[Pkg-sysvinit-devel] Bug#840356: initscripts: mountkernfs.sh does not mount configfs

[Christophe Vu-Brugier]

Package: initscripts
Version: 2.88dsf-59.8
Severity: normal

Dear Maintainer,

I am working on the targetcli-fb and python-rtslib-fb packages that
rely on configfs and I think there is an issue in the mountkernfs.sh
script that prevents it from mounting the configfs file system.

The mount_filesystems() function in /etc/init.d/mountkernfs.sh
contains the following code to mount the configfs file system under
/sys/kernel/config:

  if [ -d /sys/kernel/config ]
  then
  	domount "$MNTMODE" configfs "" /sys/kernel/config configfs ""
  fi

The problem is that the /sys/kernel/config directory does not exist
when the script is invoked because the configfs kernel module is not
loaded at that time. The /sys/kernel/config directory does not exist
until the configfs module is probed. See:

  http://lxr.free-electrons.com/source/fs/configfs/mount.c#L142

Invoking `modprobe configfs` before testing for /sys/kernel/config
being a directory allows to mount configfs as expected. I am not sure
it is the proper fix though.

There was a similar issue reported for systemd: #800521

  systemd: sys-kernel-config.mount not functional
  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=800521

The fix for this bug was to make the package install a configuration
file in a modules-load.d directory to load the configfs module. I
tried to do the same for sysv, expecting that the configfs module
would be loaded before mountkernfs.sh is run, but it is not the case.

Maybe we could cut the configfs section from mountkernfs.sh and put it
in a separate mountconfigfs.sh init script that would start after kmod?

What do you think?

With best regards,

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, armhf, armel

Kernel: Linux 4.7.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages initscripts depends on:
ii  coreutils       8.25-2
ii  debianutils     4.8
ii  lsb-base        9.20160629
ii  mount           2.28.2-1
ii  sysv-rc         2.88dsf-59.8
ii  sysvinit-utils  2.88dsf-59.8

Versions of packages initscripts recommends:
ii  e2fsprogs  1.43.3-1
ii  psmisc     22.21-2.1+b1

initscripts suggests no packages.

-- no debconf information