Re: [PATCH V3 1/6] perf/core: Adding PMU driver specific configuration

[Peter Zijlstra]

On Fri, Aug 05, 2016 at 09:41:15AM -0600, Mathieu Poirier wrote:
> On 4 August 2016 at 10:59, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > On Thu, Jul 28, 2016 at 03:42:18PM -0600, Mathieu Poirier wrote:
> >> This patch somewhat mimics the work done on address filters to
> >> add the infrastructure needed to pass PMU specific HW
> >> configuration to the driver before a session starts.
> >
> > I'm thinking we want to specify a syntax and validate the string matches
> > the syntax in the generic code.
> 
> The syntax is checked in the lexer making sure that nothing other than
> @cfg or @cfg=config is sent to the kernel.  From there validation is
> done in the PMU driver that implements the set_drv_configs()
> interface.
> 
> I am not sure to get you point here - can I ask you to provide more details?

What keeps random userspace from sending malformed strings in? There's
more userspace than just the perf tool.

The kernel needs to validate structure.