It's glad to see the issue can not repro with the 5.0.0-1007.7 kernel. @sfeole: The line "[ 84.247704]hyperv_fb: unable to send packet via vmbus" usually means the VM has panicked. Do you happen to still keep the full serial log containing this line of error? It would be good to understand this error for the 4.18.0-1013-azure kernel.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-azure in Ubuntu. https://bugs.launchpad.net/bugs/1822133 Title: Azure Instance never recovered during series of instance reboots. Status in linux-azure package in Ubuntu: In Progress Bug description: Description: During SRU Testing of various Azure Instances, there will be some cases where the instance will not respond following a system reboot. SRU Testing only restarts a giving instance once, after it preps all of the necessary files to-be-tested. Series: Disco Instance Size: Basic_A3 Region: (Default) US-WEST-2 Kernel Version: 4.18.0-1013-azure #13-Ubuntu SMP Thu Feb 28 22:54:16 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux I initiated a series of tests which rebooted Azure Cloud instances 50 times. During the 49th Reboot, an Instance failed to return from a reboot.. Upon grabbing the console output the following was seen scrolling endlessly. I have seen this failure in cases where the instance only restarted a handful of times >5 [ 84.247704]hyperv_fb: unable to send packet via vmbus [ 84.247704]hyperv_fb: unable to send packet via vmbus [ 84.247704]hyperv_fb: unable to send packet via vmbus [ 84.247704]hyperv_fb: unable to send packet via vmbus [ 84.247704]hyperv_fb: unable to send packet via vmbus [ 84.247704]hyperv_fb: unable to send packet via vmbus [ 84.247704]hyperv_fb: unable to send packet via vmbus [ 84.247704]hyperv_fb: unable to send packet via vmbus In another test attempt I saw the following failure: ERROR ExtHandler /proc/net/route contains no routes ERROR ExtHandler /proc/net/route contains no routes ERROR ExtHandler /proc/net/route contains no routes ERROR ExtHandler /proc/net/route contains no routes ERROR ExtHandler /proc/net/route contains no routes ERROR ExtHandler /proc/net/route contains no routes ERROR ExtHandler /proc/net/route contains no routes Both of these failures broke networking, Both of these failures were seen at least twice to three times, thus may explain why in some cases we never recover from an instance reboot. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/1822133/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp

