'call-with-container' fails when CONFIG_DEVPTS_MULTIPLE_INSTANCES is not set

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Efraim Flashner
Ludovic Courtès

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Submitted by: Efraim Flashner

Severity: normal

Efraim Flashner wrote on 29 Nov 2015 19:29

silent failure on guix environment foo --container

Recipients:(address . bug-guix@gnu.org)

Message-ID:20151129202959.6a2f6053@debian-netbook

When trying to run `guix environment foo --container` I don't get a container

with a new shell or any useful information, it just thinks about it for a

while and then returns to the command prompt, allowing me to enter another

command.

efraim@debian-netbook:~$ strace -f -o log guix environment vim --container ; echo $?

efraim@debian-netbook:~$ uname -a

Linux debian-netbook 4.3-0.dmz.2-liquorix-amd64 #1 ZEN SMP PREEMPT Debian 4.3-2 (2015-11-17) x86_64 GNU/Linux

efraim@debian-netbook:~$ sudo sysctl -w kernel.unprivileged_userns_clone=1

sysctl: cannot stat /proc/sys/kernel/unprivileged_userns_clone: No such file or directory

(this kernel does allow running VMs as user, which makes it nice)

efraim@debian-netbook:~$ guix --version

guix (GNU Guix) 0.9.0

Efraim Flashner <efraim@flashner.co.il> ????? ?????

GPG key = A28B F40C 3E55 1372 662D 14F7 41AA E7DC CA3D 8351

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Attachment: log.gz

Ludovic Courtès wrote on 29 Nov 2015 22:20

Recipients:(name . Efraim Flashner)(address . efraim@flashner.co.il)

Message-ID:87k2p0fqou.fsf@gnu.org

Efraim Flashner <efraim@flashner.co.il> skribis:

Toggle quote (8 lines)

> When trying to run `guix environment foo --container` I don't get a container

> with a new shell or any useful information, it just thinks about it for a

> while and then returns to the command prompt, allowing me to enter another

> command.

> efraim@debian-netbook:~$ strace -f -o log guix environment vim --container ; echo $?

> 1

The failure is:

Toggle snippet (4 lines)

21228 mount("none", "/tmp/guix-directory.5sVcGc//dev/pts", "devpts", MS_NOSUID|MS_NOEXEC, "newinstance,ptmxmode=0666,mode=6"...) = -1 EPERM (Operation not permitted)

21228 exit_group(1) = ?

The problem may be that the kernel does not support

CONFIG_DEVPTS_MULTIPLE_INSTANCES. Could you check that in

/proc/config.gz or similar?

The other problem is that there’s no error reporting, which doubles user

frustration. David, could you look into it? :-)

Ludo’.

Efraim Flashner wrote on 30 Nov 2015 07:50

Recipients:(name . Ludovic Courtès)(address . ludo@gnu.org)

Message-ID:20151130085032.4b9c127e@debian-netbook

On Sun, 29 Nov 2015 22:20:33 +0100

ludo@gnu.org (Ludovic Courtès) wrote:

Toggle quote (15 lines)> Efraim Flashner <efraim@flashner.co.il> skribis:
> 
>  [...]  
> 
> The failure is:
> 
> --8<---------------cut here---------------start------------->8---
> 21228 mount("none", "/tmp/guix-directory.5sVcGc//dev/pts", "devpts", MS_NOSUID|MS_NOEXEC, "newinstance,ptmxmode=0666,mode=6"...) = -1 EPERM (Operation not permitted)
> 21228 exit_group(1)                     = ?
> --8<---------------cut here---------------end--------------->8---
> 
> The problem may be that the kernel does not support
> CONFIG_DEVPTS_MULTIPLE_INSTANCES.  Could you check that in
> /proc/config.gz or similar?

# CONFIG_DEVPTS_MULTIPLE_INSTANCES is not set

Toggle quote (8 lines)

> The other problem is that there’s no error reporting, which doubles user

> frustration. David, could you look into it? :-)

> Ludo’.

-- 
Efraim Flashner   <efraim@flashner.co.il>   ????? ?????
GPG key = A28B F40C 3E55 1372 662D  14F7 41AA E7DC CA3D 8351
Confidentiality cannot be guaranteed on emails sent or received unencrypted

Attachment: config.gz

Ludovic Courtès wrote on 30 Nov 2015 13:22

Recipients:(name . Efraim Flashner)(address . efraim@flashner.co.il)

Message-ID:8737vnekxh.fsf@gnu.org

Efraim Flashner <efraim@flashner.co.il> skribis:

Toggle quote (20 lines)> On Sun, 29 Nov 2015 22:20:33 +0100
> ludo@gnu.org (Ludovic Courtès) wrote:
>
>> Efraim Flashner <efraim@flashner.co.il> skribis:
>> 
>>  [...]  
>> 
>> The failure is:
>> 
>> --8<---------------cut here---------------start------------->8---
>> 21228 mount("none", "/tmp/guix-directory.5sVcGc//dev/pts", "devpts", MS_NOSUID|MS_NOEXEC, "newinstance,ptmxmode=0666,mode=6"...) = -1 EPERM (Operation not permitted)
>> 21228 exit_group(1)                     = ?
>> --8<---------------cut here---------------end--------------->8---
>> 
>> The problem may be that the kernel does not support
>> CONFIG_DEVPTS_MULTIPLE_INSTANCES.  Could you check that in
>> /proc/config.gz or similar?
>
> # CONFIG_DEVPTS_MULTIPLE_INSTANCES is not set

QED. :-) However, the daemon needs it too. Don’t you have problems

with guix-daemon as well, when building things locally on that machine?

Ludo’.

