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From: Andrew Morton <akpm@linux-foundation.org>
To: wzt.wzt@gmail.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: Check NULL pointer Dereference in mm/filemap.c
Date: Tue, 27 Jul 2010 16:10:49 -0700	[thread overview]
Message-ID: <20100727161049.eeac8c7c.akpm@linux-foundation.org> (raw)
In-Reply-To: <20100726082542.GA2646@localhost.localdomain>

On Mon, 26 Jul 2010 16:25:42 +0800
wzt.wzt@gmail.com wrote:

> mapping->a_ops->direct_IO() is not checked, if it's a NULL pointer, 
> that will casue an oops. pagecache_write_begin/end is exported to
> other functions, so they need to check null pointer before use them. 
> 

The patch checks a lot more things than ->directIO!

It would be best to not add this overhead if possible.  Did you
actually observe an oops?  If so, please fully describe it.


      reply	other threads:[~2010-07-27 23:10 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-26  8:25 [PATCH] mm: Check NULL pointer Dereference in mm/filemap.c wzt.wzt
2010-07-27 23:10 ` Andrew Morton [this message]

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