On Thu, Mar 7, 2019 at 11:26 AM Arnaldo Carvalho de Melo <[email protected]> wrote: > > Em Thu, Mar 07, 2019 at 08:09:39PM +0100, Peter Zijlstra escreveu: > > 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) <[email protected]> > > BTW, added: > > Fixes: 13d7a2410fa6 ("perf: Add attr->mmap2 attribute to an event") > > For the stable guys to pick this up. Please try to add the fixes tag in > the future.
Ok, thanks. > > > Thanks, > > - Arnaldo
