[Bug 1866392] [NEW] [bionic] dlm_controld won't start due to missing device files

[Rafael David Tinoco]

Public bug reported:

Right after installing dlm and dlm_controld, when trying to start the
service, you will face:

rafaeldtinoco at clubionic01:~$ systemctl status dlm.service
● dlm.service - dlm control daemon
   Loaded: loaded (/lib/systemd/system/dlm.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Fri 2020-03-06 19:13:32 UTC; 35s ago
     Docs: man:dlm_controld
           man:dlm.conf
           man:dlm_stonith
  Process: 31644 ExecStart=/usr/sbin/dlm_controld --foreground $DLM_CONTROLD_OPTS (code=exited, status=1/FAILURE)
  Process: 31643 ExecStartPre=/sbin/modprobe dlm (code=exited, status=0/SUCCESS)
 Main PID: 31644 (code=exited, status=1/FAILURE)

Mar 06 19:13:21 clubionic01 systemd[1]: Starting dlm control daemon...
Mar 06 19:13:21 clubionic01 dlm_controld[31644]: 8746 dlm_controld 4.0.7 started
Mar 06 19:13:32 clubionic01 dlm_controld[31644]: 8756 cannot find device /dev/misc/dlm-control with minor 56
Mar 06 19:13:32 clubionic01 systemd[1]: dlm.service: Main process exited, code=exited, status=1/FAILURE
Mar 06 19:13:32 clubionic01 systemd[1]: dlm.service: Failed with result 'exit-code'.
Mar 06 19:13:32 clubionic01 systemd[1]: Failed to start dlm control daemon.

This happens even after the module "dlm" was loaded (as you can see in
the ExecStartPre= line).

(k)rafaeldtinoco at clubionic01:~$ ls -lah /dev/dlm*
crw------- 1 root root 10, 56 Mar  6 19:08 /dev/dlm-control
crw------- 1 root root 10, 55 Mar  6 19:08 /dev/dlm-monitor
crw------- 1 root root 10, 54 Mar  6 19:08 /dev/dlm_plock

And we can see hardcoded device filename paths:

dlm_controld/action.c:          rv = find_udev_device("/dev/misc/dlm-control", control_minor);
dlm_controld/action.c:          rv = find_udev_device("/dev/misc/dlm-monitor", monitor_minor);
dlm_controld/action.c:          rv = find_udev_device("/dev/misc/dlm_plock", plock_minor);

And the way rules.d files are generated:

rafaeldtinoco at workstation:~/.../dlm$ grep -r UDEVDIR *
libdlm/Makefile:UDEVDIR=/usr/lib/udev/rules.d
libdlm/Makefile:        $(INSTALL) -d $(DESTDIR)/$(UDEVDIR)
libdlm/Makefile:        $(INSTALL) -m 644 $(UDEV_TARGET) $(DESTDIR)/$(UDEVDIR)

And that the package contains those:

(k)rafaeldtinoco at clubionic01:~$ cat /lib/udev/rules.d/51-dlm.rules
KERNEL=="dlm-control", MODE="0666", SYMLINK+="misc/dlm-control"
KERNEL=="dlm-monitor", MODE="0666", SYMLINK+="misc/dlm-monitor"
KERNEL=="dlm_plock", MODE="0666", SYMLINK+="misc/dlm_plock"
KERNEL=="dlm_*", MODE="0660", SYMLINK+="misc/%k"

** Affects: dlm (Ubuntu)
     Importance: Undecided
         Status: Triaged

** Affects: dlm (Ubuntu Bionic)
     Importance: Medium
     Assignee: Rafael David Tinoco (rafaeldtinoco)
         Status: Confirmed

** Changed in: dlm (Ubuntu)
       Status: New => Confirmed

** Changed in: dlm (Ubuntu)
       Status: Confirmed => Triaged

** Also affects: dlm (Ubuntu Bionic)
   Importance: Undecided
       Status: New

** Changed in: dlm (Ubuntu Bionic)
   Importance: Undecided => Medium

** Changed in: dlm (Ubuntu Bionic)
     Assignee: (unassigned) => Rafael David Tinoco (rafaeldtinoco)

** Changed in: dlm (Ubuntu Bionic)
       Status: New => Confirmed

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https://bugs.launchpad.net/bugs/1866392

Title:
  [bionic] dlm_controld won't start due to missing device files

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