On 10/29/2018 07:27 PM, Cong Wang wrote:
> Hi,
>
> On Mon, Oct 29, 2018 at 5:19 PM Paweł Staszewski <pstaszew...@itcare.pl>
> wrote:
>>
>> Sorry not complete - followed by hw csum:
>>
>> [ 342.190831] vlan1490: hw csum failure
>> [ 342.190835] CPU: 52 PID: 0 Comm: swapper/52 Not tainted 4.19.0+ #1
>> [ 342.190836] Call Trace:
>> [ 342.190839] <IRQ>
>> [ 342.190849] dump_stack+0x46/0x5b
>> [ 342.190856] __skb_checksum_complete+0x9a/0xa0
>> [ 342.190859] tcp_v4_rcv+0xef/0x960
>> [ 342.190864] ip_local_deliver_finish+0x49/0xd0
>> [ 342.190866] ip_local_deliver+0x5e/0xe0
>> [ 342.190869] ? ip_sublist_rcv_finish+0x50/0x50
>> [ 342.190870] ip_rcv+0x41/0xc0
>> [ 342.190874] __netif_receive_skb_one_core+0x4b/0x70
>> [ 342.190877] netif_receive_skb_internal+0x2f/0xd0
>> [ 342.190879] napi_gro_receive+0xb7/0xe0
>> [ 342.190884] mlx5e_handle_rx_cqe+0x7a/0xd0
>> [ 342.190886] mlx5e_poll_rx_cq+0xc6/0x930
>> [ 342.190888] mlx5e_napi_poll+0xab/0xc90
>
>
> We got exactly the same backtrace in our data center. However,
> it is not easy for us to reproduce it, do you have any clue to reproduce it?
>
> If you do, try to tcpdump the packets triggering this warning, it could
> be useful for debugging.
>
> Also, we tried to apply commit d55bef5059dd057bd, the warning _still_
> occurs. We tried to revert the offending commit 88078d98d1bb, it
> disappears. So it is likely that commit 88078d98d1bb introduces
> more troubles than the one fixed by d55bef5059dd057bd.
>
Or this could be that mlx5 driver is buggy when dealing with VLAN tags.
It both uses vlan_tci (hardware vlan offload) in skb _and_ this piece of code
in mlx5e_handle_csum()
if (network_depth > ETH_HLEN)
/* CQE csum is calculated from the IP header and does
* not cover VLAN headers (if present). This will add
* the checksum manually.
*/
skb->csum = csum_partial(skb->data + ETH_HLEN,
network_depth - ETH_HLEN,
skb->csum);
That seems strange to me, because skb_vlan_untag() will not adjust skb->csum in
this case.
