On 5/26/20 3:23 PM, Saeed Mahameed wrote:
>
> looks like: xdp->data_meta has some invalid value.
> and i think its boundaries should be checked on
> bpf_xdp_adjust_head() regardless of the issue that you are seeing.
>
> Anyway I can't figure out the reason for this without extra digging
> since in mlx5 we do xdp_set_data_meta_invalid(); before passing the xdp
> buff to the bpf program, so it is not clear why would you hit the
> memove in bpf_xdp_adjust_head().
>
>> [ 7270.033014] bpf_xdp_adjust_head+0x68/0x80
>> [ 7270.037126] bpf_prog_7d719f00afcf8e6c_xdp_l2fwd_prog+0x198/0xa10
>> [ 7270.043284] mlx5e_xdp_handle+0x55/0x500 [mlx5_core]
>> [ 7270.048277] mlx5e_skb_from_cqe_linear+0xf0/0x1b0 [mlx5_core]
>> [ 7270.054053] mlx5e_handle_rx_cqe+0x64/0x140 [mlx5_core]
>> [ 7270.059297] mlx5e_poll_rx_cq+0x8c8/0xa30 [mlx5_core]
>> [ 7270.064373] mlx5e_napi_poll+0xdc/0x6a0 [mlx5_core]
>> [ 7270.069260] net_rx_action+0x13d/0x3d0
>> [ 7270.073020] __do_softirq+0xdd/0x2d0
>>
>>
>> git bisect chased it to
>> 13209a8f7304 ("Merge
>> git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")
>>
>
> Are you testing vanilla kernel ?
yes - git bisect had no changes on top.
>
> what does the xdp program do with the frame/xdp_buff other than
> bpf_xdp_adjust_head()/ i mean which other bpf helper is it calling ?
>
nothing relevant. map lookup of a <mac,vlan> pair, map lookup of next
index, pop the vlan header, redirect to tap device:
https://github.com/dsahern/bpf-progs/blob/master/ksrc/xdp_l2fwd.c
A program that I have been using for 5-6 months.
