[J][SRU][PATCH 1/1] selftests/ftrace: Stop tracing while reading the trace file by default

[Po-Hsu Lin]

From: Masami Hiramatsu <mhiramat at kernel.org>

BugLink: https://bugs.launchpad.net/bugs/2029405

Stop tracing while reading the trace file by default, to prevent
the test results while checking it and to avoid taking a long time
to check the result.
If there is any testcase which wants to test the tracing while reading
the trace file, please override this setting inside the test case.

This also recovers the pause-on-trace when clean it up.

Link: https://lkml.kernel.org/r/163529053143.690749.15365238954175942026.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat at kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt at goodmis.org>
(cherry picked from commit 25b95138728028dd0f576d9f252bc8f0b6c609fa)
Signed-off-by: Po-Hsu Lin <po-hsu.lin at canonical.com>
---
 tools/testing/selftests/ftrace/ftracetest       |  2 +-
 tools/testing/selftests/ftrace/test.d/functions | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/ftrace/ftracetest b/tools/testing/selftests/ftrace/ftracetest
index 8ec1922..c3311c8 100755
--- a/tools/testing/selftests/ftrace/ftracetest
+++ b/tools/testing/selftests/ftrace/ftracetest
@@ -428,7 +428,7 @@ for t in $TEST_CASES; do
     exit 1
   fi
 done
-(cd $TRACING_DIR; initialize_ftrace) # for cleanup
+(cd $TRACING_DIR; finish_ftrace) # for cleanup
 
 prlog ""
 prlog "# of passed: " `echo $PASSED_CASES | wc -w`
diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
index 000fd05..5f6cbec 100644
--- a/tools/testing/selftests/ftrace/test.d/functions
+++ b/tools/testing/selftests/ftrace/test.d/functions
@@ -124,10 +124,22 @@ initialize_ftrace() { # Reset ftrace to initial-state
     [ -f uprobe_events ] && echo > uprobe_events
     [ -f synthetic_events ] && echo > synthetic_events
     [ -f snapshot ] && echo 0 > snapshot
+
+# Stop tracing while reading the trace file by default, to prevent
+# the test results while checking it and to avoid taking a long time
+# to check the result.
+    [ -f options/pause-on-trace ] && echo 1 > options/pause-on-trace
+
     clear_trace
     enable_tracing
 }
 
+finish_ftrace() {
+    initialize_ftrace
+# And recover it to default.
+    [ -f options/pause-on-trace ] && echo 0 > options/pause-on-trace
+}
+
 check_requires() { # Check required files and tracers
     for i in "$@" ; do
         r=${i%:README}
-- 
2.7.4