This bug seems to be caused by the way recursive bind mounting and unmounting works:
foo@sec-vivid-amd64:~$ grep home\/foo /proc/mounts /dev/loop0 /home/foo ext4 rw,relatime,data=ordered 0 0 foo@sec-vivid-amd64:~$ sudo mount -R /home /tmp/home foo@sec-vivid-amd64:~$ grep home\/foo /proc/mounts /dev/loop0 /home/foo ext4 rw,relatime,data=ordered 0 0 /dev/loop0 /tmp/home/foo ext4 rw,relatime,data=ordered 0 0 foo@sec-vivid-amd64:~$ sudo umount -R /tmp/home umount: /tmp/home/foo: target is busy (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1).) foo@sec-vivid-amd64:~$ grep home\/foo /proc/mounts /dev/loop0 /home/foo ext4 rw,relatime,data=ordered 0 0 /dev/loop0 /tmp/home/foo ext4 rw,relatime,data=ordered 0 0 -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to click in Ubuntu. https://bugs.launchpad.net/bugs/1427264 Title: using ecryptfs, creating frameworks fail to bind mount issues Status in click package in Ubuntu: New Bug description: Using vivid creating framework fails for ecryptfs users, the issue is similar to bug #769595 The userdir is mounted in a way which makes unmounts fail "E: 10mount: umount: /var/lib/schroot/mount/click-ubuntu-sdk-14.10 -armhf-ec6aaf62-31e0-47e9-b2f8-73f0b038fb4d/home/user: target is busy E: 10mount: (In some cases useful info about processes that E: 10mount: use the device is found by lsof(8) or fuser(1).) " changing the fstab line to be "/home/user /home/user none rw,bind 0 0" workarounds the issue To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/click/+bug/1427264/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp