On Tue, Nov 27, 2018 at 5:25 PM Eric Dumazet <eric.duma...@gmail.com> wrote: > > > > On 11/27/2018 04:07 PM, Cong Wang wrote: > > On Tue, Nov 27, 2018 at 3:48 PM Eric Dumazet <eric.duma...@gmail.com> wrote: > > >> > >> But the padding might be added on normal packets (say 1000 bytes + 3 bytes > >> of padding) ? > > > > I never see other padding cases than ETH_ZLEN. Does ethernet standard > > require padding for other cases? I only read the section "3.2.8 Pad field" > > in > > the standard. > > > > Padding can be done by senders, eg using AF_PACKET, > added at the tail of a regular IP/IP6 frame of 1000 or 6000 bytes.
I tried the trafgen script you provided, it doesn't trigger any checksum fault. So, it is probably a different case. > > Note that mlx5 will presumably set CHECKSUM_UNNECESSARY for standard > protocols, > so if you want to reproduce the issue, you might need to find an IP frame that > mlx5 is not able to checksum validate. This warning is 100% reproducible with a TCP RST packet (no data) here, after I find the right switch which pads non-zero's. This is also how I verified this patch. Thanks.
