From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCHv1] xen-netfront: properly destroy queues when removing device Date: Wed, 27 May 2015 11:20:58 -0400 Message-ID: <5565E0DA.9070309@oracle.com> References: <1432737970-31872-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: xen-devel@lists.xenproject.org, Konrad Rzeszutek Wilk To: David Vrabel , netdev@vger.kernel.org Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:32456 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751359AbbE0PVE (ORCPT ); Wed, 27 May 2015 11:21:04 -0400 In-Reply-To: <1432737970-31872-1-git-send-email-david.vrabel@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: On 05/27/2015 10:46 AM, David Vrabel wrote: > xennet_remove() freed the queues before freeing the netdevice which > results in a use-after-free when free_netdev() tries to delete the > napi instances that have already been freed. > > Fix this by fully destroy the queues (which includes deleting the napi > instances) before freeing the netdevice. > > Signed-off-by: David Vrabel Reviewed-by: Boris Ostrovsky > --- > drivers/net/xen-netfront.c | 15 ++------------- > 1 file changed, 2 insertions(+), 13 deletions(-) > > diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c > index 3f45afd..e031c94 100644 > --- a/drivers/net/xen-netfront.c > +++ b/drivers/net/xen-netfront.c > @@ -1698,6 +1698,7 @@ static void xennet_destroy_queues(struct netfront_info *info) > > if (netif_running(info->netdev)) > napi_disable(&queue->napi); > + del_timer_sync(&queue->rx_refill_timer); > netif_napi_del(&queue->napi); > } > > @@ -2102,9 +2103,6 @@ static const struct attribute_group xennet_dev_group = { > static int xennet_remove(struct xenbus_device *dev) > { > struct netfront_info *info = dev_get_drvdata(&dev->dev); > - unsigned int num_queues = info->netdev->real_num_tx_queues; > - struct netfront_queue *queue = NULL; > - unsigned int i = 0; > > dev_dbg(&dev->dev, "%s\n", dev->nodename); > > @@ -2112,16 +2110,7 @@ static int xennet_remove(struct xenbus_device *dev) > > unregister_netdev(info->netdev); > > - for (i = 0; i < num_queues; ++i) { > - queue = &info->queues[i]; > - del_timer_sync(&queue->rx_refill_timer); > - } > - > - if (num_queues) { > - kfree(info->queues); > - info->queues = NULL; > - } > - > + xennet_destroy_queues(info); > xennet_free_netdev(info->netdev); > > return 0;