Commit-ID: fbfc623f8231c8d8c78aab5841e9c6e5811ab638
Gitweb: http://git.kernel.org/tip/fbfc623f8231c8d8c78aab5841e9c6e5811ab638
Author: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
AuthorDate: Fri, 15 Jun 2012 14:31:31 +0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 18 Jun 2012 12:13:20 +0200
perf: Avoid race between cpu hotplug and installing event
perf_event_open() requires the cpu on which to install event is online,
but the cpu can go offline after perf_event_open checks that. Add a
get_online_cpus()/put_online_cpus() pair to avoid the race.
Signed-off-by: Zheng Yan <zheng.z.yan@xxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1339741902-8449-3-git-send-email-zheng.z.yan@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d7d71d6..31d182e 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6252,6 +6252,8 @@ SYSCALL_DEFINE5(perf_event_open,
}
}
+ get_online_cpus();
+
event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
NULL, NULL);
if (IS_ERR(event)) {
@@ -6391,6 +6393,8 @@ SYSCALL_DEFINE5(perf_event_open,
perf_unpin_context(ctx);
mutex_unlock(&ctx->mutex);
+ put_online_cpus();
+
event->owner = current;
mutex_lock(¤t->perf_event_mutex);
@@ -6419,6 +6423,7 @@ err_context:
err_alloc:
free_event(event);
err_task:
+ put_online_cpus();
if (task)
put_task_struct(task);
err_group_fd:
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|