SEGFAULT on upgrade to 0.102-0ubuntu1~20.04.1

[Carl Hörberg]

Today a bunch of our ubuntu 20.04 servers on AWS EC2 (both amd64 and arm) upgraded to netplan 0.102-0ubuntu1~20.04.1, which resulted in a segfault when netplan ran generate, and then took the whole network down with it, the servers had to be force rebooted.

kernel: [1938106.074273] netplan[2874371]: segfault at 100000000 ip 00007f72cb991675 sp 00007ffe8be03158 error 4 in libc-2.31.so[7f72cb82b000+178000]
kernel: [1938106.074282] Code: 00 00 0f 1f 00 31 c0 c5 f8 77 c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 89 f9 48 89 fa c5 f9 ef c0 83 e1 3f 83 f9 20 77 2b <c5> fd 74 0f c5 fd d7 c1 85 c0 0f 85 eb 00 00 00 48 83 c7 20 83 e1
systemd[2874368]: /usr/lib/systemd/system-generators/netplan terminated by signal SEGV.

/etc/netplan/ is the default from aws ubuntu 20.04 image.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: netplan.io 0.102-0ubuntu1~20.04.1
ProcVersionSignature: Ubuntu 5.4.0-1041.43-aws 5.4.94
Uname: Linux 5.4.0-1041-aws x86_64
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
CasperMD5CheckResult: skip
Date: Wed Apr 7 15:34:08 2021
Ec2AMI: ami-09dd2e08d601bff67
Ec2AMIManifest: (unknown)
Ec2AvailabilityZone: us-west-2a
Ec2InstanceType: t3.micro
Ec2Kernel: unavailable
Ec2Ramdisk: unavailable
ProcEnviron:
 TERM=screen-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
 SHELL=/bin/bash
SourcePackage: netplan.io
UpgradeStatus: No upgrade log present (probably fresh install)