Re: [PATCH v9 7/8] selftests/ftrace: Add a testcase for fprobe events on module

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Sat, 18 Apr 2026 01:18:39 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Add a testcase for fprobe events on module, which unloads a kernel
> module on which fprobe events are probing and ensure the ftrace
> hash map is cleared correctly.
> 
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
>  Changes in v9:
>  - Use "trace-events-sample" instead of "trace_events_sample"
>  - Add checking unload module and remove core-kernel event case.
>  - Check test module exists when unloading it in EXIT.
>  Changes in v8:
>  - Newly added.
> ---
>  .../test.d/dynevent/add_remove_fprobe_module.tc    |   87 ++++++++++++++++++++
>  1 file changed, 87 insertions(+)
>  create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe_module.tc
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe_module.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe_module.tc
> new file mode 100644
> index 000000000000..c358c5071f15
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe_module.tc
> @@ -0,0 +1,87 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: Generic dynamic event - add/remove fprobe events on module
> +# requires: dynamic_events "f[:[<group>/][<event>]] <func-name>[%return] [<args>]":README enabled_functions
> +
> +rmmod trace-events-sample ||:
> +if ! modprobe trace-events-sample ; then
> +  echo "No trace-events sample module - please make CONFIG_SAMPLE_TRACE_EVENTS=m"
> +  exit_unresolved;
> +fi
> +trap "lsmod | grep -q trace-event-sample && rmmod trace-events-sample" EXIT

Oops, we need to check "trace_events_sample".

Thanks,

> +
> +echo 0 > events/enable
> +echo > dynamic_events
> +
> +FUNC1='foo_bar*'
> +FUNC2='vfs_read'
> +
> +:;: "Add an event on the test module" ;:
> +echo "f:test1 $FUNC1" >> dynamic_events
> +echo 1 > events/fprobes/test1/enable
> +
> +:;: "Ensure it is enabled" ;:
> +funcs=`cat enabled_functions | wc -l`
> +test $funcs -ne 0
> +
> +:;: "Check the enabled_functions is cleared on unloading" ;:
> +rmmod trace-events-sample
> +funcs=`cat enabled_functions | wc -l`
> +test $funcs -eq 0
> +
> +:;: "Check it is kept clean" ;:
> +modprobe trace-events-sample
> +echo 1 > events/fprobes/test1/enable || echo "OK"
> +funcs=`cat enabled_functions | wc -l`
> +test $funcs -eq 0
> +
> +:;: "Add another event not on the test module" ;:
> +echo "f:test2 $FUNC2" >> dynamic_events
> +echo 1 > events/fprobes/test2/enable
> +
> +:;: "Ensure it is enabled" ;:
> +ofuncs=`cat enabled_functions | wc -l`
> +test $ofuncs -ne 0
> +
> +:;: "Disable and remove the first event"
> +echo 0 > events/fprobes/test1/enable
> +echo "-:fprobes/test1" >> dynamic_events
> +funcs=`cat enabled_functions | wc -l`
> +test $ofuncs -eq $funcs
> +
> +:;: "Disable and remove other events" ;:
> +echo 0 > events/fprobes/enable
> +echo > dynamic_events
> +funcs=`cat enabled_functions | wc -l`
> +test $funcs -eq 0
> +
> +rmmod trace-events-sample
> +
> +:;: "Add events on kernel and test module" ;:
> +modprobe trace-events-sample
> +echo "f:test1 $FUNC1" >> dynamic_events
> +echo 1 > events/fprobes/test1/enable
> +echo "f:test2 $FUNC2" >> dynamic_events
> +echo 1 > events/fprobes/test2/enable
> +ofuncs=`cat enabled_functions | wc -l`
> +test $ofuncs -ne 0
> +
> +:;: "Unload module (ftrace entry should be removed)" ;:
> +rmmod trace-events-sample
> +funcs=`cat enabled_functions | wc -l`
> +test $funcs -ne 0
> +test $ofuncs -ne $funcs
> +
> +:;: "Disable and remove core-kernel fprobe event" ;:
> +echo 0 > events/fprobes/test2/enable
> +echo "-:fprobes/test2" >> dynamic_events
> +
> +:;: "Ensure ftrace is disabled." ;:
> +funcs=`cat enabled_functions | wc -l`
> +test $funcs -eq 0
> +
> +echo 0 > events/fprobes/enable
> +echo > dynamic_events
> +
> +trap "" EXIT
> +clear_trace
> 


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