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

[MegaBrutal]

** Description changed:

  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”.
+ 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.

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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:
  New
Status in ubuntu-release-upgrader package in Ubuntu:
  New

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.

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