When it fails to open events record__open() returns without setting the
session->evlist. Then it gets a segfault in the function trying to read
lost sample counts. You can easily reproduce it as a normal user like:
$ perf record -p 1 true
...
perf: Segmentation fault
...
Skip the function if it has no evlist. And add more protection for evsels
which are not properly initialized.
Fixes:
a49aa8a54e861af1 ("perf record: Read and inject LOST_SAMPLES events")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Leo Yan <leo.yan@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20220909235024.278281-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
struct perf_record_lost_samples *lost;
struct evsel *evsel;
+ /* there was an error during record__open */
+ if (session->evlist == NULL)
+ return;
+
lost = zalloc(PERF_SAMPLE_MAX_SIZE);
if (lost == NULL) {
pr_debug("Memory allocation failed\n");
evlist__for_each_entry(session->evlist, evsel) {
struct xyarray *xy = evsel->core.sample_id;
+ if (xy == NULL || evsel->core.fd == NULL)
+ continue;
if (xyarray__max_x(evsel->core.fd) != xyarray__max_x(xy) ||
xyarray__max_y(evsel->core.fd) != xyarray__max_y(xy)) {
pr_debug("Unmatched FD vs. sample ID: skip reading LOST count\n");