PREEMPTION vs ndisulator

John Baldwin jhb at
Fri Dec 16 12:10:49 PST 2005

On Friday 16 December 2005 11:34 am, Andrew Gallatin wrote:
> I'm trying to use an ndis driver on an amd64 machine running
> FreeBSD/amd64 -current from yesterday.  If I enable PREEMPTION, the
> machine hangs when loading the driver (kldload never returns):
> ndis0: <Myricom Myri-10G Ethernet Adapter> mem
> 0xfc000000-0xfcffffff,0xfdf00000-0xfdffffff irq 18 at device 0.0 on pci5
> ndis0: NDIS API version: 5.1
> <hang>
> Witness detects no problems, and if I disable PREEMPTION, the driver
> seems to work fine.  Is PREEMPTION not safe to be used with the
> ndisulator, or is there a problem with the ndis driver itself?
> I've included some very brief debugging info below..

Looks like an ithread has preempted your driver's start routine.  If you let 
it run some more and then break into ddb is the same thread (pid 11) still 
running?  Also, which process is pid 11?

John Baldwin <jhb at>  <><
"Power Users Use the Power to Serve"  =

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