Fresh Eoan upgrade fails to boot dom0 with message "decoding failed" (kernel 5.3.0)
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
xen (Ubuntu) |
Fix Released
|
High
|
Stefan Bader | ||
Disco |
Fix Released
|
High
|
Unassigned | ||
Eoan |
Fix Released
|
High
|
Unassigned |
Bug Description
[SRU Justification]
IMPORTANT NOTE: See comment #14 (must upload to Disco and copy forward to newer releases with binaries)
[Impact]
Due to a kernel change, it is impossible to bring up a Eoan or later kernel as dom0 (the hypervisor starts and then fails with a "decode failed" message.
[Fix]
Pick 3 patches from upstream Xen which handle fixes to the lz4 compression.
[Testcase]
Start a Xen host with a Eoan kernel. This either succeeds or fails.
[Risk of Regression]
Low, all 3 patches are for a specific decompression method which is used early on boot. This either works or does not and is 100% fatal right now.
---
A freshly upgraded amd64 system with Ubuntu 19.10 and Xen 4.9 won't boot dom0. It fails with the attached screen (saying "Decoding failed ********** Panic on CPU 0: Could not set up DOM0 Guest OS").
The system booted fine before the upgrade from 19.04. Dom0 still boots if kernel 5.0.0.32 (from Ubuntu 19.04) is selected in grub.
Release: Ubuntu 19.10
kernel: 5.3.0-19-generic (also verified with 5.3.0-21-generic from eoan-proposed)
xen-system-amd64 version: 4.9.2-0ubuntu2
xen-utils-4.9 version: 4.9.2-0ubuntu2
Changed in xen (Ubuntu Disco): | |
importance: | Undecided → High |
Changed in xen (Ubuntu Eoan): | |
importance: | Undecided → High |
Changed in xen (Ubuntu): | |
importance: | Undecided → High |
Changed in xen (Ubuntu Disco): | |
status: | New → Fix Committed |
Changed in xen (Ubuntu Disco): | |
status: | Fix Committed → In Progress |
Changed in xen (Ubuntu Eoan): | |
status: | Confirmed → In Progress |
description: | updated |
tags: |
added: verification-done verification-done-disco verification-done-eoan removed: verification-needed verification-needed-disco |
Changed in xen (Ubuntu Eoan): | |
status: | In Progress → Fix Committed |
I should add two comments:
- I can boot in non-xen ubuntu with the same kernel that doesn't work as dom0.
- Since I found reports of "decoding failed" issues due to the change to lz4 compression in 19.10, I tried changing back to gzip compression in /etc/initramfs- tools/initramfs .conf (and running update-initramfs -u), and this didn't help.