Re: [PATCH v6 3/5] samples: ftrace: Save required argument registers in sample trampolines

Steven Rostedt
2023-04-05T20:42:30Z

On Wed, 5 Apr 2023 20:02:48 +0200
Florent Revest <revest@chromium.org> wrote:

> The ftrace-direct-too sample traces the handle_mm_fault function whose
> signature changed since the introduction of the sample. Since:
> commit bce617edecad ("mm: do page fault accounting in handle_mm_fault")
> handle_mm_fault now has 4 arguments. Therefore, the sample trampoline
> should save 4 argument registers.
>
> s390 saves all argument registers already so it does not need a change
> but x86_64 needs an extra push and pop.
>
> This also evolves the signature of the tracing function to make it
> mirror the signature of the traced function.
>

Should probably add:

Cc: stable@vger.kernel.org
Fixes: bce617edecad ("mm: do page fault accounting in handle_mm_fault")

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve