Hi, f15ca723c1 ("net: don't call update_pmtu unconditionally") fixes NULL derefs caused by a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path"), which was backported to 4.14.24. We've received reports of panics with Open vSwitch and Weave through 4.14.30 (https://github.com/coreos/bugs/issues/2382) and at least the latter is resolved by backporting the patch.
Thanks, --Benjamin Gilbert