From: Jin Yao yao.jin@linux.intel.com
[ Upstream commit 8510895bafdbf7c4dd24c22946d925691135c2b2 ]
A big uncore event group is split into multiple small groups which only include the uncore events from the same PMU. This has been supported in the commit 3cdc5c2cb924a ("perf parse-events: Handle uncore event aliases in small groups properly").
If the event's PMU name starts to repeat, it must be a new event. That can be used to distinguish the leader from other members. But now it only compares the pointer of pmu_name (leader->pmu_name == evsel->pmu_name).
If we use "perf stat -M LLC_MISSES.PCIE_WRITE -a" on cascadelakex, the event list is:
evsel->name evsel->pmu_name --------------------------------------------------------------- unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_4 (as leader) unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_2 unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_0 unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_5 unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_3 unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_1 unc_iio_data_req_of_cpu.mem_write.part1 uncore_iio_4 ......
For the event "unc_iio_data_req_of_cpu.mem_write.part1" with "uncore_iio_4", it should be the event from PMU "uncore_iio_4". It's not a new leader for this PMU.
But if we use "(leader->pmu_name == evsel->pmu_name)", the check would be failed and the event is stored to leaders[] as a new PMU leader.
So this patch uses strcmp to compare the PMU name between events.
Fixes: d4953f7ef1a2 ("perf parse-events: Fix 3 use after frees found with clang ASAN") Signed-off-by: Jin Yao yao.jin@linux.intel.com Acked-by: Jiri Olsa jolsa@redhat.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andi Kleen ak@linux.intel.com Cc: Jin Yao yao.jin@intel.com Cc: Kan Liang kan.liang@linux.intel.com Cc: Peter Zijlstra peterz@infradead.org Link: http://lore.kernel.org/lkml/20200430003618.17002-1-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/parse-events.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -1505,12 +1505,11 @@ parse_events__set_leader_for_uncore_alia * event. That can be used to distinguish the leader from * other members, even they have the same event name. */ - if ((leader != evsel) && (leader->pmu_name == evsel->pmu_name)) { + if ((leader != evsel) && + !strcmp(leader->pmu_name, evsel->pmu_name)) { is_leader = false; continue; } - /* The name is always alias name */ - WARN_ON(strcmp(leader->name, evsel->name));
/* Store the leader event for each PMU */ leaders[nr_pmu++] = (uintptr_t) evsel;