From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932342AbdD0IoR (ORCPT ); Thu, 27 Apr 2017 04:44:17 -0400 Received: from mail-lf0-f65.google.com ([209.85.215.65]:36513 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751958AbdD0IoK (ORCPT ); Thu, 27 Apr 2017 04:44:10 -0400 Date: Thu, 27 Apr 2017 10:44:01 +0200 From: Johan Hovold To: Andreas Kemnade Cc: davem@davemloft.net, joe@perches.com, gregkh@linuxfoundation.org, peter@hurleysoftware.com, hns@goldelico.com, linux-usb@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: hso: register netdev later to avoid a race condition Message-ID: <20170427084401.GP2823@localhost> References: <1493227600-10102-1-git-send-email-andreas@kemnade.info> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1493227600-10102-1-git-send-email-andreas@kemnade.info> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 26, 2017 at 07:26:40PM +0200, Andreas Kemnade wrote: > If the netdev is accessed before the urbs are initialized, > there will be NULL pointer dereferences. That is avoided by > registering it when it is fully initialized. > Reported-by: H. Nikolaus Schaller > Signed-off-by: Andreas Kemnade > --- > drivers/net/usb/hso.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c > index 93411a3..00067a0 100644 > --- a/drivers/net/usb/hso.c > +++ b/drivers/net/usb/hso.c > @@ -2534,13 +2534,6 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface, > SET_NETDEV_DEV(net, &interface->dev); > SET_NETDEV_DEVTYPE(net, &hso_type); > > - /* registering our net device */ > - result = register_netdev(net); > - if (result) { > - dev_err(&interface->dev, "Failed to register device\n"); > - goto exit; > - } > - > /* start allocating */ > for (i = 0; i < MUX_BULK_RX_BUF_COUNT; i++) { > hso_net->mux_bulk_rx_urb_pool[i] = usb_alloc_urb(0, GFP_KERNEL); > @@ -2560,6 +2553,13 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface, > > add_net_device(hso_dev); > > + /* registering our net device */ > + result = register_netdev(net); > + if (result) { > + dev_err(&interface->dev, "Failed to register device\n"); > + goto exit; This all looks good, but you should consider cleaning up the error handling of this function as a follow-up as we should not be deregistering netdevs that have never been registered (e.g. if a required endpoint is missing or if registration fails for some reason). But just to be clear, this problem existed also before this change. > + } > + > hso_log_port(hso_dev); > > hso_create_rfkill(hso_dev, interface); Reviewed-by: Johan Hovold Thanks, Johan