[PATCH v3 3/4] selftests/ftrace: Add kernel cmdline tracing testcases

From: Masami Hiramatsu (Google) <[email protected]>

Add test cases for kernel command-line tracing options. It verifies
various parameters like trace_buf_size and trace_options by reading
the output of tracing files in sysfs.

Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
---
Changes in v3:
 - Add '# APPLETS: awk' header to cmdline-03-trace-buf-size.sh to request
   awk applet in initramfs.
Changes in v2:
 - Fix buffer_size_kb parsing in cmdline-03-trace-buf-size.sh to handle
   unexpanded buffer string output '1 (expanded: 2048)'.
 - Use grep -qw in cmdline-04-trace-options.sh to match word options
   and avoid matching disabled 'no<option>' entries.
---
 .../boottime/cmdlines/cmdline-01-ftrace.cmdline    |    1 +
 .../cmdlines/cmdline-02-trace-event.cmdline        |    1 +
 .../cmdlines/cmdline-03-trace-buf-size.cmdline     |    1 +
 .../cmdlines/cmdline-04-trace-options.cmdline      |    1 +
 .../cmdlines/cmdline-05-trace-clock.cmdline        |    1 +
 .../cmdlines/cmdline-06-trace-instance.cmdline     |    1 +
 .../ftrace/boottime/tests/cmdline-01-ftrace.sh     |   19 +++++++++++++
 .../boottime/tests/cmdline-02-trace-event.sh       |   26 ++++++++++++++++++
 .../boottime/tests/cmdline-03-trace-buf-size.sh    |   29 ++++++++++++++++++++
 .../boottime/tests/cmdline-04-trace-options.sh     |   23 ++++++++++++++++
 .../boottime/tests/cmdline-05-trace-clock.sh       |   19 +++++++++++++
 .../boottime/tests/cmdline-06-trace-instance.sh    |   24 +++++++++++++++++
 12 files changed, 146 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-01-ftrace.cmdline
 create mode 100644 tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-02-trace-event.cmdline
 create mode 100644 tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-03-trace-buf-size.cmdline
 create mode 100644 tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-04-trace-options.cmdline
 create mode 100644 tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-05-trace-clock.cmdline
 create mode 100644 tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-06-trace-instance.cmdline
 create mode 100644 tools/testing/selftests/ftrace/boottime/tests/cmdline-01-ftrace.sh
 create mode 100644 tools/testing/selftests/ftrace/boottime/tests/cmdline-02-trace-event.sh
 create mode 100644 tools/testing/selftests/ftrace/boottime/tests/cmdline-03-trace-buf-size.sh
 create mode 100644 tools/testing/selftests/ftrace/boottime/tests/cmdline-04-trace-options.sh
 create mode 100644 tools/testing/selftests/ftrace/boottime/tests/cmdline-05-trace-clock.sh
 create mode 100644 tools/testing/selftests/ftrace/boottime/tests/cmdline-06-trace-instance.sh

diff --git a/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-01-ftrace.cmdline b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-01-ftrace.cmdline
new file mode 100644
index 000000000000..4f6fc54240c8
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-01-ftrace.cmdline
@@ -0,0 +1 @@
+ftrace=function
diff --git a/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-02-trace-event.cmdline b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-02-trace-event.cmdline
new file mode 100644
index 000000000000..66bcd29b14cb
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-02-trace-event.cmdline
@@ -0,0 +1 @@
+trace_event=sched:sched_switch,kmem:kmalloc
diff --git a/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-03-trace-buf-size.cmdline b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-03-trace-buf-size.cmdline
new file mode 100644
index 000000000000..e5d1c4a8ca89
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-03-trace-buf-size.cmdline
@@ -0,0 +1 @@
+trace_buf_size=2048K
diff --git a/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-04-trace-options.cmdline b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-04-trace-options.cmdline
new file mode 100644
index 000000000000..51d82f8e948d
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-04-trace-options.cmdline
@@ -0,0 +1 @@
+trace_options=sym-addr,verbose
diff --git a/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-05-trace-clock.cmdline b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-05-trace-clock.cmdline
new file mode 100644
index 000000000000..f72a4ac808a3
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-05-trace-clock.cmdline
@@ -0,0 +1 @@
+trace_clock=global
diff --git a/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-06-trace-instance.cmdline b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-06-trace-instance.cmdline
new file mode 100644
index 000000000000..9618e3e2b88b
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/cmdlines/cmdline-06-trace-instance.cmdline
@@ -0,0 +1 @@
+trace_instance=bar,sched:sched_switch
diff --git a/tools/testing/selftests/ftrace/boottime/tests/cmdline-01-ftrace.sh b/tools/testing/selftests/ftrace/boottime/tests/cmdline-01-ftrace.sh
new file mode 100644
index 000000000000..23a0b15f2dd3
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/tests/cmdline-01-ftrace.sh
@@ -0,0 +1,19 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2026, Google LLC.
+# Check ftrace= kernel command-line tracer setting
+TRACEDIR="/sys/kernel/tracing"
+
+if [ ! -f "$TRACEDIR/current_tracer" ]; then
+	echo "FAIL: current_tracer does not exist"
+	exit 1
+fi
+
+read -r TRACER _ < "$TRACEDIR/current_tracer"
+if [ "$TRACER" != "function" ]; then
+	echo "FAIL: current_tracer is '$TRACER', expected 'function'"
+	exit 1
+fi
+
+echo "PASS: cmdline-01-ftrace"
+exit 0
diff --git a/tools/testing/selftests/ftrace/boottime/tests/cmdline-02-trace-event.sh b/tools/testing/selftests/ftrace/boottime/tests/cmdline-02-trace-event.sh
new file mode 100644
index 000000000000..b793907c48cd
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/tests/cmdline-02-trace-event.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2026, Google LLC.
+# Check trace_event= kernel command-line setting
+TRACEDIR="/sys/kernel/tracing"
+
+if [ ! -d "$TRACEDIR/events/sched/sched_switch" ]; then
+	echo "FAIL: event sched:sched_switch does not exist"
+	exit 1
+fi
+
+if [ ! -d "$TRACEDIR/events/kmem/kmalloc" ]; then
+	echo "FAIL: event kmem:kmalloc does not exist"
+	exit 1
+fi
+
+ENABLE1=$(cat "$TRACEDIR/events/sched/sched_switch/enable")
+ENABLE2=$(cat "$TRACEDIR/events/kmem/kmalloc/enable")
+
+if [ "$ENABLE1" != "1" ] || [ "$ENABLE2" != "1" ]; then
+	echo "FAIL: events not enabled (sched_switch=$ENABLE1, kmalloc=$ENABLE2)"
+	exit 1
+fi
+
+echo "PASS: cmdline-02-trace-event"
+exit 0
diff --git a/tools/testing/selftests/ftrace/boottime/tests/cmdline-03-trace-buf-size.sh b/tools/testing/selftests/ftrace/boottime/tests/cmdline-03-trace-buf-size.sh
new file mode 100644
index 000000000000..4b936f84d4d7
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/tests/cmdline-03-trace-buf-size.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2026, Google LLC.
+# APPLETS: awk
+# Check trace_buf_size= kernel command-line setting
+TRACEDIR="/sys/kernel/tracing"
+
+if [ ! -f "$TRACEDIR/buffer_size_kb" ]; then
+	echo "FAIL: buffer_size_kb does not exist"
+	exit 1
+fi
+
+BUF_RAW=$(cat "$TRACEDIR/buffer_size_kb")
+case "$BUF_RAW" in
+	*"expanded:"*)
+		BUFSIZE=$(echo "$BUF_RAW" | sed -n 's/.*expanded: *\([0-9]*\).*/\1/p')
+		;;
+	*)
+		BUFSIZE=$(echo "$BUF_RAW" | awk '{print $1}')
+		;;
+esac
+
+if [ -z "$BUFSIZE" ] || [ "$BUFSIZE" -lt 2048 ]; then
+	echo "FAIL: buffer_size_kb is '$BUF_RAW', expected >= 2048"
+	exit 1
+fi
+
+echo "PASS: cmdline-03-trace-buf-size"
+exit 0
diff --git a/tools/testing/selftests/ftrace/boottime/tests/cmdline-04-trace-options.sh b/tools/testing/selftests/ftrace/boottime/tests/cmdline-04-trace-options.sh
new file mode 100644
index 000000000000..53a65b55f7a7
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/tests/cmdline-04-trace-options.sh
@@ -0,0 +1,23 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2026, Google LLC.
+# Check trace_options= kernel command-line setting
+TRACEDIR="/sys/kernel/tracing"
+
+if [ ! -f "$TRACEDIR/trace_options" ]; then
+	echo "FAIL: trace_options file does not exist"
+	exit 1
+fi
+
+if ! grep -qw "sym-addr" "$TRACEDIR/trace_options"; then
+	echo "FAIL: sym-addr option is not set in trace_options"
+	exit 1
+fi
+
+if ! grep -qw "verbose" "$TRACEDIR/trace_options"; then
+	echo "FAIL: verbose option is not set in trace_options"
+	exit 1
+fi
+
+echo "PASS: cmdline-04-trace-options"
+exit 0
diff --git a/tools/testing/selftests/ftrace/boottime/tests/cmdline-05-trace-clock.sh b/tools/testing/selftests/ftrace/boottime/tests/cmdline-05-trace-clock.sh
new file mode 100644
index 000000000000..d6de9f6e2090
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/tests/cmdline-05-trace-clock.sh
@@ -0,0 +1,19 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2026, Google LLC.
+# Check trace_clock= kernel command-line setting
+TRACEDIR="/sys/kernel/tracing"
+
+if [ ! -f "$TRACEDIR/trace_clock" ]; then
+	echo "FAIL: trace_clock file does not exist"
+	exit 1
+fi
+
+if ! grep -q '\[global\]' "$TRACEDIR/trace_clock"; then
+	CLOCK=$(cat "$TRACEDIR/trace_clock")
+	echo "FAIL: trace_clock is not set to global ($CLOCK)"
+	exit 1
+fi
+
+echo "PASS: cmdline-05-trace-clock"
+exit 0
diff --git a/tools/testing/selftests/ftrace/boottime/tests/cmdline-06-trace-instance.sh b/tools/testing/selftests/ftrace/boottime/tests/cmdline-06-trace-instance.sh
new file mode 100644
index 000000000000..aae7f0a86d81
--- /dev/null
+++ b/tools/testing/selftests/ftrace/boottime/tests/cmdline-06-trace-instance.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2026, Google LLC.
+# Check trace_instance= kernel command-line setting
+TRACEDIR="/sys/kernel/tracing"
+
+if [ ! -d "$TRACEDIR/instances/bar" ]; then
+	echo "FAIL: trace instance bar does not exist"
+	exit 1
+fi
+
+if [ ! -d "$TRACEDIR/instances/bar/events/sched/sched_switch" ]; then
+	echo "FAIL: event sched_switch does not exist in instance bar"
+	exit 1
+fi
+
+ENABLE=$(cat "$TRACEDIR/instances/bar/events/sched/sched_switch/enable")
+if [ "$ENABLE" != "1" ]; then
+	echo "FAIL: event sched_switch is not enabled in instance bar ($ENABLE)"
+	exit 1
+fi
+
+echo "PASS: cmdline-06-trace-instance"
+exit 0