linux-kernel - Re: [PATCH] USB: Gadget: Composite: Added error handling codes to prevent a memory leak case when the configuration's bind function failed

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Date:	Tue, 20 Mar 2012 14:41:30 +0100
From:	"Michal Nazarewicz" <mina86@...a86.com>
To:	"Felipe Balbi" <balbi@...com>,
	"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
	"Yongsul Oh" <yongsul96.oh@...sung.com>
Cc:	"Michal Nazarewicz" <mnazarewicz@...il.com>,
	"Sergei Shtylyov" <sshtylyov@...sta.com>,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] USB: Gadget: Composite: Added error handling codes to
 prevent a memory leak case when the configuration's bind function failed

On Tue, 20 Mar 2012 02:38:38 +0100, Yongsul Oh <yongsul96.oh@...sung.com> wrote:

>  In some USB composite gadget drivers, the configuration's bind function
>   called by the usb_add_config() calls multiple bind config functions.
>   (for example cdc2 configuration bind function in the cdc_do_config()
>   of the cdc2.c has two functionality bind config functions.
>   - the ecm_bind_config() & the acm_bind_config())
>
>  In each functionality bind config function, new instance is allocated and
>   finally added by the usb_add_function().
>
>  So if an error occurred during the second functionality bind config
>   (for example an error occurred at the acm_bind_config() after succeeding of
>   the ecm_bind_function()), the instance created by the acm_bind_config()
>   cannot be freed creating a memory leak.
>
>  This patch fixes this issue.
>
> Signed-off-by: Yongsul Oh <yongsul96.oh@...sung.com>

Like before:

Acked-by: Michal Nazarewicz <mina86@...a86.com>

> ---
>  drivers/usb/gadget/composite.c |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index baaebf2..4cb1801 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -737,6 +737,19 @@ int usb_add_config(struct usb_composite_dev *cdev,
> 	status = bind(config);
>  	if (status < 0) {
> +		while (!list_empty(&config->functions)) {
> +			struct usb_function		*f;
> +
> +			f = list_first_entry(&config->functions,
> +					struct usb_function, list);
> +			list_del(&f->list);
> +			if (f->unbind) {
> +				DBG(cdev, "unbind function '%s'/%p\n",
> +					f->name, f);
> +				f->unbind(config, f);
> +				/* may free memory for "f" */
> +			}
> +		}
>  		list_del(&config->list);
>  		config->cdev = NULL;
>  	} else {


-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +----<email/xmpp: mpn@...gle.com>--------------ooO--(_)--Ooo--
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