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Re: Problem registering interrupt

To: linux-mips@linux-mips.org
Subject: Re: Problem registering interrupt
From: Jan-Benedict Glaw <jbglaw@lug-owl.de>
Date: Wed, 22 Dec 2004 11:44:57 +0100
In-reply-to: <20041222101906.27137.qmail@web25109.mail.ukl.yahoo.com>
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On Wed, 2004-12-22 11:19:06 +0100, moreau francis <francis_moreau2000@yahoo.fr>
wrote in message <20041222101906.27137.qmail@web25109.mail.ukl.yahoo.com>:
> 
> > CPU 0 Unable to handle kernel paging request at
> > virtual address 00000004, epc =4
> 
> Well it suggests me that your driver is trying to 
> access a really nasty pointer: 0x00000004...
> How did you get this address ? From user space ?

Accesses to nearly NULL are normally structure accesses where a pointer
to a given struct was supplied as a NULL pointer.

So an access to 0x00000004 is most probably an access to the second
element of a struct, given/expected that all fields are usually 4-byte
aligned.

>From looking at ./kernel/irq/manage.c:setup_irq(), I guess that you
supply NULL as the "struct irqaction *", which is the 2nd argument of
setup_irq(). It's 2nd structure element is "flags" then... This is the
first thing accessed by the "new" pointer in setup_irq().

MfG, JBG

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