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Message-ID: <op.wa9f6nz03l0zgt@mpn-glaptop>
Date: Fri, 16 Mar 2012 12:14:37 +0100
From: "Michal Nazarewicz" <mina86@...a86.com>
To: "Felipe Balbi" <balbi@...com>,
"Yongsul Oh" <yongsul96.oh@...sung.com>
Cc: "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
"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 Fri, 16 Mar 2012 07:27:15 +0100, Yongsul Oh <yongsul96.oh@...sung.com> wrote:
> In some usb gadget driver, (for example usb gadget serial driver(serial.c),
s/usb/USB/g
s/gadget driver/composite gadget drivers/
I also don't think the list of examples is necessary here. Maybe just a list file
names? My personal opinion, others may disagree though.
Also, comma should go after the closing paren.
> multifunction composite driver(multi,c), nokia composite gadget driver(nokia.c),
> HID composite driver(hid.c), CDC composite driver(cdc2.c)..) the configuration's
> bind function by called the 'usb_add_config()' has multiple bind config functions
s/by called the/called by the/
s/has/calls/
> for each functionality. (for example cdc2 configuration bind function -'cdc_do_config()'
s/functions for each functionality/functions, one for each USB functionality/
> has two functionality bind config functions -'ecm_bind_config()' & 'acm_bind_config()'
> in CDC composite driver.)
>
> In each functionality bind config function, new instance for each functionality is
s/for each functionality//
> allocated & initialized by 'kzalloc()' and finally the new instance is added by
s/& initialized by 'kzalloc()' and finally the new instance/and/
> 'usb_add_function()'. After 'usb_add_function' state, already created the instance
> is only handled by it's configuration & freed from functionality unbind function.
I'm not sure what you meant by this last sentence.
> So, If an error occurred during the second functionality bind config state,
s/If/if/
s/state//
> (for example an error occurred at 'acm_bind_config()' after succeeding of
> 'ecm_bind_function()') the created instance by 'acm_bind_config()'
s/the created instance by 'acm_bind_config()'/the instance created by acm_bind_config()/
> cannot be freed. And it makes memory leak situation.
s/freed. And it makes memory leak situation./freed creating a memory leak./
> This patch fixes this issue
s/issue/issue./
Also, drop apostrophes around function names. It looks weird.
> Signed-off-by: Yongsul Oh <yongsul96.oh@...sung.com>
Acked-by: Michal Nazarewicz <mina86@...a86.com>
Also, like written previously, I think there might be memory leak in other error
recovery paths as well. If you could take a look whether I'm right, that would be
awesome.
> ---
> 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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