Bug 2004083 - Incorrectly negotiated feature causes OpenvSwitch upcalls to fail
Summary: Incorrectly negotiated feature causes OpenvSwitch upcalls to fail
Status: POST
Alias: None
Product: Red Hat Enterprise Linux Fast Datapath
Classification: Red Hat
Component: openvswitch2.16
Version: FDP 20.G
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
: ---
Assignee: Open vSwitch development team
QA Contact: ovs-qe
Depends On:
TreeView+ depends on / blocked
Reported: 2021-09-14 13:36 UTC by Mark Gray
Modified: 2021-11-14 22:29 UTC (History)
3 users (show)

Fixed In Version:
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System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker FD-1536 0 None None None 2021-09-14 13:38:13 UTC

Description Mark Gray 2021-09-14 13:36:24 UTC
Description of problem:
OVS user space component does not correctly negotiate kernel space features on RHEL 7 causing user space to incorrectly detect 'per-cpu-dispatch' mode. This causes upcalls to user space to fail as user space believes it is in 'per-cpu-dispatch' mode whereas kernel space is not.

Version-Release number of selected component (if applicable):
Kernel: 3.10.0-1160.el7.x86_64
OVS: latest master (https://github.com/openvswitch/ovs/commit/00d3d4a7d3750ab1d907d58894ad817febce1cf7)

How reproducible:

Steps to Reproduce:
1. /usr/local/share/openvswitch/scripts/ovs-ctl start
2. ovs-vsctl add-br br0
3. ovs-appctl dpif-netlink/dispatch-mode

Actual results:
ovs-system: per-cpu dispatch mode

Expected results:
ovs-system: per-vport dispatch mode

Additional info:

Comment 1 Mark Gray 2021-09-14 13:41:03 UTC
After investigation, the root-cause appears to be that the RHEL7 openvswitch kernel module does not check for unsupported features.

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