[openfabrics-ewg] Stopping Infiniband kernel modules from loading at system boot

[Doug Ledford]

On Fri, 2006-06-23 at 10:14 -0700, Don.Albert at Bull.com wrote:
> 
> Short of uninstalling the OFED-1.0 release,  how can I stop the
> Infiniband related kernel modules from loading at system boot?    
> 
> I am trying to debug a problem with programs hanging in the kernel,
>  so I thought that I would try manually loading the modules one at a
> time to see if I could isolate the problem.  This is on a RHEL4 U3
> system with the 2.6.16 kernel and the OFED-1.0 release installed. 
> 
>  I used "/sbin/chkconfig" to turn off the  "openibd" and "opensmd"
> services in the /etc/rc.d/runlevel files.  I even removed "ifcfg-ib0"
> and "ifcfg-ib1" from the /etc/sysconfig/networking-scriptsdirectory.
>  I don't see any other scripts that would cause these modules to be
> loaded.   But every time I reboot, I get the following modules loaded,
> according to /sbin/lsmod: 
> 
> ib_mthca              117424  0 
> ib_mad                 35896  1 ib_mthca 
> ib_core                45952  2 ib_mthca,ib_mad 
> 
> What have I missed? 

/etc/rc.d/rc.sysinit

In the sysinit we load all the modules required to support the hardware
in the system (that's when it prints the Initializing hardware: storage
network sound other [OK] message).  In order to stop that you have to
move the modules out of the way.  But, I'm a bit surprised that ib_mad
is loaded as that doesn't seem a hard dependancy for ib_mthca (or more
appropriately, I'm surprised to see ib_mad and not a bunch of other ib
modules as well, check the /etc/modprobe.conf
and /etc/modprobe.conf.dist to see if there are rules to force lots of
ib modules to be loaded any time ib_core is loaded).

-- 
Doug Ledford <dledford at redhat.com>
http://people.redhat.com/dledford

Infiniband specific RPMs available at
http://people.redhat.com/dledford/Infiniband