Re: [PATCH 0/1] devpts: use dynamic_dname() to generate proc name

Christian Brauner
2017-08-23T21:15:42Z

On Wed, Aug 23, 2017 at 10:31:53AM -0500, Eric W. Biederman wrote:
> Christian Brauner <christian.brauner@canonical.com> writes:
>
> > On Wed, Aug 16, 2017 at 11:45 PM, Linus Torvalds
> > <torvalds@linux-foundation.org> wrote:
> >> On Wed, Aug 16, 2017 at 2:37 PM, Christian Brauner
> >> <christian.brauner@canonical.com> wrote:
> >>>> And Christian, if you can beat on this, that would be good.
> >>>
> >>> Yes, I can pound on this nicely with liblxc. We have patch
> >>> ( https://github.com/lxc/lxc/pull/1728 ) up for review that
> >>> allocates pty fds from private devpts mounts in different namespaces
> >>> and sends those fds around between different namespaces.
> >>
> >> Good. Testing that this works with different pts filesystems in
> >> different places is exactly the kind of thing I'd like to see. I only
> >> tested with my single pts filesystem that is mounted at /dev/pts, and
> >> making sure it works when there are multiple mounts and in different
> >> places is exactly the kind of testing this should get.
> >
> > I'm compiling a kernel now and depending on how good the in-flight
> > wifi is I try to test this right away and answer here if that helps. If the
> > in-flight wifi sucks it might take me until tomorrow.
>
> Linus has merged the fix but have you been able to test and verify all
> is well from your side?

Hi Eric,

Sorry for the late reply! So I've tested the patch and it does what I expect it
to do, i.e. it places the correct path as the content of /proc/<pid>/fd/<n>.
However, if I'm correct not in all cases. But I need to confirm this first and I
didn't want to start pointless discussions before having something reliable.
Thanks!

The reason for the late reply is that I was investigating some other "weirdness"
related to this patch which also - I believe - touches on the bind-mount
escaping you mentioned in your previous mail. It relates to an idea I had in
mind for a while now but never thought through sufficiently. I hope to find some
time on the weekend to think about this more clearly. I had hoped to bundle this
up with my testing but didn't get around to it.

Christian