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AFNElJ+nbrN4fkW+jTrFQ4yxDRh622ZNYNgKpprPfZVbqrry2E992OJqbODS0XbCU+Xx8+p3pyR+m8xY2lVw2K40j45J@vger.kernel.org X-Gm-Message-State: AOJu0Yw7XDxYBugbEnRBZnzR4+hL6cWYW/Q/2SdOsQLkvt3s2NQlMLiL 7zkXwWblmh1bQEhAZBsLwnP3rkCEDPW/m0bUX+POrWIjsO2O68uQDSPHcRGezu3GjIHE4GWXrbo rT2HN9GQ0oQ== X-Received: from dybmi9.prod.google.com ([2002:a05:7301:f89:b0:2f9:af7:5053]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7300:dc17:b0:2ed:e12:376c with SMTP id 5a478bee46e88-303986bbe04mr11583793eec.34.1779303990974; Wed, 20 May 2026 12:06:30 -0700 (PDT) Date: Wed, 20 May 2026 12:05:29 -0700 In-Reply-To: <20260520190538.142018-1-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: <20260512223001.2952848-1-irogers@google.com> <20260520190538.142018-1-irogers@google.com> X-Mailer: git-send-email 2.54.0.746.g67dd491aae-goog Message-ID: <20260520190538.142018-24-irogers@google.com> Subject: [PATCH v14 23/32] perf lock: Avoid segv if event is missing a callchain From: Ian Rogers To: irogers@google.com, acme@kernel.org, namhyung@kernel.org Cc: adrian.hunter@intel.com, ajones@ventanamicro.com, ak@linux.intel.com, alex@ghiti.fr, alexander.shishkin@linux.intel.com, anup@brainfault.org, aou@eecs.berkeley.edu, atrajeev@linux.ibm.com, blakejones@google.com, ctshao@google.com, dapeng1.mi@linux.intel.com, derek.foreman@collabora.com, dvyukov@google.com, howardchu95@gmail.com, hrishikesh123s@gmail.com, james.clark@linaro.org, jolsa@kernel.org, krzysztof.m.lopatowski@gmail.com, leo.yan@arm.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux@treblig.org, mingo@redhat.com, nichen@iscas.ac.cn, palmer@dabbelt.com, peterz@infradead.org, pjw@kernel.org, ravi.bangoria@amd.com, swapnil.sapkal@amd.com, tanze@kylinos.cn, thomas.falcon@intel.com, tianyou.li@intel.com, yujie.liu@intel.com, zhouquan@iscas.ac.cn Content-Type: text/plain; charset="UTF-8" Avoid a potential segmentation fault if a parsed sample unexpectedly lacks a valid callchain pointer. Add a check for a NULL sample->callchain pointer in get_callstack(). If the callchain is missing, return NULL to safely skip the event and log a debug warning rather than causing a tool segfault. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim --- tools/perf/builtin-lock.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c index 89a40d385b27..064b3aa4bad7 100644 --- a/tools/perf/builtin-lock.c +++ b/tools/perf/builtin-lock.c @@ -938,9 +938,16 @@ static u64 *get_callstack(struct perf_sample *sample, int max_stack) u64 i; int c; + if (!sample->callchain) { + pr_debug("Sample unexpectedly missing callchain\n"); + return NULL; + } + callstack = calloc(max_stack, sizeof(*callstack)); - if (callstack == NULL) + if (callstack == NULL) { + pr_debug("Failed to allocate callstack\n"); return NULL; + } for (i = 0, c = 0; i < sample->callchain->nr && c < max_stack; i++) { u64 ip = sample->callchain->ips[i]; @@ -1059,7 +1066,7 @@ static int report_lock_contention_begin_event(struct perf_sample *sample) if (needs_callstack()) { u64 *callstack = get_callstack(sample, max_stack_depth); if (callstack == NULL) - return -ENOMEM; + return 0; if (!match_callstack_filter(machine, callstack, max_stack_depth)) { free(callstack); -- 2.54.0.746.g67dd491aae-goog