service target can not start or stop

[ExecDevOps]

OS: CentOS 6.7
Kernel: 4.1.7-1.el6.elrepo.x86_64
targetcli: 3.0.pre4.3 (latest as of 2015-09-22)

The service "target" can not re-start or stop, failing with the following error messages:

Failed to unload target core module target_core_mod
Could not stop The Linux SCSI Target

The cause of the problem is that the module target_core_user does not get unloaded whenever the target service stops and the module target_core_mod seems to depend on it. (The modules come with the kernel and are located at /lib/modules/4.1.7-1.el6.elrepo.x86_64/kernel/drivers/target)

The problem and the solution is within the init script /etc/rc.d/init.d/target at the definition of the target core modules:

CORE_MODS="target_core_mod target_core_pscsi target_core_iblock target_core_file"

Adding target_core_user to the list of modules to load / unload when the target service starts / stops solves the problem:

CORE_MODS="target_core_mod target_core_user target_core_pscsi target_core_iblock target_core_file"

I think that the ordering of the modules in the list is important, target_core_user has to be unloaded before target_core_mod when the target service stops.

[rickysarraf]

On Debian, the same issue was seen. I've fixed the same with extending the list of modules and using modprobe instead.

[fukunagt]

Thank you for the valuable information. I have faced the same issue on Ubuntu 16.04. And I have added the following line and fixed the issue! Thank you so much!

/etc/init.d/target
CORE_MODS="target_core_mod target_core_user target_core_pscsi target_core_iblock target_core_file