From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [Xen-devel] [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails Date: Mon, 20 May 2013 15:24:12 -0400 Message-ID: <20130520192412.GA29728@phenom.dumpdata.com> References: <1369047912-31901-1-git-send-email-wei.liu2@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: xen-devel@lists.xen.org, netdev@vger.kernel.org, ian.campbell@citrix.com To: Wei Liu Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:25944 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754154Ab3ETTYY (ORCPT ); Mon, 20 May 2013 15:24:24 -0400 Content-Disposition: inline In-Reply-To: <1369047912-31901-1-git-send-email-wei.liu2@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, May 20, 2013 at 12:05:12PM +0100, Wei Liu wrote: > We should correctly free related resources (grant ref, memory page, evtchn) > when setup_netfront fails. Looks ok to me. > > Signed-off-by: Wei Liu > --- > drivers/net/xen-netfront.c | 33 +++++++++++++++++++++------------ > 1 file changed, 21 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c > index 1db10141..5770e3b 100644 > --- a/drivers/net/xen-netfront.c > +++ b/drivers/net/xen-netfront.c > @@ -1532,40 +1532,49 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info) > FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE); > > err = xenbus_grant_ring(dev, virt_to_mfn(txs)); > - if (err < 0) { > - free_page((unsigned long)txs); > - goto fail; > - } > + if (err < 0) > + goto grant_tx_ring_fail; > > info->tx_ring_ref = err; > rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); > if (!rxs) { > err = -ENOMEM; > xenbus_dev_fatal(dev, err, "allocating rx ring page"); > - goto fail; > + goto alloc_rx_ring_fail; > } > SHARED_RING_INIT(rxs); > FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE); > > err = xenbus_grant_ring(dev, virt_to_mfn(rxs)); > - if (err < 0) { > - free_page((unsigned long)rxs); > - goto fail; > - } > + if (err < 0) > + goto grant_rx_ring_fail; > info->rx_ring_ref = err; > > err = xenbus_alloc_evtchn(dev, &info->evtchn); > if (err) > - goto fail; > + goto alloc_evtchn_fail; > > err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt, > 0, netdev->name, netdev); > if (err < 0) > - goto fail; > + goto bind_fail; > netdev->irq = err; > return 0; > > - fail: > + /* If we fail to setup netfront, it is safe to just revoke access to > + * granted pages because backend is not accessing it at this point. > + */ > +bind_fail: > + xenbus_free_evtchn(dev, info->evtchn); > +alloc_evtchn_fail: > + gnttab_end_foreign_access_ref(info->rx_ring_ref, 0); > +grant_rx_ring_fail: > + free_page((unsigned long)rxs); > +alloc_rx_ring_fail: > + gnttab_end_foreign_access_ref(info->tx_ring_ref, 0); > +grant_tx_ring_fail: > + free_page((unsigned long)txs); > +fail: > return err; > } > > -- > 1.7.10.4 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel >