Re: [PATCH 3/3] selftests: forwarding: fix pedit tests failure with br_netfilter enabled

On Tue, 10 Feb 2026 18:51:29 +0000 Aleksei Oladko wrote:

The tests use the tc pedit action to modify the IPv4 source address
("pedit ex munge ip src set"), but the IP header checksum is not
recalculated after the modification. As a result, the modified packet
fails sanity checks in br_netfilter after bridging and is dropped,
which causes the test to fail.

Fix this by adding an explicit checksum recalculation using the
"csum ip" action, so the modified packet contains a valid IPv4
checksum.

Note on IPv6:
  The tests in pedit_ip.sh also cover IPv6 (test_ip6_src, test_ip6_dst).
  The csum ip action is harmless for IPv6 packets since IPv6 has no
  header checksum — it will be a no-op.

I think this makes the test fail for us:

make: Entering directory '/srv/vmksft/testing/wt-3/tools/testing/selftests'
make[1]: Nothing to be done for 'all'.
TAP version 13
1..1
# timeout set to 10800
# selftests: net/forwarding: pedit_ip.sh
# 6.13 [+6.13] TEST: ping                                                          [ OK ]
# 7.09 [+0.97] TEST: ping6                                                         [ OK ]
# 7.12 [+0.02] Error: Failed to load TC action module.
# 7.12 [+0.00] We have an error talking to the kernel
# 8.36 [+1.24] TEST: dev veth1 ingress pedit ip src set 198.51.100.1               [FAIL]
# 8.36 [+0.01] Expected to get 10 packets, but got 0.
# 8.37 [+0.01] Error: Cannot find specified filter chain.
# 8.38 [+0.00] We have an error talking to the kernel
# 8.39 [+0.01] Error: Failed to load TC action module.
# 8.39 [+0.00] We have an error talking to the kernel
# 9.63 [+1.24] TEST: dev veth2 egress pedit ip src set 198.51.100.1                [FAIL]
# 9.63 [+0.01] Expected to get 10 packets, but got 0.
# 9.64 [+0.00] Error: Cannot find specified filter chain.
# 9.64 [+0.00] We have an error talking to the kernel
# 9.65 [+0.01] Error: Failed to load TC action module.
# 9.65 [+0.00] We have an error talking to the kernel
# 10.89 [+1.24] TEST: dev veth1 ingress pedit ip dst set 198.51.100.1               [FAIL]
# 10.89 [+0.00] Expected to get 10 packets, but got 0.
# 10.90 [+0.01] Error: Cannot find specified filter chain.
# 10.91 [+0.00] We have an error talking to the kernel
# 10.91 [+0.01] Error: Failed to load TC action module.
# 10.91 [+0.00] We have an error talking to the kernel
# 12.14 [+1.23] TEST: dev veth2 egress pedit ip dst set 198.51.100.1                [FAIL]
# 12.15 [+0.01] Expected to get 10 packets, but got 0.
# 12.15 [+0.00] Error: Cannot find specified filter chain.
# 12.16 [+0.00] We have an error talking to the kernel
# 12.17 [+0.01] Error: Failed to load TC action module.
# 12.17 [+0.00] We have an error talking to the kernel
# 13.42 [+1.24] TEST: dev veth1 ingress pedit ip6 src set 2001:db8:2::1             [FAIL]
# 13.42 [+0.00] Expected to get 10 packets, but got 0.
# 13.43 [+0.01] Error: Cannot find specified filter chain.
# 13.43 [+0.00] We have an error talking to the kernel
# 13.45 [+0.01] Error: Failed to load TC action module.
# 13.45 [+0.00] We have an error talking to the kernel
# 14.69 [+1.24] TEST: dev veth2 egress pedit ip6 src set 2001:db8:2::1              [FAIL]
# 14.69 [+0.00] Expected to get 10 packets, but got 0.
# 14.70 [+0.00] Error: Cannot find specified filter chain.
# 14.70 [+0.00] We have an error talking to the kernel
# 14.71 [+0.01] Error: Failed to load TC action module.
# 14.72 [+0.00] We have an error talking to the kernel
# 15.96 [+1.24] TEST: dev veth1 ingress pedit ip6 dst set 2001:db8:2::1             [FAIL]
# 15.96 [+0.00] Expected to get 10 packets, but got 0.
# 15.97 [+0.01] Error: Cannot find specified filter chain.
# 15.97 [+0.00] We have an error talking to the kernel
# 15.99 [+0.01] Error: Failed to load TC action module.
# 15.99 [+0.00] We have an error talking to the kernel
# 17.23 [+1.24] TEST: dev veth2 egress pedit ip6 dst set 2001:db8:2::1              [FAIL]
# 17.23 [+0.01] Expected to get 10 packets, but got 0.
# 17.24 [+0.00] Error: Cannot find specified filter chain.
# 17.24 [+0.00] We have an error talking to the kernel
not ok 1 selftests: net/forwarding: pedit_ip.sh # exit=1


https://netdev-ctrl.bots.linux.dev/logs/vmksft/forwarding/results/512621/80-pedit-ip-sh/stdout

I could be wrong, kernel.org is having a DNS outage so our CI is a bit
unstable.
-- 
pw-bot: cr