Re: [PATCH net] selftests: net: fix race condition in icmp.sh causing CKI sporadic failures

On Mon, 12 Oct 2026 18:23:32 +0530 Prasenjit Mukherjee wrote:

CKI reports sporadic failures in icmp.sh, Davide suggests this might be

Please expand local acronyms, no idea what CKI was, I had to google it.

caused by a race condition where tcpdump starts capturing after the last of
expected ICMP unreachable packets have been sent.
Fix this replacing tcpdump with a tc flower filter that
matches ICMP Destination Unreachable (type 3, code 0),
and match on act_gact counters instead.
This will remove any race condition to appear.

Would really be great if you could say something like "with this patch
applied I run the test in $my-ci and no failures happened"

Fixes: 7e9838b7915e2 ("selftests/net: Add icmp.sh for testing ICMP dummy address responses")
CC: Toke Høiland-Jørgensen <redacted>
Suggested-by: Davide Caratti <redacted>
Reviewed-by: Davide Caratti <redacted>
Reported-by: CKI Project <redacted>
Closes: https://datawarehouse.cki-project.org/issue/3658

Silly number of tags