selftests/ftrace: More initialize features in initialize_ftrace

Clear pid filter, synthetic_events, snapshots,
ftrace filter, and trace log in initialize_ftrace(),
since those are used in test cases.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

tools/testing/selftests/ftrace/test.d/functions

@@ -89,12 +89,17 @@ initialize_ftrace() { # Reset ftrace to initial-state
     reset_tracer
     reset_trigger
     reset_events_filter
+    reset_ftrace_filter
     disable_events
     echo > set_event_pid	# event tracer is always on
+    echo > set_ftrace_pid
     [ -f set_ftrace_filter ] && echo | tee set_ftrace_*
     [ -f set_graph_function ] && echo | tee set_graph_*
     [ -f stack_trace_filter ] && echo > stack_trace_filter
     [ -f kprobe_events ] && echo > kprobe_events
     [ -f uprobe_events ] && echo > uprobe_events
+    [ -f synthetic_events ] && echo > synthetic_events
+    [ -f snapshot ] && echo 0 > snapshot
+    clear_trace
     enable_tracing
 }