Re: Xenomai 4 / oob_sendmsg crashes kernel from tidbits/oob-net-icmp

[Philippe Gerum <rpm@xenomai.org>]

Sri Subramanian <sridhar.subramanian@gmail.com> writes:

> On Wed, Jul 20, 2022 at 10:47 AM Philippe Gerum <rpm@xenomai.org> wrote:
>>
>>
>> Ok. On my end, I'll connect a pi4 with the i.MX6, to add the GENET MAC
>> module to the picture.
>>
>
> It looks like the GENET MAC driver (or the interface) is the culprit.
> For some reason, it
> restricts the packets sent to 10 after every netif down/up toggle.
>

Weird. I'll trace that.

> I attached a network adapter card to the PCIe interface and connected
> that to the switch.
>
> Both the oob-net-icmp and my packet generator are able to call oob_sendmsg
> continuously!
>
> One anomaly I found in my experimentation:
>
> - When I try the USB-ethernet adapter, the packets are not seen by the
> EVL mini-stack and
> despite the fact that /sys/class/net/eth1.42/oob_port is set to 1 and
> control/net_vlans is 42,
> the packets are read/responded to by the Linux kernel and oob-net-icmp
> is just waiting.
>
> Previously I've used the USB-ethernet adapter for all tcp/ip
> communication to the device
> and it works just fine.
>

I suspect something is wrong in the oob traffic detection handler,
namely [1]. For some reason, incoming packets are not seen as belonging
to the oob vlan. Most likely something I overlooked when looking for the
802.1q encapsulation, which the USB adapter triggers.

[1] https://source.denx.de/Xenomai/xenomai4/linux-evl/-/blob/v5.15.y-evl-rebase/kernel/evl/net/ethernet/input.c#L36

-- 
Philippe.