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Date: Tue, 04 Sep 2012 16:10:22 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai] kernel NULL pointer dereference
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To: Henri Roosen <henriroosen@gmail.com>
Cc: Xenomai <xenomai@xenomai.org>

On 09/04/2012 03:42 PM, Henri Roosen wrote:
> Hi,
> 
> I'm using the bleeding edge of Xenomai (0590cb45adce468f619) and Ipipe
> (d21e8cdbdcf21ade) on a x86 multicore system and kernel 3.4.6.
> I reserved one cpu (kernel param isolcpus=1).
> 
> Our application triggers the following NULL pointer dereference when I
> set the affinity of some tasks to cpu 0 and other tasks to cpu 1.
> The application does not trigger this when all tasks have the same
> affinity (set via /proc/xenomai/affinity).
> 
> I was able to reproduce this also under QEMU and will do some
> debugging, but maybe someone knows what is wrong already by seeing the
> stacktrace below:

Could you try to reduce the bug to a simple testcase which we would try
and run to reproduce?

> [  108.013023] BUG: unable to handle kernel NULL pointer dereference
at 00000294
> [  108.013550] IP: [<c0126a91>] __lock_task_sighand+0x53/0xc3

Or send us a disassembly of the function __lock_task_sighand?

-- 
					    Gilles.