Bug#856337: systemd: please support kernel 4.4, or don't hardcode dm interface versions

[Marc Lehmann]

Package: systemd
Version: 232-18
Severity: normal

Dear Maintainer,

I upgraded to stretch, using kernel 4.4.47. When rebooting, system could
not clean up device mapper targets, leading to a hard crash for all cache
targets, requiring many hours of heavy I/O after bootup and creating a
high-risk window for data corruption.

The specific error I got was something like (from memory):

   Could not detach DM dm-11: ioctl mismatch, kernel(4.34.4), user(4.35.4)

Since kernel 4.4 was until very recently the newest longterm stable kernel
and 4.9 has many issues (most notably btrfs losing files), it would be
extremely appreciated if 4.4 would still be supported in stretch, at least
until the newer kernel versions stabilise.

Alternatively, since lvm and dmsetup from stretch do not have any issues
with kernel 4.4, I suspect systemd hardcodes version numbers in direct
calls instead of going through e.g. libdevmapper - going through a library
such as libdevmapper that hanmdles the kernel versions bettrer would also
take care of this issue, at least for current stretch.

Thanks for your consideration.

-- Package-specific info:

-- System Information:
Debian Release: 9.0
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.4.47-040447-generic (SMP w/8 CPU cores)
Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: systemd (via /run/systemd/system)

Versions of packages systemd depends on:
ii  adduser         3.115
ii  libacl1         2.2.52-3+b1
ii  libapparmor1    2.11.0-2
ii  libaudit1       1:2.6.7-1
ii  libblkid1       2.29.1-1
ii  libc6           2.24-9
ii  libcap2         1:2.25-1
ii  libcryptsetup4  2:1.7.3-3
ii  libgcrypt20     1.7.6-1
ii  libgpg-error0   1.26-2
ii  libidn11        1.33-1
ii  libip4tc0       1.6.0+snapshot20161117-5
ii  libkmod2        23-2
ii  liblz4-1        0.0~r131-2+b1
ii  liblzma5        5.2.2-1.2+b1
ii  libmount1       2.29.1-1
ii  libpam0g        1.1.8-3.5
ii  libseccomp2     2.3.1-2.1
ii  libselinux1     2.6-3
ii  libsystemd0     232-18
ii  mount           2.29.1-1
ii  util-linux      2.29.1-1

Versions of packages systemd recommends:
ii  dbus            1.10.16-1
ii  libpam-systemd  232-18

Versions of packages systemd suggests:
ii  policykit-1        0.105-17
pn  systemd-container  <none>
ii  systemd-ui         3-4

Versions of packages systemd is related to:
pn  dracut           <none>
ii  initramfs-tools  0.127
ii  udev             232-18

-- Configuration Files:
/etc/systemd/logind.conf changed [not included]

-- no debconf information