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Message-ID: <4BD7C13D.6060609@gmail.com>
Date:   Tue, 27 Apr 2010 22:01:49 -0700
From:   David Daney <david.s.daney@gmail.com>
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To:     "wilbur.chan" <wilbur512@gmail.com>
CC:     Linux MIPS Mailing List <linux-mips@linux-mips.org>,
        David Daney <ddaney@caviumnetworks.com>
Subject: Re: [octeon]segment without execution priviledge,causing system down.
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On 04/27/2010 06:29 PM, wilbur.chan wrote:
> I'm using a modified kernel version derived from 2.6.21.7,and the cpu
> is octeon cn5860. Strangely I found that , when executing
>
> some instruction in  un-executable segment, the system will hang on,
> together with console  down, and could not response to ping
>
> command.
>    
[...]
> Any one knows why this happened? Thanks
>    

I think I know.

There is a bug in your kernel.  Since execute inhibit support was not 
added to the upstream kernel until very recently, we must assume you got 
your kernel from some vendor.  You could either ask the vendor for a 
fix, or back port it yourself from:

http://www.linux-mips.org/git?p=linux.git;a=commitdiff;h=6dd9344cfc41bcc60a01cdc828cb278be7a10e01

David Daney