Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756173AbZLWQP4 (ORCPT ); Wed, 23 Dec 2009 11:15:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753028AbZLWQPz (ORCPT ); Wed, 23 Dec 2009 11:15:55 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:51490 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752800AbZLWQPy (ORCPT ); Wed, 23 Dec 2009 11:15:54 -0500 From: "Rafael J. Wysocki" To: Alan Stern Subject: Re: [Regression, 2.6.33-rc1->current git] NULL pointer in usb_serial_probe() introduced by the recent kfifo changes Date: Wed, 23 Dec 2009 17:16:40 +0100 User-Agent: KMail/1.12.3 (Linux/2.6.33-rc1-tst; KDE/4.3.3; x86_64; ; ) Cc: Greg KH , linux-usb@vger.kernel.org, LKML , Linus Torvalds , Stefani Seibold , Andrew Morton References: In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200912231716.41004.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2270 Lines: 59 On Wednesday 23 December 2009, Alan Stern wrote: > On Wed, 23 Dec 2009, Rafael J. Wysocki wrote: > > > Hi, > > > > Something like the patch below is necessary to fix a new NULL pointer deref > > in usb_serial_probe() that appeared after the recent kfifo changes (in short, > > the kfifo changes modified the semantics of kfifo_alloc() that > > usb_serial_probe() reiled on). > > > > Thanks, > > Rafael > > > > --- > > drivers/usb/serial/usb-serial.c | 10 +++++++++- > > 1 file changed, 9 insertions(+), 1 deletion(-) > > > > Index: linux-2.6/drivers/usb/serial/usb-serial.c > > =================================================================== > > --- linux-2.6.orig/drivers/usb/serial/usb-serial.c > > +++ linux-2.6/drivers/usb/serial/usb-serial.c > > @@ -595,8 +595,10 @@ static void port_release(struct device * > > usb_free_urb(port->write_urb); > > usb_free_urb(port->interrupt_in_urb); > > usb_free_urb(port->interrupt_out_urb); > > - if (!IS_ERR(port->write_fifo) && port->write_fifo) > > + if (port->write_fifo) { > > kfifo_free(port->write_fifo); > > + kfree(port->write_fifo); > > + } > > kfree(port->bulk_in_buffer); > > kfree(port->bulk_out_buffer); > > kfree(port->interrupt_in_buffer); > > @@ -939,6 +941,12 @@ int usb_serial_probe(struct usb_interfac > > dev_err(&interface->dev, "No free urbs available\n"); > > goto probe_error; > > } > > + port->write_fifo = kzalloc(sizeof(struct kfifo), GFP_KERNEL); > > + if (!port->write_fifo) { > > + dev_err(&interface->dev, > > + "Couldn't allocate write_fifo\n"); > > + goto probe_error; > > + } > > if (kfifo_alloc(port->write_fifo, PAGE_SIZE, GFP_KERNEL)) > > goto probe_error; > > buffer_size = le16_to_cpu(endpoint->wMaxPacketSize); > > Although this would mean further changes elsewhere, doesn't it make > more sense to embed the struct kfifo directly in the usb_serial_port > structure instead of allocating it dynamically? I guess it would, but I wanted to avoid making any further changes. Rafael -- 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/