Commit-ID:  46fb3c21d20415dd2693570c33d0ea6eb8745e04
Gitweb:     http://git.kernel.org/tip/46fb3c21d20415dd2693570c33d0ea6eb8745e04
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Mon, 22 Sep 2014 14:39:48 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Thu, 25 Sep 2014 16:46:56 -0300

perf trace: Filter out POLLHUP'ed file descriptors

So that we don't continue polling on vanished file descriptors, i.e.
file descriptors for events monitoring threads that exited.

I.e. the following 'trace' command now exits as expected, instead
of staying in an eternal loop:

      $ sleep 5s &
      $ trace -p `pidof sleep`

Reported-by: Jiri Olsa <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Don Zickus <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
 tools/perf/builtin-trace.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index b8fedf3..fe39dc6 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2044,6 +2044,7 @@ static int trace__run(struct trace *trace, int argc, 
const char **argv)
        int err = -1, i;
        unsigned long before;
        const bool forks = argc > 0;
+       bool draining = false;
        char sbuf[STRERR_BUFSIZE];
 
        trace->live = true;
@@ -2171,8 +2172,12 @@ next_event:
        if (trace->nr_events == before) {
                int timeout = done ? 100 : -1;
 
-               if (perf_evlist__poll(evlist, timeout) > 0)
+               if (!draining && perf_evlist__poll(evlist, timeout) > 0) {
+                       if (perf_evlist__filter_pollfd(evlist, POLLERR | 
POLLHUP) == 0)
+                               draining = true;
+
                        goto again;
+               }
        } else {
                goto again;
        }
--
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