Bug#931267: times out and drops into useless emergency shell with fsck still ongoing

[Steve McIntyre]

Package: systemd
Version: 241-5
Severity: important

Hi,

[ Ignore the system info etc. below - I'm running reportbug on a
  different system. ]

I've just dist-upgraded my headless home firewall/server from Stretch
to Buster. I did the usual task of config file merging. and then
rebooted the machine. It didn't come up on the network again
afterwards.

After rummaging around to connect a serial cable, there was no
interaction on the console so I rebooted again. Now I see that the
machine is running a fsck on the multiple large filesystems (Debian
mirror, video/audio data etc.) Fine - the machine had not been
rebooted in a long time, so the fsck was overdue. Then I see that
systemd has decided to time out startup of services and drop me into
an Emergency shell. With fsck going on and writing to the console, I
cannot useful interact with the shell. The fsck completed
successfully, but I had a headless machine that still needed
interaction to make it work again.

Several points/questions:

 * Why on earth do things have a short timeout when fsck is still
   running? It's normal for fsck on a large fs to take a long time,
   and this should not break bootup. Especially not on a headless box.

 * Why does systemd try to start an Emergency shell on an already-busy
   console? This is *not* useful.

 * I haven't tried to reproduce this, but the initial interaction on
   the console seemed to show a hung machine. I had no useful
   interaction there. Is the Emergency shell setup meant to prompt
   again on password failure if I just hit <enter> several times?
 
-- Package-specific info:

-- System Information:
Debian Release: 10.0
  APT prefers testing
  APT policy: (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-5-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en (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  2:2.1.0-5
ii  libgcrypt20      1.8.4-5
ii  libgnutls30      3.6.7-4
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      241-5
ii  mount            2.33.1-0.1
ii  util-linux       2.33.1-0.1

Versions of packages systemd recommends:
ii  dbus            1.12.16-1
ii  libpam-systemd  241-5

Versions of packages systemd suggests:
ii  policykit-1        0.105-25
ii  systemd-container  241-5

Versions of packages systemd is related to:
pn  dracut           <none>
ii  initramfs-tools  0.133
ii  udev             241-5

-- Configuration Files:
/etc/systemd/logind.conf changed [not included]

-- no debconf information