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-rw-r--r--kernel/perf_event.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index b0feb47..96aae13 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3376,15 +3376,23 @@ static void perf_event_task_output(struct perf_event *event,
struct perf_task_event *task_event)
{
struct perf_output_handle handle;
- int size;
struct task_struct *task = task_event->task;
- int ret;
+ unsigned long flags;
+ int size, ret;
+
+ /*
+ * If this CPU attempts to acquire an rq lock held by a CPU spinning
+ * in perf_output_lock() from interrupt context, it's game over.
+ */
+ local_irq_save(flags);
size = task_event->event_id.header.size;
ret = perf_output_begin(&handle, event, size, 0, 0);
- if (ret)
+ if (ret) {
+ local_irq_restore(flags);
return;
+ }
task_event->event_id.pid = perf_event_pid(event, task);
task_event->event_id.ppid = perf_event_pid(event, current);
@@ -3395,6 +3403,7 @@ static void perf_event_task_output(struct perf_event *event,
perf_output_put(&handle, task_event->event_id);
perf_output_end(&handle);
+ local_irq_restore(flags);
}
static int perf_event_task_match(struct perf_event *event)
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