Microsoft Hyper-V SLES12 Virtual Machines encounter "eth0: unable to send receive completion pkt" error messages

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Environment

SUSE Linux Enterprise Server 12 SP2

SUSE Linux Enterprise Server 12 SP1

SUSE Linux Enterprise Server 12

Situation

The following error messages are seen in the message log intermittently:

2016-11-03T13:39:15.136188-05:00 server1 kernel: [166116.761481] hv_netvsc vmbus_13 eth0: unable to send receive completion pkt (tid 1b65)...retrying 1
2016-11-03T13:39:15.136399-05:00 server1 kernel: [166116.761587] hv_netvsc vmbus_13 eth0: unable to send receive completion pkt (tid 1b65)...retrying 2
2016-11-03T13:39:15.136402-05:00 server1 kernel: [166116.761868] hv_netvsc vmbus_13 eth0: unable to send receive completion pkt (tid 1b65)...retrying 3
2016-11-03T13:39:15.136404-05:00 server1 kernel: [166116.761974] hv_netvsc vmbus_13 eth0: unable to send receive completion pkt (tid 1b65)...retrying 4
2016-11-03T13:39:15.136405-05:00 server1 kernel: [166116.761977] hv_netvsc vmbus_13 eth0: unable to send receive completion pkt (tid 1b65)...give up retrying

Resolution

This network issue is fixed in SLES12 SP2 kernel version 4.4.49-92.11.1.

Cause

This issue is caused by a bug at the Microsoft Hyper-V VM layer under heavy network load.

Additional Information

SLES12 SP2 kernel version 4.4.49-92.11.1
- hv_netvsc: Implement batching of receive completions.

Disclaimer

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