linux-ext4 - Re: [PATCH RESEND 8/8] ext4: fix a memory leak of ext4_free

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Message-ID: <20201209192916.GN52960@mit.edu>
Date:   Wed, 9 Dec 2020 14:29:16 -0500
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Chunguang Xu <brookxu.cn@...il.com>
Cc:     adilger.kernel@...ger.ca, linux-ext4@...r.kernel.org
Subject: Re: [PATCH RESEND 8/8] ext4: fix a memory leak of ext4_free_data

On Sat, Nov 07, 2020 at 11:58:18PM +0800, Chunguang Xu wrote:
> From: Chunguang Xu <brookxu@...cent.com>
> 
> When freeing metadata, we will create an ext4_free_data and
> insert it into the pending free list. After the current
> transaction is committed, the object will be freed.
> 
> ext4_mb_free_metadata() will check whether the area to be
> freed overlaps with the pending free list. If true, return
> directly. At this time, ext4_free_data is leaked. Fortunately,
> the probability of this problem is relatively small, maybe we
> should fix this problem.
> 
> Signed-off-by: Chunguang Xu <brookxu@...cent.com>

Thanks, applied.  I added an explanatory note that the leak would only
happen when the file system is corrupted (a block claimed by more than
one inode, with those inodes deleted within a single jbd2 transaction).

    	   	      	     	     	    - Ted