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Date: Mon, 14 Mar 2011 14:09:14 -0400
From: Stephen Wilson <wilsons@start.ca>
Subject: Re: [PATCH v2 2.6.38-rc8-tip 7/20]  7: uprobes: store/restore
	original instruction.
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To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>, Linux-mm <linux-mm@kvack.org>, Arnaldo Carvalho de Melo <acme@infradead.org>, Linus Torvalds <torvalds@linux-foundation.org>, Ananth N Mavinakayanahalli <ananth@in.ibm.com>, Christoph Hellwig <hch@infradead.org>, Andi Kleen <andi@firstfloor.org>, Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>, Oleg Nesterov <oleg@redhat.com>, LKML <linux-kernel@vger.kernel.org>, Jim Keniston <jkenisto@linux.vnet.ibm.com>, Roland McGrath <roland@hack.frob.com>, SystemTap <systemtap@sources.redhat.com>, Andrew Morton <akpm@linux-foundation.org>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

On Mon, Mar 14, 2011 at 07:05:22PM +0530, Srikar Dronamraju wrote:
>  static int install_uprobe(struct mm_struct *mm, struct uprobe *uprobe)
>  {
> -	int ret = 0;
> +	struct task_struct *tsk;
> +	int ret = -EINVAL;
>  
> -	/*TODO: install breakpoint */
> -	if (!ret)
> +	get_task_struct(mm->owner);
> +	tsk = mm->owner;
> +	if (!tsk)
> +		return ret;

I think you need to check that tsk != NULL before calling
get_task_struct()...


>  static int remove_uprobe(struct mm_struct *mm, struct uprobe *uprobe)
>  {
> -	int ret = 0;
> +	struct task_struct *tsk;
> +	int ret;
> +
> +	get_task_struct(mm->owner);
> +	tsk = mm->owner;
> +	if (!tsk)
> +		return -EINVAL;

And here as well.

-- 
steve

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