Wei Liu
2013-May-20 11:05 UTC
[PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails
We should correctly free related resources (grant ref, memory page, evtchn)
when setup_netfront fails.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
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
Konrad Rzeszutek Wilk
2013-May-20 19:24 UTC
Re: [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails
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 <wei.liu2@citrix.com> > --- > 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 >
David Miller
2013-May-20 20:43 UTC
Re: [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails
From: Wei Liu <wei.liu2@citrix.com> Date: Mon, 20 May 2013 12:05:12 +0100> We should correctly free related resources (grant ref, memory page, evtchn) > when setup_netfront fails. > > Signed-off-by: Wei Liu <wei.liu2@citrix.com>Applied.