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

James Clark
2024-06-20T11:31:39Z

On 20/06/2024 11:36, Oleg Nesterov wrote:
> Again, I can't really comment, I know almost nothing about perf, but
>
> On 06/20, Tiezhu Yang wrote:
>>
>> On 06/20/2024 05:08 PM, Oleg Nesterov wrote:
>>>
>>> But to me the very idea of arm64-specific and "kernel only" member in
>>> perf_event_attr looks a bit strange.
>>
>> I noticed that there is a similar arm64-specific change in
>> commit 09519ec3b19e ("perf: Add perf_event_attr::config3")
>
> but this is another thing even if I have no idea what .config3 means.
>
> If nothing else, what do you think, say, tools/perf can do with ->bp_priv?

Yeah, including the tools side change in the same series might help to
explain. It's not obvious what the end goal is from the commit message.

Thanks
James

>
> What should sys_perf_event_open() do if bp_priv != 0 comes from user space?
>
> Nevermind, please forget, I leave this to you and maintainers.
>
> Oleg.
>
>