[tip:perf/urgent] perf: Fix orphan hole

[tip-bot for Peter Zijlstra <tipbot@xxxxxxxxx>]

Commit-ID:  78cd2c748f459739ff864dd9308c0f6caf7f6e41
Gitweb:     http://git.kernel.org/tip/78cd2c748f459739ff864dd9308c0f6caf7f6e41
Author:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 25 Jan 2016 14:08:45 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 28 Jan 2016 20:06:35 +0100

perf: Fix orphan hole

We should set event->owner before we install the event,
otherwise there is a hole where the target task can fork() and
we'll not inherit the event because it thinks the event is
orphaned.

Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/events/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9de4d35..6759f2a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8489,6 +8489,8 @@ SYSCALL_DEFINE5(perf_event_open,
 	perf_event__header_size(event);
 	perf_event__id_header_size(event);
 
+	event->owner = current;
+
 	perf_install_in_context(ctx, event, event->cpu);
 	perf_unpin_context(ctx);
 
@@ -8498,8 +8500,6 @@ SYSCALL_DEFINE5(perf_event_open,
 
 	put_online_cpus();
 
-	event->owner = current;
-
 	mutex_lock(&current->perf_event_mutex);
 	list_add_tail(&event->owner_entry, &current->perf_event_list);
 	mutex_unlock(&current->perf_event_mutex);
--
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