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AJvYcCU/57IRtpFamQ0Q1uFJVp6gn4k0uecP7GG4h+W20vS6DweZQO/K4Nk2hTc48KZLLgMmHKYLb+T0Rnh599jbHBsH@vger.kernel.org X-Gm-Message-State: AOJu0YxEpGi6SoN8IXG2iNMxOKUFbOUVEAzVz+wJJsfSbxDkt9aP3Cjg n4b6WX+AxGVVGfcgXIkmiL91iMy5wqf++qflGfNlihr8HJ91PaS4+i1NFb6S2IIbofnTKExMZo/ qKKUaBLrppA== X-Google-Smtp-Source: AGHT+IE2ixd/IZtDfy0s9qwtIYYwndIgI/TKU5XqnZAyvxDPYGq4ceG0lTr5ap0cGswGY9kMhS/jNXjv+XTN X-Received: from pjbsw8.prod.google.com ([2002:a17:90b:2c88:b0:311:b186:430c]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90a:fc4e:b0:2ff:5357:1c7e with SMTP id 98e67ed59e1d1-311100da2c8mr20426074a91.20.1748402808499; Tue, 27 May 2025 20:26:48 -0700 (PDT) Date: Tue, 27 May 2025 20:26:34 -0700 In-Reply-To: <20250528032637.198960-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250528032637.198960-1-irogers@google.com> X-Mailer: git-send-email 2.49.0.1238.gf8c92423fb-goog Message-ID: <20250528032637.198960-5-irogers@google.com> Subject: [PATCH v2 4/7] perf intel-tpebs: Avoid race when evlist is being deleted From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , "=?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?=" , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jiapeng Chong , James Clark , Howard Chu , Weilin Wang , Stephen Brennan , Andi Kleen , Dmitry Vyukov , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Reading through the evsel->evlist may seg fault if a sample arrives when the evlist is being deleted. Detect this case and ignore samples arriving when the evlist is being deleted. Fixes: bcfab08db7fb ("perf intel-tpebs: Filter non-workload samples") Signed-off-by: Ian Rogers --- tools/perf/util/intel-tpebs.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/intel-tpebs.c b/tools/perf/util/intel-tpebs.c index 4ad4bc118ea5..3b92ebf5c112 100644 --- a/tools/perf/util/intel-tpebs.c +++ b/tools/perf/util/intel-tpebs.c @@ -162,9 +162,17 @@ static bool is_child_pid(pid_t parent, pid_t child) static bool should_ignore_sample(const struct perf_sample *sample, const struct tpebs_retire_lat *t) { - pid_t workload_pid = t->evsel->evlist->workload.pid; - pid_t sample_pid = sample->pid; + pid_t workload_pid, sample_pid = sample->pid; + /* + * During evlist__purge the evlist will be removed prior to the + * evsel__exit calling evsel__tpebs_close and taking the + * tpebs_mtx. Avoid a segfault by ignoring samples in this case. + */ + if (t->evsel->evlist == NULL) + return true; + + workload_pid = t->evsel->evlist->workload.pid; if (workload_pid < 0 || workload_pid == sample_pid) return false; -- 2.49.0.1238.gf8c92423fb-goog