Comment 4 for bug 1980951

------- Comment From <email address hidden> 2022-07-08 13:23 EDT-------
(In reply to comment #7)
> A patched jammy kernel 5.15 test build in PPA is available here:
> https://launchpad.net/~fheimes/+archive/ubuntu/lp1980951

I successfully verified that the PPA kernel fixes the problem:

Without fix
===========

root@localhost:~# uname -a
Linux localhost 5.15.0-40-generic #43-Ubuntu SMP Wed Jun 15 12:53:53 UTC 2022 s390x s390x s390x GNU/Linux
root@localhost:~# lscss | wc -l
6
root@localhost:~# dmesg -c >/dev/null
root@localhost:~# echo free all >/proc/cio_ignore
root@localhost:~# dmesg | head -n 5
[ 91.836284] Unable to handle kernel pointer dereference in virtual kernel address space
[ 91.836300] Failing address: 6370753837000000 TEID: 6370753837000803
[ 91.836305] Fault in home space mode while using kernel ASCE.
[ 91.836311] AS:000000000a9e8007 R3:0000000000000024
[ 91.836494] Oops: 0038 ilc:3 [#1] SMP
root@localhost:~# lscss | wc -l
6

With fix applied
================

root@localhost:~# uname -a
Linux localhost 5.15.0-41-generic #44~lp1980951-Ubuntu SMP Thu Jul 7 14:31:02 UTC 2022 s390x s390x s390x GNU/Linux
root@localhost:~# lscss | wc -l
6
root@localhost:~# dmesg -c >/dev/null
root@localhost:~# echo free all >/proc/cio_ignore
root@localhost:~# dmesg
root@localhost:~# lscss | wc -l
2961