Comment 2 for bug 1771276

There is no crash. All needed information is on https://wiki.strongswan.org/issues/2571 #6
The reason is explained https://wiki.strongswan.org/issues/2571 #17, so the issue is already resolved in 4.16, but since 4.15 is EOL and 4.14 did non have this issue and Ubuntu 18.04 is a LTS release you might consider applying https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=87cdf3148b11