Re: perf counter issue - WARN_ON_ONCE(!list_empty(&tsk->perf_counter_ctx.counter_list));

[Peter Zijlstra <peterz@infradead.org>]

On Fri, 2009-05-15 at 18:13 +0200, Peter Zijlstra wrote:
> On Fri, 2009-05-15 at 21:28 +0530, Srivatsa Vaddagiri wrote:
> > On Fri, May 15, 2009 at 11:51:44AM -0300, Arnaldo Carvalho de Melo wrote:
> > > > hm, is there a reproducer perhaps? Is there some class file i could 
> > > > run with specific parameters to reproduce it?
> > > 
> > > I'll try this with some java benchmarks we have, AMQP related, lets see
> > > if I can reproduce it.
> > 
> > I tried this with SPECJbb - which I am not at liberty to distribute
> > unfortunately. I will try and recreate it with volanomark or other open
> > source benchmarks.
> 
> I could indeed reproduce with vmark. Am poking at it.. still clueless
> though ;-)

[root@opteron tmp]# cat foo.c
#include <pthread.h>
#include <unistd.h>

void *thread(void *arg)
{
        sleep(5);
        return NULL;
}

void main(void)
{
        pthread_t thr;
        pthread_create(&thr, NULL, thread, NULL);
}

The above instantly triggers it. It appears we fail to cleanup on the
reparent path. I'll go root around in exit.c.