[PATCH 6/6 v2] tracing/histogram: Add simple tests for stacktrace usage of synthetic events

[Steven Rostedt <rostedt@goodmis.org>]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

Update the selftests to include a test of passing a stacktrace between the
events of a synthetic event.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace.c                          |  2 +-
 .../trigger-synthetic-event-stack.tc          | 24 +++++++++++++++++++
 .../trigger-synthetic-event-syntax.tc         |  6 +++++
 3 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-stack.tc

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d445789dc247..beb7b0e77874 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5803,7 +5803,7 @@ static const char readme_msg[] =
 #ifdef CONFIG_SYNTH_EVENTS
 	"  events/synthetic_events\t- Create/append/remove/show synthetic events\n"
 	"\t  Write into this file to define/undefine new synthetic events.\n"
-	"\t     example: echo 'myevent u64 lat; char name[]' >> synthetic_events\n"
+	"\t     example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n"
 #endif
 #endif
 ;
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-stack.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-stack.tc
new file mode 100644
index 000000000000..755dbe94ccf4
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-stack.tc
@@ -0,0 +1,24 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test inter-event histogram trigger trace action with dynamic string param
+# requires: set_event synthetic_events events/sched/sched_process_exec/hist "long[]' >> synthetic_events":README
+
+fail() { #msg
+    echo $1
+    exit_fail
+}
+
+echo "Test create synthetic event with stack"
+
+
+echo 's:wake_lat pid_t pid; u64 delta; unsigned long[] stack;' > dynamic_events
+echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace  if prev_state == 1||prev_state == 2' >> events/sched/sched_switch/trigger
+echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,s=$st:onmax($delta).trace(wake_lat,prev_pid,$delta,$s)' >> events/sched/sched_switch/trigger
+echo 1 > events/synthetic/wake_lat/enable
+sleep 1
+
+if ! grep -q "=>.*sched" trace; then
+    fail "Failed to create synthetic event with stack"
+fi
+
+exit 0
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-syntax.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-syntax.tc
index 2968cdc7df30..366f1f3ad906 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-syntax.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-syntax.tc
@@ -70,6 +70,12 @@ grep "myevent[[:space:]]unsigned long var" synthetic_events
 echo "myevent char var[10]" > synthetic_events
 grep "myevent[[:space:]]char\[10\] var" synthetic_events
 
+if grep -q 'long\[\]' README; then
+  # test stacktrace type
+  echo "myevent unsigned long[] var" > synthetic_events
+  grep "myevent[[:space:]]unsigned long\[\] var" synthetic_events
+fi
+
 do_reset
 
 exit 0
-- 
2.39.0