Re: Crashes in perf_event_ctx_lock_nested

Peter Zijlstra
2017-11-01T08:14:59Z

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?