perf record: Allocate area for sample_id_hdr in a synthesized comm event

A previous patch added a synthesized comm event for forked child process
but it missed that the event should contain area for sample_id_hdr at
the end.  It worked by accident since the perf_event union contains
bigger event structs like mmap_events.

This patch fixes it by dynamically allocating event struct including
those area like in perf_event__synthesize_thread_map().

Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1443577526-3240-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2015-09-30 10:45:24 +09:00 committed by Arnaldo Carvalho de Melo
parent c2365b9388
commit e5bed56448

View File

@ -637,17 +637,25 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
* Let the child rip
*/
if (forks) {
union perf_event event;
union perf_event *event;
event = malloc(sizeof(event->comm) + machine->id_hdr_size);
if (event == NULL) {
err = -ENOMEM;
goto out_child;
}
/*
* Some H/W events are generated before COMM event
* which is emitted during exec(), so perf script
* cannot see a correct process name for those events.
* Synthesize COMM event to prevent it.
*/
perf_event__synthesize_comm(tool, &event,
perf_event__synthesize_comm(tool, event,
rec->evlist->workload.pid,
process_synthesized_event,
machine);
free(event);
perf_evlist__start_workload(rec->evlist);
}