Re: [PATCH v2] perf: Synchronously cleanup child events

[Peter Zijlstra]

On Wed, Jan 20, 2016 at 09:04:28AM +0200, Alexander Shishkin wrote:
> Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes:

> > The most obvious place that generates such magical references would be
> > the bpf arraymap doing perf_event_get() on things. There are a few other
> > places that take temp references (perf_mmap_close), but those are
> > 'short' lived and while ugly will not cause massive grief.
> 
> We won't get to perf_release() before we're done with perf_mmap_close(),
> so that one's not really a problem.

Only for the file we mmap()'ed, the events we've attached through
IOC_SET_OUTPUT will not have a file reference from the mmap().