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authorYan, Zheng <zheng.z.yan@intel.com>2012-06-15 14:31:31 +0800
committerIngo Molnar <mingo@kernel.org>2012-06-18 12:13:20 +0200
commitfbfc623f8231c8d8c78aab5841e9c6e5811ab638 (patch)
tree54883756f1b404f2232d4d5077219ea98c1fdbfd /kernel/events
parent4b4969b14490a4f65b572b8f180164181104b5e1 (diff)
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@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1339741902-8449-3-git-send-email-zheng.z.yan@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d7d71d6ec972..31d182e01549 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(&current->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: