Re: [PATCH bpf-next] bpf: fix memory leak in bpf_lwt_xmit_reroute

On 2/28/19 10:57 AM, Peter Oskolkov wrote:

David: I'm not sure how to test GSO (I assume we are talking about GSO
here) in
the selftest: the encapping code sets SKB_GSO_DODGY flag, and veth does
not support
dodginess: "tx-gso-robust: off [fixed]".

If the "dodgy" flag is not set, then gso validation in dev.c passes, and
large GSO packets
happily go through; if the "dodgy" flag is set, "dodgy" GSO packets are
rejected, TCP does
segmentation, and non-GSO packets happily go through (with an mtu tweak
to the LWT tunnel).

So I see three options:
- add a sysctl to _not_ set SKB_GSO_DODGY flag in lwt_bpf.c =>
handle_gso_type();
- change veth to accept "dodgy" GSO packets
- test the code "as is", meaning that GSO will be tried and disabled by
TCP stack

Which approach would you prefer?

definitely not a sysctl.

After that, I don't have a suggestion for GSO at the moment.