[GIT PATCH 1/3] Resend : Fix memory leak in qcserial driver

Steven Hardy
2011-03-28T17:33:51Z

On Mon, Mar 28, 2011 at 07:21:48AM -0700, Greg KH wrote:
> On Mon, Mar 28, 2011 at 03:06:26PM +0100, Steven Hardy wrote:
> > Hi,
> >
> > I've been experimenting with kmemleak and noticed a recurring leak warning whenever I load & unload the qcserial driver.
> >
> > Inspection of the code seems to indicate the leak is the serial->private data allocated in the qcprobe() function,
> > which is never freed (apart from in some of the qcprobe error paths) as far as I can tell.
> >
> > The patch below fixes the following problems:
>
> <snip>
>
> Can you fix your email client to properly wrap your lines?

Apologies, was trying to avoid mangling the patch & ended up mangling the preamble instead, back to mutt now which will hopefully do the right thing! :)

> Also, as you do 3 different things here, can you break this into 3
> patches and resend them?

Done, please find patch 1 of 3 below:

The patch below fixes the following problem:
1 - Always free the serial->private data allocated in qcprobe, added a new function qc_release which frees the memory rather than relying on the usb_wwan_release function which does not. Without this cleanup, we leak the memory allocated in qcprobe when the kfree(serial) happens in usb-serial.c::destroy_serial()

Please keep me on CC for any responses or review comments, since I'm not currently subscribed to LKML

Signed-off-by: Steve Hardy <shardy@redhat.com>

diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c
index 8858201..6e3b933 100644
--- a/drivers/usb/serial/qcserial.c
+++ b/drivers/usb/serial/qcserial.c
@@ -205,6 +205,18 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
return retval;
}

+static void qc_release(struct usb_serial *serial)
+{
+ struct usb_wwan_intf_private *priv = usb_get_serial_data(serial);
+
+ dbg("%s", __func__);
+
+ /* Call usb_wwan release & free the private data allocated in qcprobe */
+ usb_wwan_release(serial);
+ usb_set_serial_data(serial, NULL);
+ kfree(priv);
+}
+
static struct usb_serial_driver qcdevice = {
.driver = {
.owner = THIS_MODULE,
@@ -222,7 +234,7 @@ static struct usb_serial_driver qcdevice = {
.chars_in_buffer = usb_wwan_chars_in_buffer,
.attach = usb_wwan_startup,
.disconnect = usb_wwan_disconnect,
- .release = usb_wwan_release,
+ .release = qc_release,
#ifdef CONFIG_PM
.suspend = usb_wwan_suspend,
.resume = usb_wwan_resume,