Re: [bpf-next PATCH 3/3] bpf: add sample program to trace map events

Jesper Dangaard Brouer
2018-04-23T20:22:43Z

On Mon, 23 Apr 2018 14:08:02 -0600
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:

> On Mon, Apr 23, 2018 at 04:08:36PM +0200, Sebastiano Miano wrote:
> >
> > That's in fact the real use case for the first two patches. Since bpf
> > tracepoints are still a rather common (and easy to use) troubleshooting and
> > monitoring tool why shouldn't we "enhance" their support with the newly
> > added map/prog IDs?
>
> because these tracepoints can be abused in the way that this patch demonstrated.
> Whether to keep this patch in the series or not is irrelevant.

I don't understand your abuse use-case, can you explain what you mean?

You do realize that these tracepoints can _only_ monitor the userspace
map activity (not kernel map changes) ... and we _do_ need a way to
debug this (and without the map_id I can tell which map).

--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer