Comment 0 for bug 2016269

[Impact]

after the last merge of the v5.15 stable (see https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2003134) has introduced a bug on netlink netfilter conntrack messages.

The problematic commit is 95fcb42e5f20 ("netfilter: ctnetlink: fix compilation warning after data race fixes in ct mark"):
https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy/commit/?id=95fcb42e5f20

This bug has been fixed in upstream commit 9f7dd42f0db1 ("netfilter: ctnetlink: revert to dumping mark regardless of event type"):
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9f7dd42f0db1

which has been backported in v5.15.103:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bef8cf77e21c

[Test Case]

Run 'conntrack -E' and check the output.

Before the problematic commit:
> tcp 6 2 ESTABLISHED src=10.100.0.1 dst=10.200.0.1 sport=6789 dport=12345 src=10.200.0.1 dst=10.100.0.1 sport=12345 dport=6789 [ASSURED] mark=0 use=1

'mark=' is seen on connrtack event

after:
> tcp 6 2 ESTABLISHED src=10.100.0.1 dst=10.200.0.1 sport=6789 dport=12345 src=10.200.0.1 dst=10.100.0.1 sport=12345 dport=6789 [ASSURED] use=1

=> 'mark=' is not seen.

[Regression Potential]

The patch is quite simple. It has been backported in the official 5.15 stable. The risk of regression should be contained.