[linux-dvb] Re: OOPS with budget card + cam (in dvb_ca_en50221_io_write)

[Andrew de Quincey <adq_dvb@lidskialf.net>]

On Saturday 13 Nov 2004 17:01, Johannes Stezenbach wrote:
> Andrew de Quincey wrote:
> > This stack trace is weird! Why is it listing the kernel ip stack's NAT
> > code in it?
>
> If you compile you kernel with CONFIG_FRAME_POINTER (in the "kernel
> hacking" menu) you will get nicer traces. W/o frame pointer stack traces
> are just guesswork.

Ah ok, thanks, I didn't realise you needed frame pointer on as well. Carlo, 
can you do this so the next time it happens I can get a better idea of whats 
going on please?

I've found the reason for Kenneth's crashes - in the process of fixing them.

Oh - an issue with dvb_generic_open()/ dvb_generic_release(). They don't 
increment the module usage counters, so it is possible to unload a module 
while a userspace process still has it open.  The problem being of course, 
dvb_generic_open() resides in dvb-core.ko - so if it were to increment the 
usage counter, it would be doing it to the wrong module.

Is there some wrinkle I've missed with how you are meant to implement your 
fops structure? Or is this just a general problem?