To be honest I don't know if this is the cases, but at least it looks related. The backport in this case may not be that easy, so let's do some debugging first.
If you have a reproducer, can you please switch systemd log level to debug
systemd-analyze set-log-level debug
reproduce the issue and send us the output of journal
Created attachment 1334156 [details]
root@172: /tmp # systemctl -pLogLevel show
Failed to get properties: Connection timed out
root@172: /tmp # systemd-analyze set-log-level debug
Failed to issue method call: Activation of org.freedesktop.systemd1 timed out
"journalctl -b" attached, but likely with LogLevel info
From what I've seen on the test system you've hit this bug,
Reproducer is very straight forward,
systemctl mask proc-sys-fs-binfmt_misc.automount
ls -l /proc/sys/fs/binfmt_misc
Blocking that you see is due to unhandled autofs events. Obviously, systemd can't handle them because it crashed.
This was fixed upstream a while ago,
Here is backport for RHEL-7 (it wasn't as straightforward as I'd like so it will require proper review).
And here is scratch build with backport,
Thanks for getting this out so fast. Upgraded systemd-*, systemd-sysv-* and systemd-libs-* on the affected system. While this helped with the debian reproducer, df still hanged. Resorted to "systemctl mask proc-sys-fs-binfmt_misc.automount", no more df hangs at the moment.
fix merged to staging branch -> https://github.com/lnykryn/systemd-rhel/pull/154 -> post
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.