This is tracking the upstream effort needed to deliver the solution to the bug described below.

 Problem Description: Clearly explain the issue.

This issue is opened based on code review and a discussion with Ilya.

The cutlen field of a dp-packet (used for truncating packets for openflows action like output(, max_len=)) is ignored when it comes to TSO packets in the userspace datapath.

The issue is probably also present in the kernel datapath (from my limited understanding of this code).
 

 Impact Assessment: Describe the severity and impact (e.g., network down,availability of a workaround, etc.).

Once TSO'd by SW or HW, output packets will not be of the expected size and recipients may error on receiving such packets.

 Software Versions: Specify the exact versions in use (e.g.,openvswitch3.1-3.1.0-147.el8fdp).

All versions of OVS for which TSO is enabled in the datapath are affected.

  Issue Type: Indicate whether this is a new issue or a regression (if a regression, state the last known working version).

This is not a regression, the issue exists since the support of TSO packets.

 Reproducibility: Confirm if the issue can be reproduced consistently. If not, describe how often it occurs.

Enter a openflow rule asking for truncating packets, then send a TSO packet.

Note: there may be a workaround of announcing that truncate is not available in the userspace datapath if userspace tso is enabled (see check_support() in ofproto-dpif.c). As for the kernel datapath, this must be evaluated.