Re: Debugging hung tasks?

[Randy Dunlap]

On Fri, 22 Apr 2011 16:09:29 -0700 Ben Greear wrote:

> I am testing lots of NFS traffic against an over-loaded and slow file server.
> 
> I enabled the hung-task detection logic, and it's hitting after 180
> seconds.
> 
> First:  Is there any valid reason to have funky NFS cause a hung task?
> 
> Second: Why doesn't the hung-task panic logic print the stack trace of
>     the hung task?
>     Is this an option that can be enabled?

hung_task.c::check_hung_task() always calls sched_show_task() and
optionally does the panic:

	if (sysctl_hung_task_panic)
		panic("hung_task: blocked tasks");

sched.c::sched_show_task() calls show_stack(), which should be doing what
you are asking for AFAICT.  What kernel version are you using?


---
~Randy
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