Re: Crashes in perf_event_ctx_lock_nested

Thomas Gleixner
2017-11-01T08:27:08Z

On Wed, 1 Nov 2017, Peter Zijlstra wrote:

> On Tue, Oct 31, 2017 at 10:32:00PM +0100, Thomas Gleixner wrote:
> > That means we can have the following situation:
> >
> > lock(watchdog_mutex);
> > lockup_detector_reconfigure();
> > cpus_read_lock();
> > stop();
> > park()
> > update();
> > start();
> > unpark()
> > cpus_read_unlock(); thread runs()
> > cleanup();
> > unlock(watchdog_mutex);
> >
>
> Isn't there also a where hardlockup_detector_perf_init() creates an
> event to 'probe' stuff, and then hardlockup_detector_perf_enable()
> _again_ creates the event?

probe() releases the event.