Subject: ixgbe hangs when XDP_TX is enabled

From: "Nikita V. Shirokov" <[email-masked]>
Date: Mon, 20 Aug 2018 12:31:08 -0700

we are getting such errors:

[  408.737313] ixgbe 0000:03:00.0 eth0: Detected Tx Unit Hang (XDP)
                 Tx Queue             <46>
                 TDH, TDT             <0>, <2>
                 next_to_use          <2>
                 next_to_clean        <0>
               tx_buffer_info[next_to_clean]
                 time_stamp           <0>
                 jiffies              <1000197c0>
[  408.804438] ixgbe 0000:03:00.0 eth0: tx hang 1 detected on queue 46, resetting adapter
[  408.804440] ixgbe 0000:03:00.0 eth0: initiating reset due to tx timeout
[  408.817679] ixgbe 0000:03:00.0 eth0: Reset adapter
[  408.866091] ixgbe 0000:03:00.0 eth0: TXDCTL.ENABLE for one or more queues not cleared within the polling period
[  409.345289] ixgbe 0000:03:00.0 eth0: detected SFP+: 3
[  409.497232] ixgbe 0000:03:00.0 eth0: NIC Link is Up 10 Gbps, Flow Control: RX/TX

while running XDP prog on ixgbe nic.
right now i'm seing this on bpfnext kernel 
(latest commit from Wed Aug 15 15:04:25 2018 -0700 ;
9a76aba02a37718242d7cdc294f0a3901928aa57)

looks like this is the same issue as reported by Brenden in
https://www.spinics.net/lists/netdev/msg439438.html