[PATCH 2/2] perf tools: Ignore dead threads during event synthesis

Namhyung Kim
2022-07-01T20:55:11Z

When it synthesize various task events, it scans the list of task
first and then accesses later. There's a window threads can die
between the two and proc entries may not be available.

Instead of bailing out, we can ignore that thread and move on.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/util/synthetic-events.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index a068f42833c3..84d17bd4efae 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -767,11 +767,12 @@ static int __event__synthesize_thread(union perf_event *comm_event,
if (*end)
continue;

- rc = -1;
+ /* some threads may exit just after scan, ignore it */
if (perf_event__prepare_comm(comm_event, pid, _pid, machine,
&tgid, &ppid, &kernel_thread) != 0)
- break;
+ continue;

+ rc = -1;
if (perf_event__synthesize_fork(tool, fork_event, _pid, tgid,
ppid, process, machine) < 0)
break;
--
2.37.0.rc0.161.g10f37bed90-goog