Bug#935471: systemd: bogus "Process .. as been marked to be excluded from killing" warning from systemd-shutdown

[Marc Lehmann]

Package: systemd
Version: 241-5
Severity: minor

Dear Maintainer,

on one of my systems, debian runs from a filesystem image loop-mounted
from an ntfs volume using ntfs-3g, and thus, the ntfs-3g process must be
running at all times, before mounting the root fs and during shutdown.

To accomplish this I have an initramfs-tools script that runs it something
like this:

  exec -a @ntfs-3g-root ntfs-3g ...

The @ prevents systemd-shutdown from killing it, which works. However, it
outputs the following warning (lifted from the code, can't copy&paste from
the real system):

                log_notice("Process " PID_FMT " (%s) has been marked to be excluded from killing. It is "
                           "running from the root file system, and thus likely to block re-mounting of the "
                           "root file system to read-only. Please consider moving it into an initrd file "
                           "system instead.", pid, strna(comm));

Since it is running from the initramfs, this warning is bogus (and indeed,
the root fs can be mounted ro with no problem), suggesting that the check
systemd-shutdown uses to detect this case is broken.

For additional reference, /proc/<ntfs-3g-pid>/root has a target of "/",
which probably causes this. /proc/<ntfs-3g-pid>/exe has a target of
'/usr/bin/ntfs-3g (deleted)', which makes sense as it was deleted when
cleaning up the initramfs before handing over to the actual root fs.

-- Package-specific info:

-- System Information:
Debian Release: 10.0
  APT prefers stable
  APT policy: (990, 'stable'), (500, 'unstable-debug'), (500, 'testing-debug'), (500, 'stable-updates'), (500, 'stable-debug'), (500, 'oldstable-updates'), (500, 'oldstable-debug'), (500, 'unstable'), (500, 'testing'), (500, 'oldstable'), (1, 'experimental-debug'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, x32

Kernel: Linux 5.1.21-050121-generic (SMP w/8 CPU cores)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_DK.UTF-8, LC_CTYPE=en_DK.UTF-8 (charmap=UTF-8), LANGUAGE=en_DK.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  2:2.1.0-5
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
pn  systemd-container  <none>

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

-- no debconf information