6.12-stable review patch. If anyone has any objections, please let me know.
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From: James Clark james.clark@linaro.org
[ Upstream commit c9d699e10fa6c0cdabcddcf991e7ff42af6b2503 ]
After pmu_add_cpu_aliases() is called, perf_pmu__num_events() returns an incorrect value that double counts common events and doesn't match the actual count of events in the alias list. This is because after 'cpu_aliases_added == true', the number of events returned is 'sysfs_aliases + cpu_json_aliases'. But when adding 'case EVENT_SRC_SYSFS' events, 'sysfs_aliases' and 'cpu_json_aliases' are both incremented together, failing to account that these ones overlap and only add a single item to the list. Fix it by adding another counter for overlapping events which doesn't influence 'cpu_json_aliases'.
There doesn't seem to be a current issue because it's used in perf list before pmu_add_cpu_aliases() so the correct value is returned. Other uses in tests may also miss it for other reasons like only looking at uncore events. However it's marked as a fixes commit in case any new fix with new uses of perf_pmu__num_events() is backported.
Fixes: d9c5f5f94c2d ("perf pmu: Count sys and cpuid JSON events separately") Reviewed-by: Ian Rogers irogers@google.com Signed-off-by: James Clark james.clark@linaro.org Link: https://lore.kernel.org/r/20250226104111.564443-3-james.clark@linaro.org Signed-off-by: Namhyung Kim namhyung@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/pmu.c | 7 ++++--- tools/perf/util/pmu.h | 5 +++++ 2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index ed893c3c6ad93..8b4e346808b4c 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -593,7 +593,7 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name, }; if (pmu_events_table__find_event(pmu->events_table, pmu, name, update_alias, &data) == 0) - pmu->cpu_json_aliases++; + pmu->cpu_common_json_aliases++; } pmu->sysfs_aliases++; break; @@ -1807,9 +1807,10 @@ size_t perf_pmu__num_events(struct perf_pmu *pmu) if (pmu->cpu_aliases_added) nr += pmu->cpu_json_aliases; else if (pmu->events_table) - nr += pmu_events_table__num_events(pmu->events_table, pmu) - pmu->cpu_json_aliases; + nr += pmu_events_table__num_events(pmu->events_table, pmu) - + pmu->cpu_common_json_aliases; else - assert(pmu->cpu_json_aliases == 0); + assert(pmu->cpu_json_aliases == 0 && pmu->cpu_common_json_aliases == 0);
return pmu->selectable ? nr + 1 : nr; } diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index 4397c48ad569a..bcd278b9b546f 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -131,6 +131,11 @@ struct perf_pmu { uint32_t cpu_json_aliases; /** @sys_json_aliases: Number of json event aliases loaded matching the PMU's identifier. */ uint32_t sys_json_aliases; + /** + * @cpu_common_json_aliases: Number of json events that overlapped with sysfs when + * loading all sysfs events. + */ + uint32_t cpu_common_json_aliases; /** @sysfs_aliases_loaded: Are sysfs aliases loaded from disk? */ bool sysfs_aliases_loaded; /**