kernel panic on booting kernel 4.4 based d-i from 16.04.5 RC image

Bug #1784454 reported by Frank Heimes on 2018-07-30
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Ubuntu on IBM z Systems
debian-installer (Ubuntu)
Canonical Foundations Team
linux (Ubuntu)
Canonical Kernel Team
systemd (Ubuntu)
Canonical Foundations Team

Bug Description

Booting d-i based on kernel 4.4 (from ./boot folder) from the 16.04.5 RC image on a z/VM guest
leads to a kernel panic:

/lib/debian-installer/start-udev: line 15: can't create /sys/module/scsi_mod/par
ameters/scan: Permission denied
¬ 0.845071| Kernel panic - not syncing: Attempted to kill initÜ exitcode=0x00
¬ 0.845071|
¬ 0.845075| CPU: 0 PID: 1 Comm: /init Not tainted 4.4.0-131-generic #157-Ubun
¬ 0.845077| 000000007d107c20 000000007d107cb0 0000000000000002 0000000
       000000007d107d50 000000007d107cc8 000000007d107cc8 0000000000114732
       000000000000008b 00000000009a304c 00000000009f11d0 000000000000000b
       000000007d107d10 000000007d107cb0 0000000000000000 0000000000000000
       0400000001cdf800 0000000000114732 000000007d107cb0 000000007d107d10
¬ 0.845089| Call Trace:
¬ 0.845093| (¬<000000000011461a>| show_trace+0xfa/0x150)
¬ 0.845095| ¬<00000000001146e2>| show_stack+0x72/0xf8
¬ 0.845099| ¬<0000000000555752>| dump_stack+0x82/0xb8
¬ 0.845101| ¬<0000000000286390>| panic+0x108/0x250
¬ 0.845104| ¬<0000000000166228>| do_exit+0xac0/0xba0
¬ 0.845106| ¬<00000000001663c8>| do_group_exit+0x50/0xe0
¬ 0.845108| ¬<0000000000166488>| __wake_up_parent+0x0/0x28
¬ 0.845111| ¬<00000000007eadda>| system_call+0xee/0x28c
¬ 0.845113| ¬<000003ff8953983a>| 0x3ff8953983a
00: HCPGIR450W CP entered; disabled wait PSW 00020001 80000000 00000000 0010F8CA

Dimitri John Ledkov (xnox) wrote :

13: if [ -f /sys/module/scsi_mod/parameters/scan ]; then
14: echo sync > /sys/module/scsi_mod/parameters/scan
15: fi

Not sure how come the file is there, yet "cannot be created" when we try to echo into it... maybe it's not writable or disappears.

I think the quickest botch that i can think of is:

   echo sync > /sys/module/scsi_mod/parameters/scan 2>/dev/null || :

to redirect errors to oblivion, and to ignore errors from this action....

Changed in debian-installer (Ubuntu):
assignee: nobody → Canonical Foundations Team (canonical-foundations)
Changed in systemd (Ubuntu):
assignee: nobody → Canonical Foundations Team (canonical-foundations)
Changed in debian-installer (Ubuntu):
importance: Undecided → Critical
Changed in systemd (Ubuntu):
importance: Undecided → Critical
Frank Heimes (frank-heimes) wrote :

btw. d-i based on hwe kernel 4.15 (boot-hwe) works fine ...

Ubuntu QA Website (ubuntuqa) wrote :

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:

tags: added: iso-testing
tags: added: kernel-key
Changed in linux (Ubuntu):
status: New → Triaged
importance: Undecided → Critical
assignee: nobody → Canonical Kernel Team (canonical-kernel-team)
Steve Langasek (vorlon) on 2018-07-30
Changed in debian-installer (Ubuntu):
milestone: none → ubuntu-16.04.5
Carla Sella (carla-sella) wrote :

Hello Frank, or anyone else affected,

Accepted systemd into xenial-proposed. The package will build now and be available at in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at . Thank you in advance!

Changed in systemd (Ubuntu Xenial):
status: New → Fix Committed
tags: added: verification-needed verification-needed-xenial
Changed in linux (Ubuntu):
status: Triaged → Invalid
no longer affects: ubuntu-z-systems
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package systemd - 229-4ubuntu21.4

systemd (229-4ubuntu21.4) xenial; urgency=medium

  * debian/extra/start-udev: test that sync parameters file is writable, before
    writing to it. On old kernels (e.g. v4.4) the file is available but is
    read-only, thus writing to it causes init to fail and thus raise a kernel
    panic. As an extra caution ignore failures to write into that file anyway,
    since synchronous scsi probing is not critical enough to prevent starting
    d-i. LP: #1784454

 -- Dimitri John Ledkov <email address hidden> Mon, 30 Jul 2018 19:58:15 +0100

Changed in systemd (Ubuntu Xenial):
status: Fix Committed → Fix Released
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package debian-installer - 20101020ubuntu451.26

debian-installer (20101020ubuntu451.26) xenial; urgency=medium

  * Rebuild against new systemd for the 4.4 kernel regression fix (LP: #1784454)

 -- Łukasz 'sil2100' Zemczak <email address hidden> Mon, 30 Jul 2018 22:26:39 +0200

Changed in debian-installer (Ubuntu):
status: New → Fix Released
Frank Heimes (frank-heimes) wrote :

I can confirm that the updated installer taken from here:
now properly works and boots.

Setting the tags accordingly.

tags: added: verification-done verification-done-xenial
removed: verification-needed verification-needed-xenial
Frank Heimes (frank-heimes) wrote :

Looks like the fixed installer was already included into the todays ISO:
I can confirm that this works, too (adding a 'pass' to the QA tracker)

Changed in ubuntu-z-systems:
status: New → Fix Released
importance: Undecided → Critical
Łukasz Zemczak (sil2100) wrote :

Thanks for verifying!

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