Bug#991406: systemd: proc: unrecognized mount option "hidepid=invisible" or missing value

[Thomas Uhle]

Package: systemd
Version: 247.3-6
Severity: important

Dear maintainers,

after upgrading from buster to bullseye, I see the following error message 
in syslog multiple times (timestamp and host name stripped):

kernel: proc: unrecognized mount option "hidepid=invisible" or missing value

In some forum posts, it has been stated that it is due to 
/lib/systemd/systemd-remount-fs which seems to require a pretty recent 
Linux kernel like version 5.10 in bullseye. So everyone with a legacy 
kernel will get this error message in syslog several times because older 
kernels require a numerical value such as "hidepid=1" or "hidepid=2" 
instead of "hidepid=invisible".
Do you know whether this has already been fixed in a newer systemd version 
or whether this has already been dealt with upstream? I could not find 
anything with respect to this issue but I guess it should not be hard for 
a systemd developer to change systemd-remount-fs' behaviour depending on 
the running kernel version.
It really would be great if this could be fixed.

Thank you in advance!

Thomas Uhle


-- System Information:
Debian Release: 11.0
   APT prefers stable-updates
   APT policy: (500, 'stable-updates'), (500, 'testing'), (500, 'stable')
Architecture: arm64 (aarch64)
Foreign Architectures: armhf

Kernel: Linux 3.16.85-odroidc2 (SMP w/4 CPU threads; PREEMPT)
Kernel taint flags: TAINT_OOT_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), 
LANGUAGE=en_US.UTF-8
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages systemd depends on:
ii  adduser                          3.118
ii  libacl1                          2.2.53-10
ii  libapparmor1                     2.13.6-10
ii  libaudit1                        1:3.0-2
ii  libblkid1                        2.36.1-7
ii  libc6                            2.31-12
ii  libcap2                          1:2.44-1
ii  libcrypt1                        1:4.4.18-4
ii  libcryptsetup12                  2:2.3.5-1
ii  libgcrypt20                      1.8.7-6
ii  libgnutls30                      3.7.1-5
ii  libgpg-error0                    1.38-2
ii  libip4tc2                        1.8.7-1
ii  libkmod2                         28-1
ii  liblz4-1                         1.9.3-2
ii  liblzma5                         5.2.5-2
ii  libmount1                        2.36.1-7
ii  libpam0g                         1.4.0-9
ii  libseccomp2                      2.5.1-1
ii  libselinux1                      3.1-3
ii  libsystemd0                      247.3-6
ii  libzstd1                         1.4.8+dfsg-2.1
ii  mount                            2.36.1-7
ii  systemd-timesyncd [time-daemon]  247.3-6
ii  util-linux                       2.36.1-7

Versions of packages systemd recommends:
ii  dbus  1.12.20-2

Versions of packages systemd suggests:
ii  policykit-1        0.105-31
pn  systemd-container  <none>

Versions of packages systemd is related to:
pn  dracut           <none>
ii  initramfs-tools  0.140
ii  libnss-systemd   247.3-6
ii  libpam-systemd   247.3-6
ii  udev             247.3-6