[PATCH 3.18 25/56] selftests/ftrace: Add snapshot and tracing_on test case

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

[ Upstream commit 82f4f3e69c5c29bce940dd87a2c0f16c51d48d17 ]

Add a testcase for checking snapshot and tracing_on
relationship. This ensures that the snapshotting doesn't
affect current tracing on/off settings.

Link: http://lkml.kernel.org/r/153149932412.11274.15289227592627901488.stgit@devbox

Cc: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Cc: Hiraku Toyooka <hiraku.toyooka@xxxxxxxxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 tools/testing/selftests/ftrace/test.d/00basic/snapshot.tc |   28 ++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/00basic/snapshot.tc

--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/00basic/snapshot.tc
@@ -0,0 +1,28 @@
+#!/bin/sh
+# description: Snapshot and tracing setting
+# flags: instance
+
+[ ! -f snapshot ] && exit_unsupported
+
+echo "Set tracing off"
+echo 0 > tracing_on
+
+echo "Allocate and take a snapshot"
+echo 1 > snapshot
+
+# Since trace buffer is empty, snapshot is also empty, but allocated
+grep -q "Snapshot is allocated" snapshot
+
+echo "Ensure keep tracing off"
+test `cat tracing_on` -eq 0
+
+echo "Set tracing on"
+echo 1 > tracing_on
+
+echo "Take a snapshot again"
+echo 1 > snapshot
+
+echo "Ensure keep tracing on"
+test `cat tracing_on` -eq 1
+
+exit 0