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Date: Wed, 28 Nov 2012 12:45:15 -0500
From: "Theodore Ts'o" <tytso@mit.edu>
To: Vahram Martirosyan <vmartirosyan@gmail.com>
Cc: Vahram Martirosyan <vmartirosyan@linuxtesting.org>,
        Andreas Dilger <adilger.kernel@dilger.ca>, linux-ext4@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ext4: fixed ext4_calculate_overhead() bug.
Message-ID: <20121128174515.GC24431@thunk.org>
Mail-Followup-To: Theodore Ts'o <tytso@mit.edu>,
	Vahram Martirosyan <vmartirosyan@gmail.com>,
	Vahram Martirosyan <vmartirosyan@linuxtesting.org>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
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On Wed, Nov 21, 2012 at 04:28:21PM -0800, Vahram Martirosyan wrote:
> The memset operation before check brings to a BUG.
> No need to memset the page with zeroes.
> 
> The patch removes the memset call in ext4_calculate_overhead() function.
> 
> Found by the Spruce system in cooperation with the KEDR Framework.
> 
> Signed-off-by: Vahram Martirosyan <vmartirosyan@linuxtesting.org>

Applied, with a slightly rewritten commit description:

    ext4: fixed potential NULL dereference in ext4_calculate_overhead()
    
    The memset operation before check can cause a BUG if the memory
    allocation failed.  Since we are using get_zeroed_age, there is no
    need to use memset anyway.
    
    Found by the Spruce system in cooperation with the KEDR Framework.
    
    Signed-off-by: Vahram Martirosyan <vmartirosyan@linuxtesting.org>
    Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

						- Ted