P8 node entei unable to boot with 4.15.0-141.145~16.04.1

Bug #1922997 reported by Po-Hsu Lin on 2021-04-08
10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
ubuntu-kernel-tests
Undecided
Unassigned
linux-hwe (Ubuntu)
Undecided
Unassigned
Xenial
Undecided
Unassigned

Bug Description

[Impact]
Enabling CONFIG_MODVERSIONS on xenial/linux-hwe (via rebase on bionic/linux, see bug 1898716) is causing the kernel to fail booting on ppc64el as the modules can't be loaded because of the mismatch of the module_layout symbol.

[ 7.635173] raid0: disagrees about version of symbol module_layout

[Fix]
The proposed fix is to disable CONFIG_MODVERSIONS and unset CONFIG_SYSTEM_TRUSTED_KEYS via the 'local-mangle' script which gets called by the 'open' script after the rebase. Making the changes directly on the config or annotations file is not persistent as these files are synced from master.

This is a temporary fix until the root cause can be found.

[Test case]
Boot the kernel on a xenial ppc64el system.

[Regression potential]
This config option has been enabled on Bionic to support rebuilding the lrm modules without the need to rebuild the kernel. There are no lrm modules in Xenial, so it should be safe to keep it disabled.

[Original Description]

Tested manually, this node can boot with 4.15.0-140-generic

However with 4.15.0-141.145~16.04.1 in proposed, it will drop into initramfs:

[ 9.547985] usb 1-3.4: Manufacturer: American Megatrends Inc.
[ 9.563800] hid: disagrees about version of symbol module_layout
[ 9.563949] hid: disagrees about version of symbol module_layout
[ 9.692066] libcrc32c: disagrees about version of symbol module_layout
[ 12.593593] raid10: disagrees about version of symbol module_layout
done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done.
Begin: Running /scripts/local-premount ... [ 12.963251] raid6_pq: disagrees about version of symbol module_layout
done.
Begin: Waiting for root file system ... Begin: Running /scripts/local-block ... mdadm: CREATE group disk not found
mdadm: No devices listed in conf file were found.
done.
Begin: Running /scripts/local-block ... mdadm: CREATE group disk not found
mdadm: No devices listed in conf file were found.
done.
(this mdadm message repeats)
Gave up waiting for root device. Common problems:
 - Boot args (cat /proc/cmdline)
   - Check rootdelay= (did the system wait long enough?)
   - Check root= (did the system wait for the right device?)
 - Missing modules (cat /proc/modules; ls /dev)
ALERT! UUID=348b5e78-915d-47b0-93db-3eca0d8f048e does not exist. Dropping to a shell!
[ 204.831089] hid: disagrees about version of symbol module_layout

BusyBox v1.22.1 (Ubuntu 1:1.22.0-15ubuntu1.4) built-in shell (ash)
Enter 'help' for a list of built-in commands.

(initramfs)

Please find attachment for the boot log.

Po-Hsu Lin (cypressyew) wrote :
description: updated
Po-Hsu Lin (cypressyew) wrote :

boot dmesg for 4.15.0-140-generic #144~16.04.1-Ubuntu

Changed in linux-hwe (Ubuntu Xenial):
status: New → Confirmed
Changed in linux-hwe (Ubuntu):
status: New → Invalid
description: updated
description: updated
Changed in linux-hwe (Ubuntu Xenial):
status: Confirmed → In Progress
description: updated
Changed in linux-hwe (Ubuntu Xenial):
status: In Progress → Fix Committed
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