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Date: Mon, 14 Mar 2011 18:10:00 -0000
From: Stephen Wilson <wilsons@start.ca>
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>
Subject: Re: [PATCH v2 2.6.38-rc8-tip 7/20]  7: uprobes: store/restore	original instruction.
Message-ID: <20110314180914.GA18855@fibrous.localdomain>
References: <20110314133403.27435.7901.sendpatchset@localhost6.localdomain6> <20110314133522.27435.45121.sendpatchset@localhost6.localdomain6>
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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