On Tue, 27 Jan 2026 22:51:29 +0000 Aleksei Oladko wrote:

This series addresses several issues in the networking kselftests
that cause false-positive failures depending on the host environment,
kernel configuration, or library versions.

The main focus of these changes is to isolate tests from the host
environment (using namespaces) and to ensure proper fallback or
skipping when dependencies are missing.

Summary of changes:
1. Adds a check for cls_basic module in fib_tests. Without this
   module, the test fails when attempting to add tc rules instead
   of skipping.
2. Fixes ovs-dpctl.py to return a non-zero exit code when pyroute2
   is too old. This allows pmtu.sh to correctly fall back to ovs-vsctl
   instead of assuming the configuration was successful.
3,4. Move reuseport and pmtu.sh tests info dedicated network namespaces.
   This prevents failures caused by port conflicts with host processes
   or interference from host firewall rules.
5. Ensures io_uring is enabled via sysctl before running io_uring_zerocopy
   test, preventing failures on systems where kernel.io_uring_disabled
   is set.

Something in this series breaks the pmtu test for us in the CI:

# 64.84 [+2.54] TEST: IPv6, bridged geneve6: PMTU exceptions - nexthop objects      [ OK ]
# 65.73 [+0.89]   ovs_bridge not supported
# 65.73 [+0.00] TEST: IPv4, OVS vxlan4: PMTU exceptions                             [SKIP]
# 67.20 [+1.47]   ovs_bridge not supported
# 67.20 [+0.00] TEST: IPv6, OVS vxlan4: PMTU exceptions                             [SKIP]
# 68.66 [+1.45]   ovs_bridge not supported
# 68.66 [+0.00] TEST: IPv4, OVS vxlan6: PMTU exceptions                             [SKIP]
# 70.11 [+1.45]   ovs_bridge not supported
# 70.11 [+0.00] TEST: IPv6, OVS vxlan6: PMTU exceptions                             [SKIP]
# 71.57 [+1.45]   ovs_bridge not supported
# 71.57 [+0.00] TEST: IPv4, OVS geneve4: PMTU exceptions                            [SKIP]
# 73.01 [+1.44]   ovs_bridge not supported
# 73.01 [+0.00] TEST: IPv6, OVS geneve4: PMTU exceptions                            [SKIP]
# 74.46 [+1.45]   ovs_bridge not supported
# 74.46 [+0.00] TEST: IPv4, OVS geneve6: PMTU exceptions                            [SKIP]
# 75.92 [+1.46]   ovs_bridge not supported
# 75.93 [+0.00] TEST: IPv6, OVS geneve6: PMTU exceptions                            [SKIP]

https://netdev-ctrl.bots.linux.dev/logs/vmksft/net/results/492641/137-pmtu-wrapper-sh/stdout

It was fine before:

https://netdev-ctrl.bots.linux.dev/logs/vmksft/net-dbg/results/492461/6-pmtu-sh/stdout

Since this is a bash test there are of course no logs to go by.. :/

I tried running 
 python tools/testing/selftests/net/openvswitch/ovs-dpctl.py add-dp br0
in a netns and that works just fine. 

No idea what's going on..