lkml.org 
[lkml]   [2016]   [Jan]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [tip:perf/urgent] perf: Fix perf_event_exit_task() race

---

Subject: perf: Fix orphan hole
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri Jan 22 22:13:41 CET 2016

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 (Intel) <peterz@infradead.org>
---
kernel/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- 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);
\
 
 \ /
  Last update: 2016-01-25 14:21    [W:0.142 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site