[Bug 1511875] Re: Can't upgrade from 15.10 Wily to 16.04 Xenial in LXC container

[Jon Brase]

I'm running into the same thing trying to upgrade from 14.04 to 16.04.

After Googling around about the issue, this link at first looked like a
promising lead, as I'm running into this on Haswell hardware and I have
Core2 hardware that was unaffected:

https://groups.google.com/forum/#!topic/mechanical-sympathy/QbmpZxp6C64

So I tried using a custom-compiled 4.4 series kernel to see if that
resolved the issue, and it does cause the upgrade to stop hanging in the
futex wait channel, but, unfortunately, does not cause the upgrade to
stop hanging. On the 4.4 kernel, system monitor shows the process to be
in waiting channel 0 instead of the futex wait channel, but gdb shows
the process to be hung in "sem_wait()".

I am running into this on bare hardware, not a container or VM.

Given that I'm seeing it on a Haswell machine but my Core2 laptop did
not experience the hang, and given that using a newer kernel version
changed the specifics of how the hang is occuring, it seems to be
related to the kernel bug discussed at the Google Groups link above, but
the kernel bug can't be the whole story, or else the new kernel would
have fixed it.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to ubuntu-release-upgrader in
Ubuntu.
https://bugs.launchpad.net/bugs/1511875

Title:
  Can't upgrade from 15.10 Wily to 16.04 Xenial in LXC container

Status in lxc package in Ubuntu:
  Invalid
Status in ubuntu-release-upgrader package in Ubuntu:
  Triaged

Bug description:
  When I try to upgrade from 15.10 Wily to 16.04 Xenial (actual
  development version) within an LXC container, the upgrade script hangs
  at the message „Calculating the changes”.

  Steps to reproduce:
  1. Make an LXC container with Wily (quickest option is to use lxc-create -t download, choose ubuntu, wily, amd64/i386).
  2. Boot up the container, log in, „apt-get -y install ubuntu-release-upgrader-core”.
  3. Start the upgrade with „do-release-upgrade -d”.

  You will see that the upgrade process will hang at the message
  „Calculating the changes”.

  The process which hangs: „/usr/bin/python3 /tmp/ubuntu-release-
  upgrader-1mpotr5d/xenial --mode=server --frontend=DistUpgradeViewText
  --devel-release”

  With strace, it is revealed that the process hangs at a „futex” system call:
  futex(0x7f4190000c10, FUTEX_WAIT_PRIVATE, 0, NULL

  This system call never returns, the process must be interrupted with
  CTRL-C or kill.

  Upgrading to any previous release within an LXC container works
  without problems, therefore I consider it as a regression.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1511875/+subscriptions