Hi, We still experience this bug. We use Hyper-V 2012 and use Veeam to create VM backups (though this fact might be irrelevant). We upgraded our Ubuntu 14.04 to the latest xenial kernel (4.4.0-91) and still experience the VM hanging/freezing/stacktracing regularly directly after backup. Sometimes the server becomes unresponsive and shows the following error in the syslog: "Hyper-V VSS: VSS: freeze of /boot: Operation not supported" (after that it dies). The stacktrace included now did not crash the server, but it was definitely caused by the VM backup.
Some more info: uname -a: Linux SERVERNAME 4.4.0-91-generic #114~14.04.1-Ubuntu SMP Wed Aug 9 08:47:26 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux lsmod | grep 'hv_' : hv_utils 28672 2 hv_storvsc 20480 260 ptp 20480 1 hv_utils scsi_transport_fc 65536 1 hv_storvsc hv_netvsc 40960 0 hv_vmbus 90112 6 hyperv_keyboard,hv_netvsc,hid_hyperv,hv_utils,hyperv_fb,hv_storvsc dpkg --list | grep '4.4': ii linux-cloud-tools-4.4.0-91-generic 4.4.0-91.114~14.04.1 amd64 Linux kernel version specific cloud tools for version 4.4.0-91 ii linux-cloud-tools-virtual-lts-xenial 4.4.0.91.75 amd64 This package will always depend on the latest minimal generic kernel cloud tools. ii linux-generic-lts-xenial 4.4.0.91.75 amd64 Complete Generic Linux kernel and headers ii linux-headers-4.4.0-91 4.4.0-91.114~14.04.1 all Header files related to Linux kernel version 4.4.0 ii linux-headers-4.4.0-91-generic 4.4.0-91.114~14.04.1 amd64 Linux kernel headers for version 4.4.0 on 64 bit x86 SMP ii linux-headers-generic-lts-xenial 4.4.0.91.75 amd64 Generic Linux kernel headers ii linux-image-4.4.0-91-generic 4.4.0-91.114~14.04.1 amd64 Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii linux-image-extra-4.4.0-91-generic 4.4.0-91.114~14.04.1 amd64 Linux kernel extra modules for version 4.4.0 on 64 bit x86 SMP ii linux-image-generic-lts-xenial 4.4.0.91.75 amd64 Generic Linux kernel image ii linux-lts-xenial-cloud-tools-4.4.0-91 4.4.0-91.114~14.04.1 amd64 Linux kernel version specific cloud tools for version 4.4.0-91 ii linux-lts-xenial-tools-4.4.0-91 4.4.0-91.114~14.04.1 amd64 Linux kernel version specific tools for version 4.4.0-91 ii linux-tools-4.4.0-91-generic 4.4.0-91.114~14.04.1 amd64 Linux kernel version specific tools for version 4.4.0-91 ii linux-tools-virtual-lts-xenial 4.4.0.91.75 amd64 This package will always depend on the latest minimal generic kernel tools. I hope this issue can get fixed soon. Stop making backups is not really an option for us. ** Attachment added: "hyperv_backup_kernel_freeze_stacktrace.txt" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1679898/+attachment/4933584/+files/hyperv_backup_kernel_freeze_stacktrace.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1679898 Title: [Hyper-V] Ubuntu VM crash during Hyper-V backup or live migration after installing kernel 4.4.0-72 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1679898/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs