tracing: Fix race in snapshot swapping

[pandora-kernel.git] / kernel / trace / trace.c

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5638104..262d9df 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -652,7 +652,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 void
 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
-       struct ring_buffer *buf = tr->buffer;
+       struct ring_buffer *buf;
 
        if (trace_stop_count)
                return;
@@ -664,6 +664,7 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
        }
        arch_spin_lock(&ftrace_max_lock);
 
+       buf = tr->buffer;
        tr->buffer = max_tr.buffer;
        max_tr.buffer = buf;