[PATCH v6 4/4] selftests/ftrace: Add accept cases for fprobe list syntax

Seokwoo Chung (Ryan)
2026-02-05T13:59:07Z

Add fprobe_list.tc to test the comma-separated symbol list syntax
with :entry/:exit suffixes. Three scenarios are covered:

1. List with default (entry) behavior and ! exclusion
2. List with explicit :entry suffix
3. List with :exit suffix for return probes

Each test verifies that the correct functions appear in
enabled_functions and that excluded (!) symbols are absent.

Note: The existing tests add_remove_fprobe.tc, fprobe_syntax_errors.tc,
and add_remove_fprobe_repeat.tc check their "requires" line against the
tracefs README for the old "%return" syntax pattern. Since the README
now documents ":entry|:exit" instead, these tests report UNSUPPORTED.
Their "requires" lines need updating in a follow-up patch.

Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
---
.../ftrace/test.d/dynevent/fprobe_list.tc | 92 +++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc
new file mode 100644
index 000000000000..45e57c6f487d
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc
@@ -0,0 +1,92 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Fprobe event list syntax and :entry/:exit suffixes
+# requires: dynamic_events "f[:[<group>/][<event>]] <func-name>[:entry|:exit] [<args>]":README
+
+# Setup symbols to test. These are common kernel functions.
+PLACE=vfs_read
+PLACE2=vfs_write
+PLACE3=vfs_open
+
+echo 0 > events/enable
+echo > dynamic_events
+
+# Get baseline count of enabled functions (should be 0 if clean, but be safe)
+if [ -f enabled_functions ]; then
+ ocnt=`cat enabled_functions | wc -l`
+else
+ ocnt=0
+fi
+
+# Test 1: List default (entry) with exclusion
+# Target: Trace vfs_read and vfs_open, but EXCLUDE vfs_write
+echo "f:test/list_entry $PLACE,!$PLACE2,$PLACE3" >> dynamic_events
+grep -q "test/list_entry" dynamic_events
+test -d events/test/list_entry
+
+echo 1 > events/test/list_entry/enable
+
+grep -q "$PLACE" enabled_functions
+grep -q "$PLACE3" enabled_functions
+! grep -q "$PLACE2" enabled_functions
+
+# Check count (Baseline + 2 new functions)
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -ne $((ocnt + 2)) ]; then
+ exit_fail
+fi
+
+# Cleanup Test 1
+echo 0 > events/test/list_entry/enable
+echo "-:test/list_entry" >> dynamic_events
+! grep -q "test/list_entry" dynamic_events
+
+# Count should return to baseline
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -ne $ocnt ]; then
+ exit_fail
+fi
+
+# Test 2: List with explicit :entry suffix
+# (Should behave exactly like Test 1)
+echo "f:test/list_entry_exp $PLACE,!$PLACE2,$PLACE3:entry" >> dynamic_events
+grep -q "test/list_entry_exp" dynamic_events
+test -d events/test/list_entry_exp
+
+echo 1 > events/test/list_entry_exp/enable
+
+grep -q "$PLACE" enabled_functions
+grep -q "$PLACE3" enabled_functions
+! grep -q "$PLACE2" enabled_functions
+
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -ne $((ocnt + 2)) ]; then
+ exit_fail
+fi
+
+# Cleanup Test 2
+echo 0 > events/test/list_entry_exp/enable
+echo "-:test/list_entry_exp" >> dynamic_events
+
+# Test 3: List with :exit suffix
+echo "f:test/list_exit $PLACE,!$PLACE2,$PLACE3:exit" >> dynamic_events
+grep -q "test/list_exit" dynamic_events
+test -d events/test/list_exit
+
+echo 1 > events/test/list_exit/enable
+
+# Even for return probes, enabled_functions lists the attached symbols
+grep -q "$PLACE" enabled_functions
+grep -q "$PLACE3" enabled_functions
+! grep -q "$PLACE2" enabled_functions
+
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -ne $((ocnt + 2)) ]; then
+ exit_fail
+fi
+
+# Cleanup Test 3
+echo 0 > events/test/list_exit/enable
+echo "-:test/list_exit" >> dynamic_events
+
+clear_trace
--
2.43.0