xen/netback: free already allocated memory on failure in xen_netbk_get_requests

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index bf692df966a9..dcb2d4d3c3ea 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -978,7 +978,7 @@ static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
                 pending_idx = netbk->pending_ring[index];
                 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
                 if (!page)
-                        return NULL;
+                        goto err;
 
                 gop->source.u.ref = txp->gref;
                 gop->source.domid = vif->domid;
@@ -1000,6 +1000,17 @@ static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
         }
 
         return gop;
+err:
+        /* Unwind, freeing all pages and sending error responses. */
+        while (i-- > start) {
+                xen_netbk_idx_release(netbk, frag_get_pending_idx(&frags[i]),
+                                      XEN_NETIF_RSP_ERROR);
+        }
+        /* The head too, if necessary. */
+        if (start)
+                xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+
+        return NULL;
 }
 
 static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,