[BUG] linux 2.6.0-test8 reaim tests fail to exit

[BUG] linux 2.6.0-test8 reaim tests fail to exit

[Dave Olien]

I've observed in the last two days, linux 2.6.0-test8 and I think
linux 2.6.0-test8-mm1.  The reaim test workload fails to exit.
All of the reaim tasks are blocked in sys_wait4().  But non of
them seem to have any obvious child processes.

There are also lots of sync() processes.  Many of those seem to be
blocked somewhere scheduling IO.  These kernels were all with the
as-isoched IO scheduler.  I may retry with deadline scheduler, just
to rule out IO scheduler. Is there any link between the sync()
processes and the reaim waiting for children?

Could there be a problem with IO not completing for the sync()
tasks that causes the reaim tasks to not complete?

Attached is a console output from a system hung in this state.
Included (towards the bottom) is a sysrq t output.

I'm hoping to investigate this more closely over the week end.

Re: [BUG] linux 2.6.0-test8 reaim tests (attachment URL)

[Dave Olien]

My attachment was too big to send directly to lkml.
You can find it at:

	http://developer.osdl.org/dmo/REAIM/typescript_stp8-002

On Fri, Oct 24, 2003 at 03:08:21PM -0700, Dave Olien wrote:
> 
> I've observed in the last two days, linux 2.6.0-test8 and I think
> linux 2.6.0-test8-mm1.  The reaim test workload fails to exit.
> All of the reaim tasks are blocked in sys_wait4().  But non of
> them seem to have any obvious child processes.
> 
> There are also lots of sync() processes.  Many of those seem to be
> blocked somewhere scheduling IO.  These kernels were all with the
> as-isoched IO scheduler.  I may retry with deadline scheduler, just
> to rule out IO scheduler. Is there any link between the sync()
> processes and the reaim waiting for children?
> 
> Could there be a problem with IO not completing for the sync()
> tasks that causes the reaim tasks to not complete?
> 
> Attached is a console output from a system hung in this state.
> Included (towards the bottom) is a sysrq t output.
> 
> I'm hoping to investigate this more closely over the week end.

Re: [BUG] linux 2.6.0-test8 reaim tests fail to exit

[Nick Piggin]

Dave Olien wrote:

>I've observed in the last two days, linux 2.6.0-test8 and I think
>linux 2.6.0-test8-mm1.  The reaim test workload fails to exit.
>All of the reaim tasks are blocked in sys_wait4().  But non of
>them seem to have any obvious child processes.
>
>There are also lots of sync() processes.  Many of those seem to be
>blocked somewhere scheduling IO.  These kernels were all with the
>as-isoched IO scheduler.  I may retry with deadline scheduler, just
>to rule out IO scheduler. Is there any link between the sync()
>processes and the reaim waiting for children?
>
>Could there be a problem with IO not completing for the sync()
>tasks that causes the reaim tasks to not complete?
>
>Attached is a console output from a system hung in this state.
>Included (towards the bottom) is a sysrq t output.
>
>I'm hoping to investigate this more closely over the week end.
>

Looks like IO scheduler. Testing deadline would be good. Thanks.