Bug#944586: udev: after upgrading to version 243-5, udev blocks the removal of lvm2 snapshots

[Antonio]

Package: udev
Version: 243-5
Severity: normal

Dear Maintainer,
after updating systemd to version 243-5, my backup procedures, which
include the use of snapshots on lvm2 logical volumes, were blocked
during the snapshot removal phase.

> create snapshot: OK
lvcreate --size 1G -s -n prova  system/doc

> no other action

> remove snapshot
lvremove -fv system/prova
    Archiving volume group "system" metadata (seqno 4031).
    Removing snapshot volume system/prova.
    Loading table for system-doc (251:7).
    Loading table for system-prova (251:12).
    Not monitoring system/prova with libdevmapper-event-lvm2snapshot.so
    Unmonitored
LVM-zKZzKzFy3LSl0iVHcy7DY8oSb1b6eCOf319azVbo42LDvCA6Bf1eoK6FoYY5r89e
for events
    Suspending system-doc (251:7) with device flush
    Suspending system-prova (251:12) with device flush
    Suspending system-doc-real (251:10) with device flush
    Suspending system-prova-cow (251:11) with device flush
    activation/volume_list configuration setting not defined: Checking
only host tags for system/prova.
    Resuming system-prova-cow (251:11).
    Resuming system-doc-real (251:10).
    Resuming system-prova (251:12).
    Removing system-prova-cow (251:11)
    Resuming system-doc (251:7).
    Removing system-doc-real (251:10)

> process is blocked
> now press ctrl-c for return in terminal

> but if I launch same command again:
 lvremove -fv system/prova
    Removing system-prova (251:12)
    Archiving volume group "system" metadata (seqno 4032).
    Releasing logical volume "prova"
    Creating volume group backup "/etc/lvm/backup/system" (seqno 4033).
  Logical volume "prova" successfully removed

> the internal actions are completed and the command then succeeds

> Reinstall stable or previous version solve the problem.
apt-get install udev=241-7~deb10u1 libudev1=241-7~deb10u1

# repeat test
lvcreate --size 1G -s -n prova  system/doc
  Logical volume "prova" created.
...
lvremove -fv system/prova
    Archiving volume group "system" metadata (seqno 4035).
    Removing snapshot volume system/prova.
    Loading table for system-doc (251:7).
    Loading table for system-prova (251:12).
    Not monitoring system/prova with libdevmapper-event-lvm2snapshot.so
    Unmonitored LVM-
zKZzKzFy3LSl0iVHcy7DY8oSb1b6eCOfO01gXwNkzP5AaYp6LZAx8b6nzUPILTAh for events
    Suspending system-doc (251:7) with device flush
    Suspending system-prova (251:12) with device flush
    Suspending system-doc-real (251:10) with device flush
    Suspending system-prova-cow (251:11) with device flush
    activation/volume_list configuration setting not defined: Checking only
host tags for system/prova.
    Resuming system-prova-cow (251:11).
    Resuming system-doc-real (251:10).
    Resuming system-prova (251:12).
    Removing system-prova-cow (251:11)
    Resuming system-doc (251:7).
    Removing system-doc-real (251:10)
    Removing system-prova (251:12)
    Releasing logical volume "prova"
    Creating volume group backup "/etc/lvm/backup/system" (seqno 4037).
  Logical volume "prova" successfully removed

> with the previous version everything was ok

Thanks,
Antonio


-- Package-specific info:

-- System Information:
Debian Release: bullseye/sid
  APT prefers unstable
  APT policy: (700, 'unstable'), (500, 'stable-updates'), (500,
'stable'), (100, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.3.10-custom (SMP w/8 CPU cores; PREEMPT)
Locale: LANG=it_IT, LC_CTYPE=it_IT (charmap=ISO-8859-1) (ignored:
LC_ALL set to it_IT), LANGUAGE=it (charmap=ISO-8859-1) (ignored:
LC_ALL set to it_IT)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages udev depends on:
ii  adduser       3.118
ii  dpkg          1.19.7
ii  libacl1       2.2.53-5
ii  libblkid1     2.34-0.1
ii  libc6         2.29-3
ii  libkmod2      26-3
ii  libselinux1   2.9-2+b2
ii  libudev1      243-5
ii  systemd-sysv  243-5
ii  util-linux    2.34-0.1

udev recommends no packages.

udev suggests no packages.

Versions of packages udev is related to:
ii  systemd  243-5

-- debconf information:
  udev/new_kernel_needed: false
  udev/title/upgrade:
  udev/reboot_needed:
  udev/sysfs_deprecated_incompatibility: