sefltests/tracing: Add a test for tracepoint events on modules

Add a test case for tracepoint events on modules. This checks if it can add
and remove the events correctly.

Link: https://lore.kernel.org/all/172397781494.286558.7581515061075998225.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <[email protected]>

tools/testing/selftests/ftrace/config

@@ -20,6 +20,7 @@ CONFIG_PREEMPT_TRACER=y
 CONFIG_PROBE_EVENTS_BTF_ARGS=y
 CONFIG_SAMPLES=y
 CONFIG_SAMPLE_FTRACE_DIRECT=m
+CONFIG_SAMPLE_TRACE_EVENTS=m
 CONFIG_SAMPLE_TRACE_PRINTK=m
 CONFIG_SCHED_TRACER=y
 CONFIG_STACK_TRACER=y

tools/testing/selftests/ftrace/test.d/dynevent/add_remove_tprobe_module.tc

@@ -0,0 +1,61 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - add/remove tracepoint probe events on module
+# requires: dynamic_events "t[:[<group>/][<event>]] <tracepoint> [<args>]":README
+
+rmmod trace-events-sample ||:
+if ! modprobe trace-events-sample ; then
+  echo "No trace-events sample module - please make CONFIG_SAMPLE_TRACE_EVENTS=m"
+  exit_unresolved;
+fi
+trap "rmmod trace-events-sample" EXIT
+
+echo 0 > events/enable
+echo > dynamic_events
+
+TRACEPOINT1=foo_bar
+TRACEPOINT2=foo_bar_with_cond
+
+echo "t:myevent1 $TRACEPOINT1" >> dynamic_events
+echo "t:myevent2 $TRACEPOINT2" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+test -d events/tracepoints/myevent1
+test -d events/tracepoints/myevent2
+
+echo "-:myevent2" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+! grep -q myevent2 dynamic_events
+
+echo > dynamic_events
+
+clear_trace
+
+:;: "Try to put a probe on a tracepoint in non-loaded module" ;:
+rmmod trace-events-sample
+
+echo "t:myevent1 $TRACEPOINT1" >> dynamic_events
+echo "t:myevent2 $TRACEPOINT2" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+test -d events/tracepoints/myevent1
+test -d events/tracepoints/myevent2
+
+echo 1 > events/tracepoints/enable
+
+modprobe trace-events-sample
+
+sleep 2
+
+grep -q "myevent1" trace
+grep -q "myevent2" trace
+
+rmmod trace-events-sample
+trap "" EXIT
+
+echo 0 > events/tracepoints/enable
+echo > dynamic_events
+clear_trace