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From: Namhyung Kim <namhyung@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>, Jiri Olsa <jolsa@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	linux-perf-users@vger.kernel.org,
	Song Liu <songliubraving@fb.com>,
	bpf@vger.kernel.org
Subject: [PATCH 3/4] perf stat: Use evsel->core.cpus to iterate cpus in BPF cgroup counters
Date: Fri, 16 Sep 2022 11:41:31 -0700	[thread overview]
Message-ID: <20220916184132.1161506-4-namhyung@kernel.org> (raw)
In-Reply-To: <20220916184132.1161506-1-namhyung@kernel.org>

If it mixes core and uncore events, each evsel would have different cpu map.
But it assumed they are same with evlist's all_cpus and accessed by the same
index.  This resulted in a crash like below.

  $ perf stat -a --bpf-counters --for-each_cgroup ^. -e cycles,imc/cas_count_read/ sleep 1
  Segmentation fault

While it's not recommended to use uncore events for cgroup aggregation, it
should not crash.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/bpf_counter_cgroup.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/bpf_counter_cgroup.c b/tools/perf/util/bpf_counter_cgroup.c
index 97c69a249c6e..3c2df7522f6f 100644
--- a/tools/perf/util/bpf_counter_cgroup.c
+++ b/tools/perf/util/bpf_counter_cgroup.c
@@ -115,14 +115,14 @@ static int bperf_load_program(struct evlist *evlist)
 			evsel->cgrp = NULL;
 
 			/* open single copy of the events w/o cgroup */
-			err = evsel__open_per_cpu(evsel, evlist->core.all_cpus, -1);
+			err = evsel__open_per_cpu(evsel, evsel->core.cpus, -1);
 			if (err) {
 				pr_err("Failed to open first cgroup events\n");
 				goto out;
 			}
 
 			map_fd = bpf_map__fd(skel->maps.events);
-			perf_cpu_map__for_each_cpu(cpu, j, evlist->core.all_cpus) {
+			perf_cpu_map__for_each_cpu(cpu, j, evsel->core.cpus) {
 				int fd = FD(evsel, j);
 				__u32 idx = evsel->core.idx * total_cpus + cpu.cpu;
 
@@ -269,7 +269,7 @@ static int bperf_cgrp__read(struct evsel *evsel)
 			goto out;
 		}
 
-		perf_cpu_map__for_each_cpu(cpu, i, evlist->core.all_cpus) {
+		perf_cpu_map__for_each_cpu(cpu, i, evsel->core.cpus) {
 			counts = perf_counts(evsel->counts, i, 0);
 			counts->val = values[cpu.cpu].counter;
 			counts->ena = values[cpu.cpu].enabled;
-- 
2.37.3.968.ga6b4b080e4-goog


  parent reply	other threads:[~2022-09-16 18:41 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-16 18:41 [PATCH 0/4] perf stat: Fix bperf cgroup counters (v2) Namhyung Kim
2022-09-16 18:41 ` [PATCH 1/4] perf stat: Fix BPF program section name Namhyung Kim
2022-09-16 18:41 ` [PATCH 2/4] perf stat: Fix cpu map index in bperf cgroup code Namhyung Kim
2022-09-16 18:41 ` Namhyung Kim [this message]
2022-09-16 18:41 ` [PATCH 4/4] perf test: Add a new test for perf stat cgroup BPF counter Namhyung Kim
2022-09-20 19:53 ` [PATCH 0/4] perf stat: Fix bperf cgroup counters (v2) Arnaldo Carvalho de Melo

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