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Subject: Re: 2.6.15-rc1-mm1 panic in ptrace_check_attach()
From: Badari Pulavarty <pbadari@us.ibm.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: akpm@osdl.org, lkml <linux-kernel@vger.kernel.org>
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	 <20051118180743.GA3708@infradead.org>
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Date: Fri, 18 Nov 2005 10:17:04 -0800
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On Fri, 2005-11-18 at 18:07 +0000, Christoph Hellwig wrote:
> On Fri, Nov 18, 2005 at 09:56:40AM -0800, Badari Pulavarty wrote:
> > Hi Andrew,
> > 
> > I am not sure if its already reported. I get panic in
> > ptrace_check_attach() while trying to run UML on 2.6.15-rc1-mm1.
> > 
> > Going to try 2.6.15-rc1-mm2 now. 
> 
> Looks like 2.6.15-rc1-mm1 has total crap in ptrace_get_task_struct
> (and it looks like my fault because I sent out a wrong patch).
> 
> The patch below should fix it:
> 
> Index: linux-2.6/kernel/ptrace.c
> ===================================================================
> --- linux-2.6.orig/kernel/ptrace.c	2005-11-18 10:25:35.000000000 +0100
> +++ linux-2.6/kernel/ptrace.c	2005-11-18 10:25:54.000000000 +0100
> @@ -459,7 +459,7 @@
>  	read_unlock(&tasklist_lock);
>  	if (!child)
>  		return ERR_PTR(-ESRCH);
> -	return 0;
> +	return child;
>  }
>  
>  #ifndef __ARCH_SYS_PTRACE
> 

Fixed the problem. I guess we need this for 2.6.15-rc1-mm2 also.

Thanks,
Badari