* [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails
@ 2013-05-20 11:05 Wei Liu
2013-05-20 19:24 ` [Xen-devel] " Konrad Rzeszutek Wilk
2013-05-20 20:43 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Wei Liu @ 2013-05-20 11:05 UTC (permalink / raw)
To: xen-devel, netdev; +Cc: ian.campbell, Wei Liu
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
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Xen-devel] [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails
2013-05-20 11:05 [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails Wei Liu
@ 2013-05-20 19:24 ` Konrad Rzeszutek Wilk
2013-05-20 20:43 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-05-20 19:24 UTC (permalink / raw)
To: Wei Liu; +Cc: xen-devel, netdev, ian.campbell
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
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails
2013-05-20 11:05 [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails Wei Liu
2013-05-20 19:24 ` [Xen-devel] " Konrad Rzeszutek Wilk
@ 2013-05-20 20:43 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2013-05-20 20:43 UTC (permalink / raw)
To: wei.liu2; +Cc: xen-devel, netdev, ian.campbell
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.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-05-20 20:43 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-05-20 11:05 [PATCH net-next V2] xen-netfront: avoid leaking resources when setup_netfront fails Wei Liu
2013-05-20 19:24 ` [Xen-devel] " Konrad Rzeszutek Wilk
2013-05-20 20:43 ` David Miller
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).