[Bug 1623383] [NEW] Some restarts fail due to missing base devices

[Stefan Bader]

Public bug reported:

Arch: s390x
Release: Yakkety / 16.10

This happens on some (but not all) system starts with Yakkety. In Xenial
(which is using the same 4.4 kernel version the Yakkety systems were
using when the problem was first observed) this did not happen. The
system (LPAR) this was seen first was an upgrade from Xenial but since
then has been freshly installed with Yakkety. The same behaviour is seen
on a zVM guest running Yakkety.

The attached syslog shows a failed boot, followed by one that did work. Note the "Found device .*(sclp|encc00).*" messages in the good boot. Those are missing in the bad attempt and as a result networking and console fail to be usable. Also note, those boots were 4.8 kernels but we saw this with 4.4 kernels, too.
This might be a systemd problem / race, I just filed it into udev for now as that better matches the not finding basic devices symptom.

** Affects: udev (Ubuntu)
     Importance: Undecided
         Status: New

** Attachment added: "Bad and good boot logs"
   https://bugs.launchpad.net/bugs/1623383/+attachment/4740675/+files/syslog-20160914.txt

** Package changed: ubuntu => udev (Ubuntu)

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https://bugs.launchpad.net/bugs/1623383

Title:
  Some restarts fail due to missing base devices

Status in udev package in Ubuntu:
  New

Bug description:
  Arch: s390x
  Release: Yakkety / 16.10

  This happens on some (but not all) system starts with Yakkety. In
  Xenial (which is using the same 4.4 kernel version the Yakkety systems
  were using when the problem was first observed) this did not happen.
  The system (LPAR) this was seen first was an upgrade from Xenial but
  since then has been freshly installed with Yakkety. The same behaviour
  is seen on a zVM guest running Yakkety.

  The attached syslog shows a failed boot, followed by one that did work. Note the "Found device .*(sclp|encc00).*" messages in the good boot. Those are missing in the bad attempt and as a result networking and console fail to be usable. Also note, those boots were 4.8 kernels but we saw this with 4.4 kernels, too.
  This might be a systemd problem / race, I just filed it into udev for now as that better matches the not finding basic devices symptom.

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