linux-kernel - Re: [PATCH] drbd: add module_put() on error path in drbd_proc

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Message-ID: <9738633.yZ4agRkgQF@quad>
Date:	Mon, 04 Mar 2013 21:31:09 +0100
From:	Philipp Reisner <philipp.reisner@...bit.com>
To:	Alexey Khoroshilov <khoroshilov@...ras.ru>
Cc:	Lars Ellenberg <drbd-dev@...ts.linbit.com>,
	drbd-user@...ts.linbit.com, linux-kernel@...r.kernel.org,
	ldv-project@...uxtesting.org
Subject: Re: [PATCH] drbd: add module_put() on error path in drbd_proc_open()

Hi Alexey,

Thanks a lot! I have put it into our tree.
http://git.drbd.org/gitweb.cgi?p=drbd-8.4.git

I intend to get it into the 3.10 merge window.

Best,
 Phil

> If single_open() fails in drbd_proc_open(), module refcount is left
> incremented. The patch adds module_put() on the error path.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Alexey Khoroshilov <khoroshilov@...ras.ru>
> ---
>  drivers/block/drbd/drbd_proc.c |   10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
> index 56672a6..30fe0a5 100644
> --- a/drivers/block/drbd/drbd_proc.c
> +++ b/drivers/block/drbd/drbd_proc.c
> @@ -313,8 +313,14 @@ static int drbd_seq_show(struct seq_file *seq, void *v)
> 
>  static int drbd_proc_open(struct inode *inode, struct file *file)
>  {
> -	if (try_module_get(THIS_MODULE))
> -		return single_open(file, drbd_seq_show, PDE(inode)->data);
> +	int err;
> +
> +	if (try_module_get(THIS_MODULE)) {
> +		err = single_open(file, drbd_seq_show, PDE(inode)->data);
> +		if (err)
> +			module_put(THIS_MODULE);
> +		return err;
> +	}
>  	return -ENODEV;
>  }
--
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