Re: [PATCH 4/6] hw_breakpoint: Factor out __modify_user_hw_breakpoint function

[Milind Chabbi]

On Mon, Nov 27, 2017 at 2:01 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Mon, Nov 27, 2017 at 01:50:30PM -0800, Milind Chabbi wrote:
>> The possible checks is infinite
>
> struct perf_event_attr is very much a finite data type.
>
> Something as simple as:
>
>         struct perf_event_attr tmp1 = new_attr, tmp2 = event->attr;
>
>         tmp1.bp_type = tmp2.bp_type;
>         tmp1.bp_addr = tmp2.bp_addr;
>         tmp1.bp_len  = tmp2.bp_len;
>
>         if (memcmp(&tmp1, &tmp2, sizeof(tmp1)))
>                 return -EINVAL;
>
> would actually do the checks __modify_user_hw_breakpoint() needs to do.

Ok. That seems like a slick idea. I will post a patch that does this.