We're also seeing the same symptoms under Xen version: 3.4.2 (preserve- AD) with the following guest kernels.
Linux web1 2.6.32-50-server #112-Ubuntu SMP Tue Jul 9 20:45:08 UTC 2013 x86_64 GNU/Linux Linux web2 2.6.32-67-server #134-Ubuntu SMP Wed Sep 24 18:55:00 UTC 2014 x86_64 GNU/Linux Due to the nature of the issue, we're unable to run apport-collect. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1199987 Title: 2.6.32-49 kernel hangs during reboot under XenServer 6.0 PV guest Status in “linux” package in Ubuntu: Confirmed Bug description: Kernel 2.6.32-49 hangs at reboot (though not halt) when run under a Xen PV guest. Our hypervisor is XenServer 6.0 with all the latest patches. If we revert to 2.6.32-48, the problem goes away and reboots are successful. This suggests a regression introduced in -49, possibly this patch (though I am not certain): * kernel/sys.c: call disable_nonboot_cpus() in kernel_restart() - LP: #1193044 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1199987/+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