[PATCH 8/8] selftests/ftrace: Add dynamic events argument limitation test case

Masami Hiramatsu (Google)
2025-02-26T06:19:46Z

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Add argument limitation test case for dynamic events.
This is a boudary check for the maximum number of the probe
event arguments.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
.../ftrace/test.d/dynevent/dynevent_limitations.tc | 42 ++++++++++++++++++++
1 file changed, 42 insertions(+)
create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/dynevent_limitations.tc

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/dynevent_limitations.tc b/tools/testing/selftests/ftrace/test.d/dynevent/dynevent_limitations.tc
new file mode 100644
index 000000000000..6b94b678741a
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/dynevent_limitations.tc
@@ -0,0 +1,42 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Checking dynamic events limitations
+# requires: dynamic_events "imm-value":README
+
+# Max arguments limitation
+MAX_ARGS=128
+EXCEED_ARGS=$((MAX_ARGS + 1))
+
+check_max_args() { # event_header
+ TEST_STRING=$1
+ # Acceptable
+ for i in `seq 1 $MAX_ARGS`; do
+ TEST_STRING="$TEST_STRING \\$i"
+ done
+ echo "$TEST_STRING" >> dynamic_events
+ echo > dynamic_events
+ # Error
+ TEST_STRING="$TEST_STRING \\$EXCEED_ARGS"
+ ! echo "$TEST_STRING" >> dynamic_events
+ return 0
+}
+
+# Kprobe max args limitation
+if grep -q "kprobe_events" README; then
+ check_max_args "p vfs_read"
+fi
+
+# Fprobe max args limitation
+if grep -q "f[:[<group>/][<event>]] <func-name>[%return] [<args>]" README; then
+ check_max_args "f vfs_read"
+fi
+
+# Tprobe max args limitation
+if grep -q "t[:[<group>/][<event>]] <tracepoint> [<args>]" README; then
+ check_max_args "t kfree"
+fi
+
+# Uprobe max args limitation
+if grep -q "uprobe_events" README; then
+ check_max_args "p /bin/sh:10"
+fi