Bug#929150: systemd emergency mode: "systemctl default" and "exit" don't work

[--]

Package: systemd
Version: 241-3
Severity: important


1. Add this to /etc/fstab.
UUID=broken_uuid	/mnt	btrfs	defaults	0 0
2. Reboot.
3. Wait for the prompt "A start job is running".
4. Login. Type "systemctl default" or "exit" to boot into default mode.
5. The system does not start.


-- Package-specific info:

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-5-amd64 (SMP w/2 CPU cores)
Locale: LANG=it_IT.UTF-8, LC_CTYPE=it_IT.UTF-8 (charmap=UTF-8), LANGUAGE=it_IT.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages systemd depends on:
ii  adduser          3.118
ii  libacl1          2.2.53-4
ii  libapparmor1     2.13.2-10
ii  libaudit1        1:2.8.4-3
ii  libblkid1        2.33.1-0.1
ii  libc6            2.28-10
ii  libcap2          1:2.25-2
ii  libcryptsetup12  2:2.1.0-3
ii  libgcrypt20      1.8.4-5
ii  libgnutls30      3.6.6-2
ii  libgpg-error0    1.35-1
ii  libidn11         1.33-2.2
ii  libip4tc0        1.8.2-4
ii  libkmod2         26-1
ii  liblz4-1         1.8.3-1
ii  liblzma5         5.2.4-1
ii  libmount1        2.33.1-0.1
ii  libpam0g         1.3.1-5
ii  libseccomp2      2.3.3-4
ii  libselinux1      2.8-1+b1
ii  libsystemd0      241-3
ii  mount            2.33.1-0.1
ii  util-linux       2.33.1-0.1

Versions of packages systemd recommends:
ii  dbus            1.12.12-1
ii  libpam-systemd  241-3

Versions of packages systemd suggests:
ii  policykit-1        0.105-25
pn  systemd-container  <none>

Versions of packages systemd is related to:
pn  dracut           <none>
ii  initramfs-tools  0.133
ii  udev             241-3

-- no debconf information