@rbalint, we have not seen the same issue with the 4.15 linux-aws-hwe kernels used in xenial. At this time, the backport to xenial is not necessary.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-aws in Ubuntu. https://bugs.launchpad.net/bugs/1864041 Title: xen_netfront devices unresponsive after hibernation/resume Status in ec2-hibinit-agent package in Ubuntu: Fix Released Status in linux-aws package in Ubuntu: New Status in ec2-hibinit-agent source package in Xenial: Incomplete Status in linux-aws source package in Xenial: New Status in ec2-hibinit-agent source package in Bionic: Fix Released Status in linux-aws source package in Bionic: New Status in ec2-hibinit-agent source package in Eoan: Fix Released Status in linux-aws source package in Eoan: Won't Fix Status in ec2-hibinit-agent source package in Focal: Fix Released Status in linux-aws source package in Focal: New Bug description: [Impact] The xen_netfront device is sometimes unresponsive after a hibernate and resume event. This is limited to the c4, c5, m4, m5, r4, r5 instance families, all of which are xen based, and support hibernation. When the issue occurrs, the instance is inaccessible without a full restart. Debugging by running a process which outputs regularly to the serial console shows that the instance is still running. [Test Case] 1) Launch an c4, c5, m4, m5, r4, r5 instance type with a 5.0 or 5.3 kernel with on-demand hibernation support enabled. 2) Start a long-running process which generates messages to the serial console 3) Begin observing these messages on the console (using the AWS UI or CLI to grab a screenshot). 4) Suspend and resume the instance, continuing to refresh the console screenshot. 5) The screenshot should continue to show updates even if ssh access is no longer working. [Regression Potential] The workaround in ec2-hibinit-agent is reloading the xen_netfront kernel module before restarting systemd-networkd. If the kernel module is removed (for example when hitting LP: #1615381) the module reloading fails and the instance can not restore network connections. This is expected to a be very rare situation and the module reload is the best workaround the Kernel Team found to mitigate the original issue. The workaround also adds a 2 second delay before reloading the modules to let things settle a bit after resuming. The 2 seconds is very short compared to the overall time needed resuming an instance. [Original Bug Text] The xen_netfront device is sometimes unresponsive after a hibernate and resume event. This is limited to the c4, c5, m4, m5, r4, r5 instance families, all of which are xen based, and support hibernation. When the issue occurrs, the instance is inaccessible without a full restart. Debugging by running a process which outputs regularly to the serial console shows that the instance is still running. A workaround is to build the xen_netfront module separately and restart the module and networking during the resume handler. For example: modprobe -r xen_netfront modprobe xen_netfront systemctl restart systemd-networkd With this workaround in place, the unresponsive issue is no longer observed. To reproduce this problem: 1) Launch an c4, c5, m4, m5, r4, r5 instance type with a 5.0 or 5.3 kernel with on-demand hibernation support enabled. 2) Start a long-running process which generates messages to the serial console 3) Begin observing these messages on the console (using the AWS UI or CLI to grab a screenshot). 4) Suspend and resume the instance, continuing to refresh the console screenshot. 5) The screenshot should continue to show updates even if ssh access is no longer working. --- ProblemType: Bug ApportVersion: 2.20.9-0ubuntu7.9 Architecture: amd64 DistroRelease: Ubuntu 18.04 Ec2AMI: ami-0edf3b95e26a682df Ec2AMIManifest: (unknown) Ec2AvailabilityZone: us-west-2a Ec2InstanceType: m4.large Ec2Kernel: unavailable Ec2Ramdisk: unavailable Package: linux-aws 4.15.0.1058.59 PackageArchitecture: amd64 ProcEnviron: TERM=screen PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=C.UTF-8 SHELL=/bin/bash ProcVersionSignature: User Name 5.0.0-1025.28-aws 5.0.21 Tags: bionic ec2-images Uname: Linux 5.0.0-1025-aws x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm audio cdrom dialout dip floppy lxd netdev plugdev sudo video _MarkForUpload: True To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ec2-hibinit-agent/+bug/1864041/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
