Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

  * Don't try to find DSOs in SYSV maps (Don Zickus)

  * Fallback to MAP__FUNCTION if daddr maps are NULL,
    i.e. addresses get looked upon more maps (Don Zickus)

  * Kernel fix to properly handle exited tasks, by returning POLLHUP values
    on perf event file descriptors. Tooling changes will come next, but were
    tested with this kernel fix. (Jiri Olsa)

  * Add +field argument support for --field option, so that one can add
    fields to the default list of fields to show, i.e. now one can just do:

     perf report --fields +pid

    And the pid will appear in addition to the default fields. (Jiri Olsa)

Infrastructure changes:

  * More Intel PT prep stuff, including:
    - Add a 'perf test' for tracking with sched_switch
    - Add 'flush' callback to scripting API

  * hists browser (used in top and report) refactorings, getting rid of unused
    variables and reducing source code size by handling similar cases in a
    fewer functions (Namhyung Kim).

  * Explicitly include util/debug.h for powerpc, was being indirectly included,
    broke the build when some change made it stop being included. (Sukadev
    Bhattiprolu)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2d7363adf678..d8cb4d21a346 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3600,7 +3600,8 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
 	 * error state (i.e. because it was pinned but it couldn't be
 	 * scheduled on to the CPU at some point).
 	 */
-	if (event->state == PERF_EVENT_STATE_ERROR)
+	if ((event->state == PERF_EVENT_STATE_ERROR) ||
+	    (event->state == PERF_EVENT_STATE_EXIT))
 		return 0;
 
 	if (count < event->read_size)
@@ -3627,9 +3628,13 @@ static unsigned int perf_poll(struct file *file, poll_table *wait)
 {
 	struct perf_event *event = file->private_data;
 	struct ring_buffer *rb;
-	unsigned int events = POLL_HUP;
+	unsigned int events = POLLHUP;
 
 	poll_wait(file, &event->waitq, wait);
+
+	if (event->state == PERF_EVENT_STATE_EXIT)
+		return events;
+
 	/*
 	 * Pin the event->rb by taking event->mmap_mutex; otherwise
 	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
@@ -7588,6 +7593,9 @@ __perf_event_exit_task(struct perf_event *child_event,
 	if (child_event->parent) {
 		sync_child_event(child_event, child);
 		free_event(child_event);
+	} else {
+		child_event->state = PERF_EVENT_STATE_EXIT;
+		perf_event_wakeup(child_event);
 	}
 }