/dev/shm is not writable inside vivid chroot on trusty host

This problem is visible on a pool of pbuilder nodes. All of the slaves are amd64 running trusty. I can observe the issue when using pbuilder to mount a vivid chroot. The problem can be recognized by the fact that within the chroot, /dev/shm is not a link to /run/shm. See output below. This problem is only visible on a set of x86 hosts. I also have a set of armhf hosts (with armhf chroots). These armhf boxes do not show the problem.

This is only visible with vivid chroots. Trusty and utopic chroots show /dev/shm as a symlink to /run/shm.

All of the hosts have debootstrap 1.0.59ubuntu0.2. The amd64 nodes are running in openstack VMs, the armhf nodes are running on bare metal.

This appears to be a regression in behavior. The problem is impacting unit test cases in packages being built with the chroots. These test were working in the past, but the exact timeframe for when the problem was first observed is difficult to track down. Possible this has only been the case for about 2 months.

[On the amd64 host:]
$ ls -la /{dev,run}/sh*
lrwxrwxrwx 1 root root 8 Nov 26 21:15 /dev/shm -> /run/shm

/run/shm:
total 0
drwxrwxrwt 2 root root 40 Nov 26 21:19 .
drwxr-xr-x 21 root root 800 Dec 5 17:38 ..

[Inside the amd64 chroot:]
# ls -la /{dev,run}/sh*
/dev/shm:
total 8
drwxr-xr-x 2 root root 4096 Nov 26 21:31 .
drwxr-xr-x 4 root root 4096 Nov 26 21:31 ..

/run/shm:
total 4
drwxrwxrwt 2 root root 40 Dec 5 19:16 .
drwxr-xr-x 5 root root 4096 Nov 26 21:32 ..

[On the armhf host:]
$ ls -la /{dev,run}/sh*
lrwxrwxrwx 1 root root 8 Aug 9 05:08 /dev/shm -> /run/shm

/run/shm:
total 0
drwxrwxrwt 2 root root 40 Aug 9 05:08 .
drwxr-xr-x 17 root root 620 Dec 5 17:37 ..

[Inside the armhf chroot:]
# ls -la /{dev,run}/sh*
lrwxrwxrwx 1 root root 8 Oct 27 13:58 /dev/shm -> /run/shm

/run/shm:
total 4
drwxrwxrwt 2 root root 40 Dec 5 19:16 .
drwxr-xr-x 6 root root 4096 Oct 27 13:59 ..

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: debootstrap 1.0.59ubuntu0.2
ProcVersionSignature: Ubuntu 3.13.0-40.69-generic 3.13.11.10
Uname: Linux 3.13.0-40-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
Date: Fri Dec 5 19:14:23 2014
Ec2AMI: ami-00000052
Ec2AMIManifest: FIXME
Ec2AvailabilityZone: production
Ec2InstanceType: m1.jenkins.builder.prod
Ec2Kernel: aki-00000002
Ec2Ramdisk: ari-00000002
PackageArchitecture: all
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: debootstrap
UpgradeStatus: No upgrade log present (probably fresh install)