Xen guest time handling is broken after a migration

[Doug Goldstein]

[Impact]
Xen guest time is not stable after a migration.

[Test Case]
Create a Xen guest and migrate it. Check dmesg.

[ 187.249951] Freezing user space processes ... (elapsed 0.001 seconds) done.
[ 187.251137] OOM killer disabled.
[ 187.251137] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[ 187.252299] suspending xenstore...
[ 187.266987] xen:grant_table: Grant tables using version 1 layout
[18446743811.706476] OOM killer enabled.
[18446743811.706478] Restarting tasks ... done.
[18446743811.720505] Setting capacity to 16777216

[Fix]
The following upstream commit fixes the issue:

"xen: Fix x86 sched_clock() interface for xen"
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=867cefb4cb1012f42cada1c7d1f35ac8dd276071

This issue is for xenial as the fix has been back ported to bionic.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1845035

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Po-Hsu Lin (cypressyew)]

This patch could be found in:
 * Eoan
 * Disco
 * Bionic

Change the nomination accordingly.