---

yaml
---
r: 121309
b: refs/heads/master
c: 98db8df
h: refs/heads/master
i:
  121307: e3f9df0
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a8ccf1d6f60e3e6ae63122e02378cd4d40dd4aac
+refs/heads/master: 98db8df777438e16ad0f44a0fba05ebbdb73db8d

trunk/kernel/trace/ring_buffer.c

@@ -962,12 +962,15 @@ static struct ring_buffer_event *
 __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 		  unsigned type, unsigned long length, u64 *ts)
 {
-	struct buffer_page *tail_page, *head_page, *reader_page;
+	struct buffer_page *tail_page, *head_page, *reader_page, *commit_page;
 	unsigned long tail, write;
 	struct ring_buffer *buffer = cpu_buffer->buffer;
 	struct ring_buffer_event *event;
 	unsigned long flags;
 
+	commit_page = cpu_buffer->commit_page;
+	/* we just need to protect against interrupts */
+	barrier();
 	tail_page = cpu_buffer->tail_page;
 	write = local_add_return(length, &tail_page->write);
 	tail = write - length;
@@ -993,7 +996,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 		 * it all the way around the buffer, bail, and warn
 		 * about it.
 		 */
-		if (unlikely(next_page == cpu_buffer->commit_page)) {
+		if (unlikely(next_page == commit_page)) {
 			WARN_ON_ONCE(1);
 			goto out_unlock;
 		}