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Date: Thu, 14 Feb 2008 16:42:16 -0800
From: Arjan van de Ven <arjan@linux.intel.com>
To: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] latencytop: fix kernel panic and memory leak on proc
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On Thu, 14 Feb 2008 14:51:19 -0800
Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> wrote:

> Hi,
> 
> I posted 2 patches to fix kernel panic and memory leak.
> http://lkml.org/lkml/2008/2/14/282
> http://lkml.org/lkml/2008/2/14/283
> 
> But, I think this patch is better than old ones.
> 
> ---
> From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
> 
> Reading /proc/<pid>/latency or /proc/<pid>/task/<tid>/latency could
> cause NULL pointer dereference.
> 
> In lstats_open(), get_proc_task() can return NULL, in which case the
> kernel will oops at lstats_show_proc() because m->private is NULL.
> 
> This can be reproduced by the follwoing script.
> while :
> do
> 	bash -c 'ls > ls.$$' &
> 	pid=$!
> 	cat /proc/$pid/latency &
> 	cat /proc/$pid/latency &
> 	cat /proc/$pid/latency &
> 	cat /proc/$pid/latency
> done
> 
> And the task struct which gotten by get_proc_task() is never put.
> put_task_struct() should be called.
> 
> This patch changes the private is used to store inode, and the task
> struct will be gotten and putted in read or write function.
> 
> Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>


Fine with me; Ingo please merge
Thanks for working on this!

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