On Thu, Jan 21, 2021 at 12:18:38AM +0800, John Garry wrote:
> Metrics containing duration_time cause a segfault:
>
> $./perf stat -v -M L1D_Cache_Fill_BW sleep 1
> Using CPUID GenuineIntel-6-3D-4
> metric expr 64 * l1d.replacement / 1000000000 / duration_time for
> L1D_Cache_Fill_BW
> found event duration_time
> found event l1d.replacement
> adding {l1d.replacement}:W,duration_time
> l1d.replacement -> cpu/umask=0x1,(null)=0x1e8483,event=0x51/
> Segmentation fault
>
> In commit c2337d67199a ("perf metricgroup: Fix metrics using aliases
> covering multiple PMUs"), the logic in find_evsel_group() when iter'ing
> events was changed to not only select events in same group, but also for
> aliased PMUs.
>
> Checking whether events were for aliased PMUs was done by comparing the
> event PMU name. This was not safe for duration_time event, which has no
> associated PMU (and no PMU name), so fix by checking if the event PMU name
> is set also.
>
> Fixes: c2337d67199a ("perf metricgroup: Fix metrics using aliases covering
> multiple PMUs")
> Reported-by: Joakim Zhang <[email protected]>
> Signed-off-by: John Garry <[email protected]>
Tested/Acked-by: Jiri Olsa <[email protected]>
thanks,
jirka
>
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index 2e60ee170abc..e6d3452031e5 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -162,6 +162,14 @@ static bool contains_event(struct evsel **metric_events,
> int num_events,
> return false;
> }
>
> +static bool evsel_same_pmu(struct evsel *ev1, struct evsel *ev2)
> +{
> + if (!ev1->pmu_name || !ev2->pmu_name)
> + return false;
> +
> + return !strcmp(ev1->pmu_name, ev2->pmu_name);
> +}
> +
> /**
> * Find a group of events in perf_evlist that correspond to those from a
> parsed
> * metric expression. Note, as find_evsel_group is called in the same order
> as
> @@ -280,8 +288,7 @@ static struct evsel *find_evsel_group(struct evlist
> *perf_evlist,
> */
> if (!has_constraint &&
> ev->leader != metric_events[i]->leader &&
> - !strcmp(ev->leader->pmu_name,
> - metric_events[i]->leader->pmu_name))
> + evsel_same_pmu(ev->leader,
> metric_events[i]->leader))
> break;
> if (!strcmp(metric_events[i]->name, ev->name)) {
> set_bit(ev->idx, evlist_used);
> --
> 2.26.2
>
