[pvrusb2] Still getting kernel oops on pvrusb2 driver removal

[Mike Isely]

Thanks for the info.  I've been saving all of these messages.  This 
Fri/Sat I should be able to make some headway on the problem.  I will 
also likely be active in IRC over that time if someone wants to chat 
about it.

BTW, the other oops about stack-allocated memory being used for DMA is 
something I do understand.  The driver generates USB transfers through 
several pathways.  It's entirely possible that one or more of these 
paths is using small stack allocated transfer buffers.  This is logic 
that has been this way since at least 2005 - first time I've heard that 
this could be a problem.  Likely it's some kind of new constraint with 
the later kernels.  But if this is the case it's easy to fix so I'm not 
worried about it.

  -Mike


On Thu, 22 Apr 2010, JE Geiger wrote:

> Compiled 2.6.34-rc5 stock kernel.  Non-tainted with nvidia (had not
> built the nvidia driver module at time of testing).
> 
> Did modprobe pvrusb2 and got normal stuff:
> 
> http://www.kd4ab.org/modin1
> 
> 
> Did a rmmod pvrusb2 and got the same oops:
> 
> http://www.kd4ab.org/rmout1
> 
> 
> 
> I saw an oops that I was unable to repeat that talked about Poison
> Overwritten.  It appears that 6b6b6b6b..... is a marker that detects a
> random write to a defined structure and/or memory page.  There were
> also comments about Task Structure being fixed.  These are kernel
> issues.
> 
> 
> 
> The more I read, the more I believe that this oops is due to some
> underlying kernel issue and not the pvrusb2 driver.
> 
> The pvrusb2 driver works fine when loaded.  I just can't unload it
> without generating an oops.
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-- 

Mike Isely
isely @ isely (dot) net
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