS filesystem.
> 6GB memory and a pair of Intel Gigabit ethernet controllers bonded together.
Hmm, might be some deadlock in the filesystem. Adding XFS guys to CC.
Can you run 'echo w >/proc/sysrq-trigger' and post output of dmesg here?

Jan Kara <jack@xxxxxxx>
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at