Bug#859766: pbuilder does not umount dev/ptmx in chroot / cached chroot not removed

[Patrick Matthäi]

Package: pbuilder
Version: 0.228.6
Severity: important

Hello,

since the last jessie-bpo update (so I am using 0.228.6~bpo8+1) pbuilder does
not umount dev/ptmx in the chroot, which ends up in this:

# mount |grep pbuilder
devpts on /var/cache/pbuilder/build/2180/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/22434/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/15332/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/16325/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/2582/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/11269/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/12795/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/4676/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/5997/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
devpts on /var/cache/pbuilder/build/23004/dev/ptmx type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)

# du -sh /var/cache/pbuilder/build/
5,2G    /var/cache/pbuilder/build/

It happens on --update and --build and this is the message from pbuilder itself:

I: copying local configuration
I: Copying back the cached apt archive contents
I: unmounting dev/pts filesystem
I: unmounting dev/shm filesystem
I: unmounting proc filesystem
I: unmounting sys filesystem
E: Something is still mounted under /var/cache/pbuilder/build/31706; unmount and remove /var/cache/pbuilder/build/31706 manually
I: Current time: Fri Apr  7 10:49:02 CEST 2017
I: pbuilder-time-stamp: 1491554942


-- System Information:
Debian Release: 8.7
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages pbuilder depends on:
ii  debconf [debconf-2.0]  1.5.56
ii  debootstrap            1.0.67
ii  dpkg-dev               1.17.27
ii  initscripts            2.88dsf-59
ii  util-linux             2.25.2-6
ii  wget                   1.16-1+deb8u1

Versions of packages pbuilder recommends:
ii  devscripts  2.15.3+deb8u1
pn  eatmydata   <none>
ii  fakeroot    1.20.2-1
ii  iproute2    3.16.0-2
ii  net-tools   1.60-26+b1
ii  sudo        1.8.10p3-1+deb8u3

Versions of packages pbuilder suggests:
pn  cowdancer   <none>
pn  gdebi-core  <none>

-- debconf information excluded