Re: [PATCH] arm64: hw_breakpoint: Save privilege of access control via ptrace

Will Deacon
2024-06-20T09:30:13Z

On Thu, Jun 20, 2024 at 11:08:07AM +0200, Oleg Nesterov wrote:
> On 06/20, Tiezhu Yang wrote:
> >
> > On 06/19/2024 11:15 PM, Oleg Nesterov wrote:
> > >>--- a/include/uapi/linux/perf_event.h
> > >>+++ b/include/uapi/linux/perf_event.h
> > >>@@ -467,6 +467,7 @@ struct perf_event_attr {
> > >> __u32 wakeup_watermark; /* bytes before wakeup */
> > >> };
> > >>
> > >>+ __u8 bp_priv;
> > >> __u32 bp_type;
> > >
> > >Is it safe to add the new member in the middle of uapi struct?
> > >This will break userspace...
> >
> > Let me put the new member "bp_priv" at the end of uapi struct
> > perf_event_attr in the next version if you are OK with it.
>
> And add PERF_ATTR_SIZE_VER9 ?
>
> Well, you can safely ignore me, you should ask the maintainers ;)
>
> But to me the very idea of arm64-specific and "kernel only" member in
> perf_event_attr looks a bit strange.

Yeah, completely agreed.

Will