Efraim Flashner wrote on 30 Nov 2015 13:44

Recipients:(name . Ludovic Courtès)(address . ludo@gnu.org)

Message-ID:20151130144413.73383d40@debian-netbook

On Mon, 30 Nov 2015 13:22:34 +0100

ludo@gnu.org (Ludovic Courtès) wrote:

Toggle quote (27 lines)> Efraim Flashner <efraim@flashner.co.il> skribis:
> 
> > On Sun, 29 Nov 2015 22:20:33 +0100
> > ludo@gnu.org (Ludovic Courtès) wrote:
> >  
> >> Efraim Flashner <efraim@flashner.co.il> skribis:
> >> 
> >>  [...]  
> >> 
> >> The failure is:
> >> 
> >> --8<---------------cut here---------------start------------->8---
> >> 21228 mount("none", "/tmp/guix-directory.5sVcGc//dev/pts", "devpts", MS_NOSUID|MS_NOEXEC, "newinstance,ptmxmode=0666,mode=6"...) = -1 EPERM (Operation not permitted)
> >> 21228 exit_group(1)                     = ?
> >> --8<---------------cut here---------------end--------------->8---
> >> 
> >> The problem may be that the kernel does not support
> >> CONFIG_DEVPTS_MULTIPLE_INSTANCES.  Could you check that in
> >> /proc/config.gz or similar?  
> >
> > # CONFIG_DEVPTS_MULTIPLE_INSTANCES is not set  
> 
> QED.  :-)  However, the daemon needs it too.  Don’t you have problems
> with guix-daemon as well, when building things locally on that machine?
> 
> Ludo’.

Not at all, I've been building things all day. Is this the type of thing that
would control if there were multiple concurrent build processes? I've only
ever built things consecutively (not including make -j2). Without changing
settings, should I be building two packages concurrently, or building one and
downloading substitutes at the same time?

efraim@debian-netbook:~$ systemctl status guix-daemon.service
? guix-daemon.service - Guix daemon builds packges, installs them, and runs garbage collection.
   Loaded: loaded (/etc/systemd/system/guix-daemon.service; enabled; vendor preset: enabled)
   Active: active (running) since Sat 2015-11-28 21:36:22 IST; 1 day 17h ago
 Main PID: 810 (guix-daemon)
   CGroup: /system.slice/guix-daemon.service
           ??810 /root/.guix-profile/bin/guix-daemon --build-users-group=guix-builder

-- 
Efraim Flashner   <efraim@flashner.co.il>   ????? ?????
GPG key = A28B F40C 3E55 1372 662D  14F7 41AA E7DC CA3D 8351
Confidentiality cannot be guaranteed on emails sent or received unencrypted

Ludovic Courtès wrote on 30 Nov 2015 13:51

Recipients:(name . Efraim Flashner)(address . efraim@flashner.co.il)

Message-ID:87lh9fbqgv.fsf@gnu.org

Efraim Flashner <efraim@flashner.co.il> skribis:

Toggle quote (32 lines)> On Mon, 30 Nov 2015 13:22:34 +0100
> ludo@gnu.org (Ludovic Courtès) wrote:
>
>> Efraim Flashner <efraim@flashner.co.il> skribis:
>> 
>> > On Sun, 29 Nov 2015 22:20:33 +0100
>> > ludo@gnu.org (Ludovic Courtès) wrote:
>> >  
>> >> Efraim Flashner <efraim@flashner.co.il> skribis:
>> >> 
>> >>  [...]  
>> >> 
>> >> The failure is:
>> >> 
>> >> --8<---------------cut here---------------start------------->8---
>> >> 21228 mount("none", "/tmp/guix-directory.5sVcGc//dev/pts", "devpts", MS_NOSUID|MS_NOEXEC, "newinstance,ptmxmode=0666,mode=6"...) = -1 EPERM (Operation not permitted)
>> >> 21228 exit_group(1)                     = ?
>> >> --8<---------------cut here---------------end--------------->8---
>> >> 
>> >> The problem may be that the kernel does not support
>> >> CONFIG_DEVPTS_MULTIPLE_INSTANCES.  Could you check that in
>> >> /proc/config.gz or similar?  
>> >
>> > # CONFIG_DEVPTS_MULTIPLE_INSTANCES is not set  
>> 
>> QED.  :-)  However, the daemon needs it too.  Don’t you have problems
>> with guix-daemon as well, when building things locally on that machine?
>> 
>> Ludo’.
>
> Not at all, I've been building things all day.

I’ve realized that the daemon has a fallback case for this situation, in

libstore/build.cc:

Toggle snippet (18 lines)  /* Mount a new devpts on /dev/pts.  Note that this
     requires the kernel to be compiled with
     CONFIG_DEVPTS_MULTIPLE_INSTANCES=y (which is the case
     if /dev/ptx/ptmx exists). */
  if (pathExists("/dev/pts/ptmx") &&
      !pathExists(chrootRootDir + "/dev/ptmx")
      && dirsInChroot.find("/dev/pts") == dirsInChroot.end())
  {
      if (mount("none", (chrootRootDir + "/dev/pts").c_str(), "devpts", 0, "newinstance,mode=0620") == -1)
          throw SysError("mounting /dev/pts");
      createSymlink("/dev/pts/ptmx", chrootRootDir + "/dev/ptmx");

      /* Make sure /dev/pts/ptmx is world-writable.  With some
         Linux versions, it is created with permissions 0.  */
      chmod_(chrootRootDir + "/dev/pts/ptmx", 0666);
  }

David, should we do something similar?

Thanks,

Ludo’.

Ludovic Courtès wrote on 28 Feb 2016 19:00

retitle

Recipients:(address . request@debbugs.gnu.org)

Message-ID:87povgvhol.fsf@gnu.org

retitle 22053 'call-with-container' fails when CONFIG_DEVPTS_MULTIPLE_INSTANCES is not set

thanks

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