Commit-ID: 5cb73340d92a716fd2776700742c3558206ae298 Gitweb: http://git.kernel.org/tip/5cb73340d92a716fd2776700742c3558206ae298 Author: Adrian Hunter <adrian.hun...@intel.com> AuthorDate: Wed, 19 Aug 2015 17:29:20 +0300 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Wed, 19 Aug 2015 14:15:25 -0300
perf tools: Make fork event processing more resilient When processing a fork event, the tools lookup the parent thread by its tid. In a couple of cases, it is possible for that thread to have the wrong pid. That can happen if the data is being processed out of order, or if the (fork) event that would have removed the erroneous thread was lost. Assume the latter case, print a dump message, remove the erroneous thread, create a new one with the correct pid, and keep going. Reported-by: Arnaldo Carvalho de Melo <a...@redhat.com> Signed-off-by: Adrian Hunter <adrian.hun...@intel.com> Tested-by: Jiri Olsa <jo...@kernel.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Link: http://lkml.kernel.org/r/1439994561-27436-3-git-send-email-adrian.hun...@intel.com Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/util/machine.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 7ff6827..f1a4c83 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -1387,6 +1387,24 @@ int machine__process_fork_event(struct machine *machine, union perf_event *event event->fork.ptid); int err = 0; + if (dump_trace) + perf_event__fprintf_task(event, stdout); + + /* + * There may be an existing thread that is not actually the parent, + * either because we are processing events out of order, or because the + * (fork) event that would have removed the thread was lost. Assume the + * latter case and continue on as best we can. + */ + if (parent->pid_ != (pid_t)event->fork.ppid) { + dump_printf("removing erroneous parent thread %d/%d\n", + parent->pid_, parent->tid); + machine__remove_thread(machine, parent); + thread__put(parent); + parent = machine__findnew_thread(machine, event->fork.ppid, + event->fork.ptid); + } + /* if a thread currently exists for the thread id remove it */ if (thread != NULL) { machine__remove_thread(machine, thread); @@ -1395,8 +1413,6 @@ int machine__process_fork_event(struct machine *machine, union perf_event *event thread = machine__findnew_thread(machine, event->fork.pid, event->fork.tid); - if (dump_trace) - perf_event__fprintf_task(event, stdout); if (thread == NULL || parent == NULL || thread__fork(thread, parent, sample->time) < 0) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
