[PATCH] fix oprofile vfree warning on error

On error we can call __free_cpu_buffers with only some buffers allocated.
I was getting a bunch of vfree warnings when I hit it, we should check
before calling vfree.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/oprofile/cpu_buffer.c

@@ -36,8 +36,10 @@ static void __free_cpu_buffers(int num)
 {
 	int i;
  
-	for_each_online_cpu(i)
+	for_each_online_cpu(i) {
+		if (cpu_buffer[i].buffer)
 			vfree(cpu_buffer[i].buffer);
+	}
 }