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Re: Problem registering interrupt

Subject: Re: Problem registering interrupt
From: Sébastien Taylor <>
Date: Thu, 6 Jan 2005 15:19:44 -0700
In-reply-to: <>
Original-recipient: rfc822;
References: <> <> <>
So the crash is happening because the handler pointer is null in the irq_desc for interrupt 49. Is there something that I was supposed to do to setup that handler before registering my interrupt? This was working fine under 2.4, is it a change in 2.6 or just in the alchemy port specifically?

Thanks for the help and happy new years,

Le 04-12-22, à 03:44, Jan-Benedict Glaw a écrit :

On Wed, 2004-12-22 11:19:06 +0100, moreau francis <> wrote in message <>:

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

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().


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