xen crashes on system resume

Bug #1788499 reported by Mathieu Tarral
10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
xen (Ubuntu)
New
Undecided
Unassigned

Bug Description

When I suspend my laptop while running under Xen, I cannot resume the session later on.

If I open my laptop again i will just see a black screen, and then my BIOS vendor a couple of seconds later, indicating that Xen crashed.

This is 100% reproducible.

I'm ready to give you more information if you tell me where to look for.

informations:
kernel: 4.15.0-32-generic

lsb_release
Description: Ubuntu 18.04 LTS
Release: 18.04

apt-cache policy xen-hypervisor-4.9-amd64
xen-hypervisor-4.9-amd64:
  Installed: 4.9.2-0ubuntu1
  Candidate: 4.9.2-0ubuntu1
  Version table:
 *** 4.9.2-0ubuntu1 500
        500 http://fi.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status

Tags: bot-comment
description: updated
Revision history for this message
Ubuntu Foundations Team Bug Bot (crichton) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1788499/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

tags: added: bot-comment
affects: ubuntu → xen (Ubuntu)
Revision history for this message
Andreas Hasenack (ahasenack) wrote :

@smb, do you have any idea about this?

Revision history for this message
Stefan Bader (smb) wrote :

@Andreas, well the 4.15.0-32 kernel was the security update to handle Foreshadow/L1TF. To mitigate that CPU bug there had been substantial changes to how non-present pages are represented in the page tables. For suspend/resume many parts have to play together. With Xen, there is the hypervisor which is a kernel on its own (and I would guess it also hooks into some BIOS functions visible to guests). The hypervisor loads and runs the kernel for the dom0 guest. This is the linux kernel and dom0 is a paravirtualized guest with special privileges.

So bottom line, its really hard to figure out what goes wrong. Especially without any visual clue. I assume there is a triple fault or the like (which causes the reboot) when trying to bring the virtual CPUs of dom0 back. So the screen is still blanked and I do not think any of the peripheral devices have been re-activated, yet.

One step to verify that it is indeed the change from 4.15.0-31 to 4.15.0-32 would be to select the older kernel at boot via grub. If -31 works but -32 not then research can likely be concentrated on upstream hypervisor changes which mention acessing page table entries of guests.

Revision history for this message
Joshua Powers (powersj) wrote :

I am going to mark this incomplete and ask the reporter to please try the older kernel as described in comment 3. Once you try that please respond back here and move the bug back to "New".

Changed in xen (Ubuntu):
status: New → Incomplete
Revision history for this message
Mathieu Tarral (mathieu-tarral) wrote :

Hi,

Thanks for your reply.
i can already say that i had this since a coup'e of mo ths, and it didn't appeared with the latest kernels 4.0.15-31 or 32.

I tested it with older kernels (-22 IIRC) and it was also crashing.

I will have my hands on my laptop by monday.

is there a way i can get a log of what's happening in Xen ?

Changed in xen (Ubuntu):
status: Incomplete → New
Revision history for this message
Mathieu Tarral (mathieu-tarral) wrote :

4.15.0-30-generic #32-Ubuntu SMP

My oldest kernels have been deleted, all i have is:

- 4.15.0-32-generic, resume bug present
- 4.15.0-30-generic, resume bug present
- 4.13.0-41-generic, doesn't boot with Xen for some reason

I hope that helps.

To post a comment you must log in.
This report contains Public information  
Everyone can see this information.

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.