Messages in this thread | | | Date | Thu, 7 Mar 2019 16:03:30 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf/core: restore mmap record type correctly |
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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?
- Arnaldo
> Signed-off-by: Stephane Eranian <eranian@google.com> > --- > kernel/events/core.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 5f59d848171e..f170cd12beed 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -7188,6 +7188,7 @@ static void perf_event_mmap_output(struct perf_event *event, > struct perf_output_handle handle; > struct perf_sample_data sample; > int size = mmap_event->event_id.header.size; > + u32 type = mmap_event->event_id.header.type; > int ret; > > if (!perf_event_mmap_match(event, data)) > @@ -7231,6 +7232,7 @@ static void perf_event_mmap_output(struct perf_event *event, > perf_output_end(&handle); > out: > mmap_event->event_id.header.size = size; > + mmap_event->event_id.header.type = type; > } > > static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) > -- > 2.21.0.360.g471c308f928-goog
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