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From: Jan-Benedict Glaw <jbglaw@lug-owl.de>
To: linux-mips@linux-mips.org
Subject: Re: Problem registering interrupt
Date: Wed, 22 Dec 2004 11:44:57 +0100	[thread overview]
Message-ID: <20041222104457.GR2460@lug-owl.de> (raw)
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

-- 
Jan-Benedict Glaw       jbglaw@lug-owl.de    . +49-172-7608481             _ O _
"Eine Freie Meinung in  einem Freien Kopf    | Gegen Zensur | Gegen Krieg  _ _ O
 fuer einen Freien Staat voll Freier Bürger" | im Internet! |   im Irak!   O O O
ret = do_actions((curr | FREE_SPEECH) & ~(NEW_COPYRIGHT_LAW | DRM | TCPA));

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WARNING: multiple messages have this Message-ID (diff)
From: Jan-Benedict Glaw <jbglaw@lug-owl.de>
To: linux-mips@linux-mips.org
Subject: Re: Problem registering interrupt
Date: Wed, 22 Dec 2004 11:44:57 +0100	[thread overview]
Message-ID: <20041222104457.GR2460@lug-owl.de> (raw)
Message-ID: <20041222104457.7TtM9Mz0t-Yje3MUhqikIqIsxm_PX5z-FidNq9BNk1I@z> (raw)
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

-- 
Jan-Benedict Glaw       jbglaw@lug-owl.de    . +49-172-7608481             _ O _
"Eine Freie Meinung in  einem Freien Kopf    | Gegen Zensur | Gegen Krieg  _ _ O
 fuer einen Freien Staat voll Freier Bürger" | im Internet! |   im Irak!   O O O
ret = do_actions((curr | FREE_SPEECH) & ~(NEW_COPYRIGHT_LAW | DRM | TCPA));

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  reply	other threads:[~2004-12-22 10:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <41C947CC.20709@innova-card.com>
2004-12-22 10:19 ` Problem registering interrupt moreau francis
2004-12-22 10:44   ` Jan-Benedict Glaw [this message]
2004-12-22 10:44     ` Jan-Benedict Glaw
2005-01-06 22:19     ` Sébastien Taylor
2004-12-21 17:55 Sébastien Taylor

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