Re: process 'stuck' at exit.

From: Dave Jones
Date: Tue Dec 10 2013 - 16:42:35 EST


On Tue, Dec 10, 2013 at 10:34:31PM +0100, Oleg Nesterov wrote:
> On 12/10, Dave Jones wrote:
> >
> > On Tue, Dec 10, 2013 at 09:35:59PM +0100, Oleg Nesterov wrote:
> > >
> > > I am looking at the first message and I can't understand who stuck
> > > "at exit".
> > >
> > > The trace shows that the task with pid=10818 called sys_futex() ?
> > >
> > > Perhaps "exit" means the userspace paths?
> >
> > pid 1131 is wait()'ing for 10818 to exit
> >
> > pid 1130 is periodically sending SIGKILL to 10818 because it's gotten
> > tired of waiting. 10818 is ignoring these because it's stuck in a loop
> > somewhere in the kernel.
>
> OK, thanks. So it doesn't return to user-space.
>
> could you do
>
> cd /sys/kernel/debug/tracing/
> echo 10818 >> set_ftrace_pid
> echo function_graph >> current_tracer
> echo 1 >> tracing_on
>
> and look into "trace" file to find out how exactly it loops?

http://codemonkey.org.uk/junk/trace

Dave

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