Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751855AbZLWEG5 (ORCPT ); Tue, 22 Dec 2009 23:06:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752627AbZLWEGz (ORCPT ); Tue, 22 Dec 2009 23:06:55 -0500 Received: from netrider.rowland.org ([192.131.102.5]:55359 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751611AbZLWEGy (ORCPT ); Tue, 22 Dec 2009 23:06:54 -0500 Date: Tue, 22 Dec 2009 23:06:54 -0500 (EST) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: "Rafael J. Wysocki" cc: Greg KH , , LKML , Linus Torvalds , Stefani Seibold , Andrew Morton Subject: Re: [Regression, 2.6.33-rc1->current git] NULL pointer in usb_serial_probe() introduced by the recent kfifo changes In-Reply-To: <200912230251.31568.rjw@sisk.pl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2059 Lines: 57 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? Alan Stern -- 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/