[Debian-ports-devel] Error "The system has no more ptys" when running expect

[John Paul Adrian Glaubitz]

Hi!

I have been running into problems with pseudo-terminals on sparc64 when
building things like gcc-5, gcc-6 [1]:

-----------------------------------------------------------------------------

The system has no more ptys.  Ask your system administrator to create more.
    while executing
"spawn true"
expect is failing on your system with the above error, which means the GCC
testsuite will fail.  Please resolve the above issues and retry the build.
-----------------------------------------------------------------------------

Looking into into the schroot configuration, /dev/pts is mounted in the schroot:

root at landau:~# mount |grep pts
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
devpts on /run/schroot/mount/sid3-sparc64-sbuild-efb85ed4-4d23-4cc8-af46-ef4325a33199/dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
devpts on /run/schroot/mount/sid2-sparc64-sbuild-dc48ff2f-c9c8-4a2d-8823-a21acefa00df/dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
root at landau:~#

The fstab for the buildd profile looks correct as far as I can see:

root at landau:~# cat /etc/schroot/buildd/fstab
# fstab: static file system information for chroots.
# Note that the mount point will be prefixed by the chroot path
# (CHROOT_PATH)
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/proc           /proc           none    rw,bind         0       0
/sys            /sys            none    rw,bind         0       0
/dev/pts        /dev/pts        none    rw,bind         0       0
tmpfs           /dev/shm        tmpfs   defaults        0       0
# Mount a large scratch space for the build, so we don't use up
# space on an LVM snapshot of the chroot itself.
#/var/lib/sbuild/build  /build   none    rw,bind         0       0
root at landau:~#

And the number of available ptys in the schroot looks fine, too:

root at landau:~# schroot -c sid1-sparc64-sbuild
(sid1-sparc64-sbuild)root at landau:~# cat /proc/sys/kernel/pty/max
4096
(sid1-sparc64-sbuild)root at landau:~#

Could it be a possible permissions problem? Does "buildd" have to be in the
group "tty" (gid 5)? Or is it possible that on a system with four parallel
buildd instances, the maximum number of TTYs has to be more than 4096?

Adrian

> [1] https://buildd.debian.org/status/fetch.php?pkg=gcc-5&arch=sparc64&ver=5.4.0-2&stamp=1464995190

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913