Subject: Re: [vserver] problem with devpts
From: Herbert Poetzl <herbert@13thfloor.at>
Date: Mon, 17 May 2010 19:54:45 +0200

On Mon, May 17, 2010 at 05:36:17PM +0300, Deniss wrote:

> Herbert Poetzl wrote:
> >On Fri, May 07, 2010 at 03:17:04PM +0300, Deniss wrote:
> >>yeh, looks like the problem is in vprocunhide - when problem arise in
> >>already open session to guest `ps` stop working

> >>www ~ # ps -efH
> >>Error, do this: mount -t proc proc /proc

> >>when i enter to guset using 'vserver enter' the problem disappears - 
> >>proc is mounted and ssh working

> >util-vserver version?
> zavarka ~ # vserver-info
> Versions:
>                    Kernel: 2.6.32.12-vs2.3.0.36.29.4-vserver-intel
>                    VS-API: 0x00020305
>              util-vserver: 0.30.216-pre2883; Apr 15 2010, 14:13:08
> 
> Features:
>                        CC: i686-pc-linux-gnu-gcc, i686-pc-linux-gnu-gcc 
> (Gentoo 4.3.4 p1.0, pie-10.1.5) 4.3.4
>                       CXX: i686-pc-linux-gnu-g++, i686-pc-linux-gnu-g++ 
> (Gentoo 4.3.4 p1.0, pie-10.1.5) 4.3.4
>                  CPPFLAGS: ''
>                    CFLAGS: '-O2 -mtune=native -march=native -pipe 
> -fomit-frame-pointer -std=c99 -Wall -pedantic -W -funit-at-a-time'
>                  CXXFLAGS: '-O2 -mtune=native -march=native -pipe 
> -fomit-frame-pointer -ansi -Wall -pedantic -W -fmessage-length=0 
> -funit-at-a-time'
>                build/host: i686-pc-linux-gnu/i686-pc-linux-gnu
>              Use dietlibc: yes
>        Build C++ programs: yes
>        Build C99 programs: yes
>            Available APIs: v13,net,v21,v22,v23,netv2
>             ext2fs Source: e2fsprogs
>     syscall(2) invocation: alternative
>       vserver(2) syscall#: 273/glibc
>                crypto api: beecrypt
>           python bindings: yes
>    use library versioning: yes
> 
> Paths:
>                    prefix: /usr
>         sysconf-Directory: /etc
>             cfg-Directory: /etc/vservers
>          initrd-Directory: $(sysconfdir)/init.d
>        pkgstate-Directory: /var/run/vservers
>           vserver-Rootdir: /vservers

> >>Deniss wrote:
> >>>hello !

> >>>i have a problem with devpts on 2.6.32.12-vs2.3.0.36.29.4:
> >>>sometimes sshd stop allowing to log in with errors:

> >does it happen on a more recent kernel/patch too?

> I running 
> http://people.linux-vserver.org/~harry/patch-2.6.32.12-vs2.3.0.36.29.4-grsec2.1.14-20100503.diff

maybe the issue is grsec related?
if you can easily reproduce it, please try without the
grsec patch and let us know how that goes ...

TIA,
Herbert

> that is the latest one patch

> Note that the problem happens after some time after guest start, and
> it is enough to run "vprocunhide" again to fix it

> >TIA,
> >Herbert

> >>>May  7 11:01:28 www sshd[1520]: fatal: openpty returns device for which 
> >>>ttyname fails.
> >>>May  7 11:01:28 www sshd[1520]: error: chown  0 0 failed: No such file 
> >>>or directory
> >>>May  7 11:01:28 www sshd[1520]: error: chmod  0666 failed: No such file 
> >>>or directory
> >
> >>>restarting sshd helps
> >
> >>>i think the problem may be in context leak between host and guest cos 
> >>>they share /dev/pts as i understand
> >
> >>>probably the solution may be to use "newinstance" feature of devpts but 
> >>>i cant manage to get it working.