Re: Processes stuck on D state on Dual Opteron

Andrew Morton
2005-04-10T02:48:05Z

Claudio Martins <ctpm@rnl.ist.utl.pt> wrote:
>
> I repeated the test to try to get more output from alt-sysreq-T, but it
> oopsed again with even less output.
> By the way, I have also tested 2.6.11.6 and I get stuck processes in the
> same way. With 2.6.9 I get a hard lockup with no working alt-sysrq, after
> about 30 to 60mins of stress.

It could be an md deadlock, or it could be an out-of-memory deadlock. md
trying to allocate memory on the swapout path.

> This is with preempt enabled (as well as BKL preempt). I want to test also
> without preempt and also without using MD Raid1, but I'll have to reach the
> machine and hit the power button, so not possible until tomorrow :-(
>
> The original original message in this thread containing the details of the
> setup and a .config is at:
>
> http://marc.theaimsgroup.com/?l=linux-kernel&m=111266784320156&w=2
>
> I am happy to test any patches and also wonder if enabling any of the
> options in the kernel debugging section could help in trying to find where
> the deadlock is.

Suggest you boot with `nmi_watchdog=0' to prevent the nmi watchdog from
cutting in during long sysrq traces.

Also, capture the `sysrq-m' output so we can see if the thing is out of
memory.