** Changed in: linux (Ubuntu)
Status: In Progress => Invalid
** Changed in: ubuntu-z-systems
Status: Fix Committed => Fix Released
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https://bugs.launchpad.net/bugs/1994601
Title:
[UBUNTU 18.04] Ubuntu 18.04 kernel 4.15.0-194 crashes on IPL
Status in Ubuntu on IBM z Systems:
Fix Released
Status in linux package in Ubuntu:
Invalid
Status in linux source package in Bionic:
Fix Released
Bug description:
SRU Justification:
==================
[ Impact ]
* Ubuntu 18.04 / bionic installations with latest kernel 4.15.0-194
are no longer able to IPL (boot) on IBM z14 or newer hardware.
* This issue got introduced by upstream commit e4f74400308c
"s390/archrandom: simplify back to earlier design and initialize earlier"
that was SRUed to 18.04/bionic based on LP#1989625,
which made changes in the s390s IPL/boot area of kernel/arch/random.
* The reason seems to be that the bad patch moves the decision about
if arch randomness is available to setup.c function setup_randomness().
This code uses a static_key s390_arch_random_available.
But in the Canonical kernel the initialization function
for the jump labels (where the static keys are based on)
jump_label_init() is called in generic start_kernel()
wheres in the upstream kernel the init function is
called early in setup_arch().
* Reverting this commit from bionic master-next makes bionic systems
again bootable.
(https://launchpad.net/~fheimes/+archive/ubuntu/test/)
[ Test Plan ]
* An IBM z14 or LinuxONE II or newer system is needed.
* Now install latest bionic on that system - doesn't if it's on LPAR,
z/VM or KVM.
* After the installation (an the trigger of the post install reboot),
the system will not come up.
* To test a patched kernel with e4f74400308c can be tested in the
following way:
* Install 18.04 GA and prevent it from doing any kernel updates.
* Means, install in 'island' mode
or select in d-i 'Advanced Installation'
and explicitly choose '4.15.0-50 generic' to install.
* That allows the system to come up and to update the kernel to
a modified one.
* Then reboot and verify if the system comes up properly.
[ Where problems could occur ]
* Problems could occur due to the fact that the commit
was not cleanly reversible because of minor context changes.
* Adjustments that were needed might break other things if not
done carefully.
* Further commits (applied after e4f74400308c) may still rely
on the bad e4f74400308c commit - or even further patches
(from upstream stable).
* In worst case IPL / boot might get broken,
even on hardware older than z14.
* If the revert works fine can be easily tested and was tested based on
https://launchpad.net/~fheimes/+archive/ubuntu/test/
and the above test plan.
[ Other Info ]
* Ubuntu 20.04 (focal, using legacy image with virt-install)
was tested as well, but is not affected by this issue.
__________
---Problem Description---
Ubuntu 18.04 crashes during IPL with no output on the console.
Contact Information = Viktor Mihajlovski <[email protected]>
---uname output---
n/a
Machine Type = 3096
---Debugger---
A debugger is not configured
---Steps to Reproduce---
Install Ubuntu 18.04 as a KVM guest using the following command:
virt-install -n bionic --cdrom
/var/lib/libvirt/images/ubuntu-18.04.5-server-s390x.iso --memory 2048
--disk size=8
then reboot.
Stack trace output:
no
Oops output:
no
== Comment: #1 - Viktor Mihajlovski <[email protected]> - 2022-10-25
10:48:30 ==
Installing under z/VM leads to the same failure.
== Comment: #2 - Viktor Mihajlovski <[email protected]> - 2022-10-25
10:55:10 ==
I have captured a dump using virsh dump --memory-only. The output of crash
log is uploaded
== Comment: #7 - Harald Freudenberger <[email protected]> - 2022-10-26
07:33:52 ==
Looks like all ubuntu 18.04 installations on s390 are not working any more.
It is not an issue with z14 but z17 also fails to run a fresh installed
ubuntu 18.04.
== Comment: #8 - Harald Freudenberger <[email protected]> - 2022-10-26
08:25:52 ==
when I use the 'advanced installation' where I am able to choose the kernel
package and then choose the 4.15.0-50 generic the installed Ubuntu 18.04 comes
up fine. So this issue is somewhere between kernel 4.15.0-50 and 4.15.0-194.
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