Same. RHEL/CentOS went without a hitch. The age of the kernel start’s to concern me, though.
According to the top comment in one of the posts in HN even 4.9 and 4.4 use a less ideal patch: https://news.ycombinator.com/item?id=16085672
I can’t really judge how much RH engineers are capable of fixing that kind of stuff in a kernel that’s officially out of support upstream.
Based on the general quality of RHEL/RHV I trust them to do the right thing, but I have no insight whatsoever in how kernel development actually works.
Red Hat pays the salary of a couple kernel developers, backporting security fixes is a pretty big part of their job. Keep in mind, RHEL/CentOS 7 doesn't even use something newer like 4.4 - it's still on 3.10 because Red Hat guarantees a stable kABI throughout the lifetime of a release
This seems like one of those things that is very hard to get right: https://forums.aws.amazon.com/thread.jspa?messageID=823033
I'm guessing Xen PV isn't well tested by Red Hat anymore since most (if not all) of their paying customers still (stuck) using it are likely on RHEL5, which they haven't released a patch for yet due to that very reason.
I'm kind of shocked Amazon doesn't have something like Linode's Fennix, but you can always do an EBS snapshot of your /boot volume and revert it if a kernel upgrade breaks stuff.
Of course, I also go into any updates with a rollback plan. ITIL sucks, but one thing it taught me was the value of well documented plans any time you make changes to production systems.