Staging: batman-adv: avoid crash on memory allocation error

skb_share_check() returns NULL if it can't allocate more memory but
it still frees the skbuff.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 9 insertions, 7 deletions

diff --git a/drivers/staging/batman-adv/hard-interface.c b/drivers/staging/batman-adv/hard-interface.c
index f8b1ba3910ad..0f94158b2660 100644
--- a/drivers/staging/batman-adv/hard-interface.c
+++ b/drivers/staging/batman-adv/hard-interface.c
@@ -426,10 +426,11 @@ int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
         struct net_device_stats *stats;
         int ret;
 
-    skb = skb_share_check(skb, GFP_ATOMIC);
+        skb = skb_share_check(skb, GFP_ATOMIC);
 
-    if (skb == NULL)
-                goto err_free;
+        /* skb was released by skb_share_check() */
+        if (!skb)
+                goto err_out;
 
         /* packet should hold at least type and version */
         if (unlikely(skb_headlen(skb) < 2))
@@ -444,7 +445,7 @@ int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
         if (!batman_if)
                 goto err_free;
 
-    stats = (struct net_device_stats *) dev_get_stats(skb->dev);
+        stats = (struct net_device_stats *)dev_get_stats(skb->dev);
         if (stats) {
                 stats->rx_packets++;
                 stats->rx_bytes += skb->len;
@@ -490,6 +491,7 @@ int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
         default:
                 ret = NET_RX_DROP;
         }
+
         if (ret == NET_RX_DROP)
                 kfree_skb(skb);
 
@@ -500,9 +502,9 @@ int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
         return NET_RX_SUCCESS;
 
 err_free:
-    kfree_skb(skb);
-    return NET_RX_DROP;
-
+        kfree_skb(skb);
+err_out:
+        return NET_RX_DROP;
 }