linux-kernel - Re: [PATCH] proc: add proc_seq

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Message-ID: <20180611062354.GA32641@lst.de>
Date:   Mon, 11 Jun 2018 08:23:54 +0200
From:   Christoph Hellwig <hch@....de>
To:     Chunyu Hu <chuhu@...hat.com>
Cc:     viro@...iv.linux.org.uk, hch@....de, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] proc: add proc_seq_release

On Sun, Jun 10, 2018 at 03:51:24AM +0800, Chunyu Hu wrote:
> kmemleak reported some memory leak on reading proc files. After adding
> some debug lines, find that proc_seq_fops is using seq_release as
> release handler, which won't handle the free of 'private' field of
> seq_file, while in fact the open handler proc_seq_open could create
> the private data with __seq_open_private when state_size is greater
> than zero. So after reading files created with proc_create_seq_private,
> such as /proc/timer_list and /proc/vmallocinfo, the private mem of a
> seq_file is not freed. Fix it by adding the paired proc_seq_release
> as the default release handler of proc_seq_ops instead of seq_release.

Indeed, thanks for the patch.

Reviewed-by: Christoph Hellwig <hch@....de>