$ sudo click chroot -a armhf -f ubuntu-sdk-15.04 destroy
[sudo] contrasenaya per a dpm: 
Traceback (most recent call last):
  File "/usr/bin/click", line 110, in <module>
    sys.exit(main())
  File "/usr/bin/click", line 106, in main
    return mod.run(args)
  File "/usr/lib/python3/dist-packages/click/commands/chroot.py", line 266, in run
    return args.func(parser, args)
  File "/usr/lib/python3/dist-packages/click/commands/chroot.py", line 91, in destroy
    return chroot.destroy()
  File "/usr/lib/python3/dist-packages/click/chroot.py", line 694, in destroy
    shutil.rmtree(chroot_dir)
  File "/usr/lib/python3.5/shutil.py", line 474, in rmtree
    _rmtree_safe_fd(fd, path, onerror)
  File "/usr/lib/python3.5/shutil.py", line 416, in _rmtree_safe_fd
    onerror(os.rmdir, fullname, sys.exc_info())
  File "/usr/lib/python3.5/shutil.py", line 414, in _rmtree_safe_fd
    os.rmdir(name, dir_fd=topfd)
OSError: [Errno 16] Device or resource busy: 'tmp'