Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754485Ab1C1OGd (ORCPT ); Mon, 28 Mar 2011 10:06:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15436 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754336Ab1C1OGb (ORCPT ); Mon, 28 Mar 2011 10:06:31 -0400 Subject: [GIT PATCH] Fix memory leak in qcserial driver From: Steven Hardy To: gregkh@suse.de, mjg@redhat.com Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Date: Mon, 28 Mar 2011 15:06:26 +0100 Message-ID: <1301321186.4397.13.camel@shardy.csb> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4642 Lines: 127 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: 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() 2 - Ensure that the serial->private data is freed in the event of the probe failing and returning -ENODEV. This error-path leak is less likely but still possible, it was discussed previously but not actually fixed AFAICS: http://kerneltrap.org/mailarchive/linux-kernel/2010/6/14/4582980/thread, http://lkml.org/lkml/2010/6/20/234 3 - Don't assign serial->private when doing the kzalloc or serial->private ends up pointing to freed memory in the event we return -ENODEV, instead call usb_set_serial_data(serial, data) at the end of the function, and only have one return. Please keep me on CC for any responses or review comments, since I'm not currently subscribed to LKML Signed-off-by: Steve Hardy diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c index 8858201..e66530a 100644 --- a/drivers/usb/serial/qcserial.c +++ b/drivers/usb/serial/qcserial.c @@ -111,7 +111,7 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id) ifnum = intf->desc.bInterfaceNumber; dbg("This Interface = %d", ifnum); - data = serial->private = kzalloc(sizeof(struct usb_wwan_intf_private), + data = kzalloc(sizeof(struct usb_wwan_intf_private), GFP_KERNEL); if (!data) return -ENOMEM; @@ -134,8 +134,10 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id) usb_endpoint_is_bulk_out(&intf->endpoint[1].desc)) { dbg("QDL port found"); - if (serial->interface->num_altsetting == 1) - return 0; + if (serial->interface->num_altsetting == 1) { + retval = 0; /* Success */ + break; + } retval = usb_set_interface(serial->dev, ifnum, 1); if (retval < 0) { @@ -145,7 +147,6 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id) retval = -ENODEV; kfree(data); } - return retval; } break; @@ -166,6 +167,7 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id) "Could not set interface, error %d\n", retval); retval = -ENODEV; + kfree(data); } } else if (ifnum == 2) { dbg("Modem port found"); @@ -177,7 +179,6 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id) retval = -ENODEV; kfree(data); } - return retval; } else if (ifnum==3) { /* * NMEA (serial line 9600 8N1) @@ -191,6 +192,7 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id) "Could not set interface, error %d\n", retval); retval = -ENODEV; + kfree(data); } } break; @@ -198,13 +200,27 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id) default: dev_err(&serial->dev->dev, "unknown number of interfaces: %d\n", nintf); + retval = -ENODEV; kfree(data); - return -ENODEV; } + /* Set serial->private may be null if -ENODEV */ + usb_set_serial_data(serial, data); 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 +238,7 @@ 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, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/