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

Hal Rosenstock halr at voltaire.com
Fri Jun 23 14:22:14 PDT 2006

Hi Doug,

On Fri, 2006-06-23 at 14:44, Doug Ledford wrote:
> 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 

ib_mthca.ko has a number of unresolved symbols which are in the MAD
module (ib_mad.ko) as well as IB core (ib_core.ko) so those are loaded
when mthca is. If you look in /lib/modules/2.6.n/modules.dep, you should
see these dependencies for ib_mthca.

-- Hal

> 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).

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