Commit e5bed564 authored Sep 30, 2015 by Namhyung Kim Committed by Arnaldo Carvalho de Melo Oct 01, 2015

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>

parent c2365b93

tools/perf/builtin-record.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}

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