ftrace: reset selftests

The tests may leave stuff in the buffers. This resets the buffers
after each test is run. If a test fails, it does not reset the
buffer to avoid touching a buffer that is corrupted.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/trace/trace.c

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8755a43..6580e7e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -289,6 +289,13 @@
 			printk(KERN_CONT "FAILED!\n");
 			goto out;
 		}
+		/* Only reset on passing, to avoid touching corrupted buffers */
+		for_each_possible_cpu(i) {
+			data = tr->data[i];
+			if (!head_page(data))
+				continue;
+			tracing_reset(data);
+		}
 		printk(KERN_CONT "PASSED\n");
 	}
 #endif