Index: patchlets/u32/linux-2.6/net/ipv4/netfilter/ipt_u32.c
===================================================================
--- patchlets/u32/linux-2.6/net/ipv4/netfilter/ipt_u32.c	(revision 4547)
+++ patchlets/u32/linux-2.6/net/ipv4/netfilter/ipt_u32.c	(working copy)
@@ -166,8 +166,10 @@
 			case IPT_U32_AT:
 				AttPos += val;
 				pos = number;
-				if (AttPos + pos + 3 > skb->len || AttPos + pos < 0) 
+				if (AttPos + pos + 3 > skb->len || AttPos + pos < 0) {
+					spin_unlock_bh(&u32_lock);
 					return 0;
+				}
 
 				val = (base[AttPos + pos]<<24) 
 				     +(base[AttPos + pos + 1]<<16)