Summary: Re: What is this panic?

[Jonathan Eisenhamer]

To All Spots,

	A while ago, I asked:
> 
> To All Spots,
> 
> 	Yes, here is another "what is that panic" question:
> What is the panic:
> 
> 	panic: dup biodone
> 
> The system then reboots.  Any help would be appreciated and all answers
> will be summarized to the net.
> 

As promised, this is the basic answer: For DMA operations, there is a flag
called B_DONE associated with the memory used for the I/O.  When an DMA
I/O operation is complete, the software that initiated the DMA operation
(usually a driver) calls a routine biodone() that among other things, sets
the B_DONE flag.  If, for whatever reason, the B_DONE flag has already
been set, the above panic occurs.  Almost assuredly this is an indication
of a software problem in the driver.

For us, this was directly associated with the installation of new
equipment and the associated drivers.  The problem is now in the process
of being repaired.

Thanks again to all those who replied!!!

Jonathan Eisenhamer
jon at astro.ucla.edu
jon at uclastro.bitnet
bonnie::jon (span 5.708)
(213)206-8596