Messages in this thread | | | Date | Thu, 7 Mar 2019 20:09:39 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] perf/core: restore mmap record type correctly |
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On Thu, Mar 07, 2019 at 04:03:30PM -0300, Arnaldo Carvalho de Melo wrote: > Em Thu, Mar 07, 2019 at 10:52:33AM -0800, Stephane Eranian escreveu: > > On mmap(), perf_events generates a RECORD_MMAP record and then checks > > which events are interested in this record. There are currently 2 versions > > of mmap records: RECORD_MMAP and RECORD_MMAP2. MMAP2 is larger. The event > > configuration controls which version the user level tool accepts. If the > > event->attr.mmap2=1 field then MMAP2 record is returned. The > > perf_event_mmap_output() takes care of this. It checks attr->mmap2 and corrects > > the record fields before putting it in the sampling buffer of the event. > > At the end the function restores the modified MMAP record fields. > > > > The problem is that the function restores the size but not the > > type. Thus, if a subsequent event only accepts MMAP type, then it would > > instead receive an MMAP2 record with a size of MMAP record. > > > > This patch fixes the problem by restoring the record type on exit. > > Right, simple enough, bug fixed, Peter, I'm taking this one, ok?
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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