[PATCH v9 09/10] selftests: ftrace: Add wprobe trigger testcase
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: 2026-07-17 14:21:22
Also in:
linux-doc, linux-perf-users, lkml
Subsystem:
kernel selftest framework, the rest, tracing · Maintainers:
Shuah Khan, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Add a testcase for checking wprobe trigger. This sets set_wprobe and
clear_wprobe triggers on fprobe events to watch dentry access.
So this depends on both wprobe and fprobe.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v9:
- Drop dentry cache after removing tempfile for on-disk
filesystem.
Changes in v8:
- Use TMPDIR for making a test file.
- Ensure the fprobe and target functions exists, if not, exit
with UNRESOLVED (== skip).
Changes in v7:
- Add a newline at the end of file.(style fix)
- Use dentry_kill instead of __dentry_kill.
Changes in v5:
- Enable CONFIG_WPROBE_TRIGGERS in the config for ftrace test.
Changes in v3:
- Newly added.
---
tools/testing/selftests/ftrace/config | 1
.../ftrace/test.d/trigger/trigger-wprobe.tc | 70 ++++++++++++++++++++
2 files changed, 71 insertions(+)
create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-wprobe.tc
diff --git a/tools/testing/selftests/ftrace/config b/tools/testing/selftests/ftrace/config
index d2f503722020..ecdee77f360f 100644
--- a/tools/testing/selftests/ftrace/config
+++ b/tools/testing/selftests/ftrace/config@@ -28,3 +28,4 @@ CONFIG_TRACER_SNAPSHOT=y CONFIG_UPROBES=y CONFIG_UPROBE_EVENTS=y CONFIG_WPROBE_EVENTS=y +CONFIG_WPROBE_TRIGGERS=y
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-wprobe.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-wprobe.tc
new file mode 100644
index 000000000000..0634259e2c65
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-wprobe.tc@@ -0,0 +1,70 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: event trigger - test wprobe trigger +# requires: dynamic_events "w[:[<group>/][<event>]] [r|w|rw]@<addr>[:<len>]":README events/sched/sched_process_fork/trigger + +echo 0 > tracing_on +rm -f $TMPDIR/hoge + +:;: "Add a wprobe event used by trigger" ;: +echo 'w:watch rw@0:8 address=$addr value=+0($addr)' > dynamic_events + +# we will skip this test if fprobe is not supported. +if ! grep -Fq "f[:[<group>/][<event>]] <func-name>[%return] [<args>]" README; then + echo "UNRESOLVED: fprobe is not supported" + exit_unresolved +fi + +# we will skip this test if the target function does not exist. +if ! grep -wq "do_truncate" /proc/kallsyms; then + echo "UNRESOLVED: do_truncate not found" + exit_unresolved +fi +if ! grep -wq "dentry_kill" /proc/kallsyms; then + echo "UNRESOLVED: dentry_kill not found" + exit_unresolved +fi + +:;: "Add events for triggering wprobe" ;: +echo 'f:truncate do_truncate dentry=$arg2' >> dynamic_events +echo 'f:dentry_kill dentry_kill dentry=$arg1' >> dynamic_events + +:;: "Add wprobe triggers" ;: +echo 'set_wprobe:watch:dentry' >> events/fprobes/truncate/trigger +echo 'clear_wprobe:watch:dentry' >> events/fprobes/dentry_kill/trigger +cat events/fprobes/truncate/trigger | grep ^set_wprobe +cat events/fprobes/dentry_kill/trigger | grep ^clear_wprobe + +:;: "Ensure wprobe is still disabled" ;: +cat events/wprobes/watch/enable | grep 0 + +:;: "Enable events for triggers" ;: +echo 1 >> events/fprobes/truncate/enable +echo 1 >> events/fprobes/dentry_kill/enable + +:;: "Start test workload" ;: +echo 1 >> tracing_on + +echo aaa > $TMPDIR/hoge +echo bbb > $TMPDIR/hoge +echo ccc > $TMPDIR/hoge +rm $TMPDIR/hoge + +:;: "Drop dentry caches (for dentry_kill)" ;: +# Use append (>>) to avoid calling do_truncate again. +sync && echo 2 >> /proc/sys/vm/drop_caches + +:;: "Check trace results" ;: +cat trace | grep watch + + +:;: "Ensure wprobe becomes disabled again" ;: +cat events/wprobes/watch/enable | grep 0 + +:;: "Remove wprobe triggers" ;: +echo '!set_wprobe:watch:dentry' >> events/fprobes/truncate/trigger +echo '!clear_wprobe:watch' >> events/fprobes/dentry_kill/trigger +! grep ^set_wprobe events/fprobes/truncate/trigger +! grep ^clear_wprobe events/fprobes/dentry_kill/trigger + +exit 0