Messages in this thread | | | Date | Mon, 25 Jan 2016 12:48:46 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2] perf: Synchronously cleanup child events |
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On Fri, Jan 22, 2016 at 11:44:03AM -0800, Alexei Starovoitov wrote: > On Fri, Jan 22, 2016 at 01:38:47PM +0100, Peter Zijlstra wrote: > > On Fri, Jan 22, 2016 at 01:35:40PM +0200, Alexander Shishkin wrote: > > > Peter Zijlstra <peterz@infradead.org> writes: > > > > > > > So I think there's a number of problems still :-( > > I've been looking at how perf_event->owner is handled and couldn't > figure out how you deal with the case of passing perf_event_fd via scm_rights. > It seems one process can open an event, pass it to another process, > but when current process exists owner will still point to dead task, > since refcount > 0. > Which part am I missing?
Nothing, you raised a good point. I think this shows we cannot link !event->owner to an event being 'dead'.
If we keep these two states separate, the scm_rights thing should work again.
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