Re: [PATCH] selftests/ftrace: Account for fprobe attachment at creation

Masami Hiramatsu
2026-04-09T08:29:58Z

On Thu, 09 Apr 2026 13:18:19 +0800
Cao Ruichuang <create0818@163.com> wrote:

> Hi Masami,
>
> I reran this in a clean QEMU boot environment with only the minimal
> tracefs setup and the add_remove_fprobe sequence.
>
> I saw the same behavior there: after creating myevent1/2/3,
> enabled_functions went from 2 to 4 before any event was enabled, and
> enabling myevent1/2/3 did not increase the count further. After cleanup,
> it returned to the original baseline again.

Hmm, that does not mean test failure but could be a bug.
Can you dump the enabled_functions and share it when the
test failed?

> So this does not look like a dirty tracing environment issue. The
> failing testcase assumption appears to be that the attachment happens on
> enable, while on the current kernel it is already visible after create.

What kernel are you using? I need to check why this happens.
I guess there is a change which introduces this issue.

Thank you,

>
> Thanks,
> Cao Ruichuang
>

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