On Fri, Jan 7, 2022 at 1:54 PM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote:
> +
> +#define NUM_PKTS 1000000
It takes 7 seconds on my kvm with kasan and lockdep
and will take much longer in BPF CI.
So it needs to be lower otherwise CI will struggle.
> + /* The XDP program we run with bpf_prog_run() will cycle through all
> + * three xmit (PASS/TX/REDIRECT) return codes starting from above, and
> + * ending up with PASS, so we should end up with two packets on the dst
> + * iface and NUM_PKTS-2 in the TC hook. We match the packets on the UDP
> + * payload.
> + */
could you keep cycling through all return codes?
That should make the test stronger.
> +
> + /* We enable forwarding in the test namespace because that will cause
> + * the packets that go through the kernel stack (with XDP_PASS) to be
> + * forwarded back out the same interface (because of the packet dst
> + * combined with the interface addresses). When this happens, the
> + * regular forwarding path will end up going through the same
> + * veth_xdp_xmit() call as the XDP_REDIRECT code, which can cause a
> + * deadlock if it happens on the same CPU. There's a local_bh_disable()
> + * in the test_run code to prevent this, but an earlier version of the
> + * code didn't have this, so we keep the test behaviour to make sure the
> + * bug doesn't resurface.
> + */
> + SYS("sysctl -qw net.ipv6.conf.all.forwarding=1");
Does it mean that without forwarding=1 the kernel will dead lock ?!
