Bug#1093674: Recent changes in device naming broke multiple applications

[Petter H]

Package: udev
Version: 252.33-1~deb12u1

At some point between mid October 2024 and now (20 Jan 2025), multiple 
device naming behaviors changed in Debian stable, breaking networking 
configuration and libpam-mount (probably other things are broken as 
well). Output from df also changed.

df now outputs e.g., /dev/dm-2 instead of /dev/mapper/_dev_sdb in its 
first column for a luks encrypted disk.

df -h | grep /mnt

old:
/dev/mapper/_dev_sdb   932G  530G  402G  57% /mnt

new:
/dev/dm-3              932G  530G  402G  57% /mnt

df output change broke a script (the df behavior prior to the breaking 
change [above] was reversed from this script line):
   old script line before device naming changes that affected df:
     devmapper_dev="$(df "$TARGET_MNTPOINT" | awk 
'/^\/dev\/mapper\//{print $1}')"


libpam-mount is broken (presumably) by the same change that changed the 
output of df.  So, umount no longer will automatically close the luks 
device when running umount.

This used to be sufficient, after installing libpam-mount:
(given a disk, /dev/sdb that is encrypted with luks, with a filesystem 
created on top)
mount /dev/sdb /mnt
(prompted for luks password)
...
umount /mnt
(at this point, before the breaking change, the luks device was auto 
closed, by libpam-mount)
Now it is necessary to manually run, after 'umount /mnt':
cryptsetup luksClose _dev_sdb


Also, during the same period, network devices named 'usbN' suddenly 
changed to being called 'ethN', breaking existing network configuration 
(using net.ifnames=0).

Because the root issue appears to be device naming behavior changes for 
all these issues, I am assuming the root cause is a udev change. If you 
feel this bug belongs somewhere else, please re-assign.

Linux nim 6.1.0-30-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.124-1 
(2025-01-12) x86_64 GNU/Linux

libc6:amd64    2.36-9+deb12u9
coreutils      9.1-1

udev upgrade history between last known working state, and current 
broken state:
2025-01-11  15:21:06  udev:amd64 (252.31-1~deb12u1, 252.33-1~deb12u1)
2024-11-09  17:29:35  udev:amd64 (252.30-1~deb12u2, 252.31-1~deb12u1)