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Re: [Bug 1263738] Re: login console 0 in user namespace container is not configured right

 

On Tue, Jan 14, 2014 at 08:42:06PM -0000, Serge Hallyn wrote:
> Note that what you describe should also be the case if using a regular
> container
> 
> 	sudo lxc-create -t ubuntu-cloud -n u1
> 	sudo lxc-start -n u1
> 
> Is the process group of init somehow ending up different in the user
> namespace case?  Or else why would this only be a problem in the
> user namespace case?

It is diffferent. Here's the controlling ttys without user namespaces:

ubuntu@u1:~$ cat /proc/$$/stat | cut -d' ' -f7
34826
ubuntu@u1:~$ cat /proc/1/stat | cut -d' ' -f7
0

and with user namsepaces:

ubuntu@c1:~$ cat /proc/$$/stat | cut -d' ' -f7
0
ubuntu@c1:~$ cat /proc/1/stat | cut -d' ' -f7
34826

init should have its controlling terminal cleared when it calls
setsid(), so either it isn't calling setsid() or else setsid() is
failing. The reasons setsid() would fail are that the process is already
a session group leader or else a session with the same id already
exists. I haven't found how user namespaces would have any effect on
those things, however.

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https://bugs.launchpad.net/bugs/1263738

Title:
  login console 0 in user namespace container is not configured right

Status in “linux” package in Ubuntu:
  Confirmed
Status in “lxc” package in Ubuntu:
  Triaged
Status in “linux” source package in Trusty:
  Confirmed
Status in “lxc” source package in Trusty:
  Triaged

Bug description:
  When you create a container in a private user namespace, when you start the
  container without the '-d' flag, that console is not properly set up.  Logging in
  gives you

  -bash: no job control in this shell

  and hitting ctrl-c reboots the container.

  Consoles from 'lxc-console -n $container' behave correctly.

  This may be a kernel issue, as discussed here:

  http://lists.linuxcontainers.org/pipermail/lxc-
  devel/2013-October/005843.html

  so also marking this as affecting the kernel.

  This can be worked around, but really needs to be fixed before trusty
  is frozen.

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References