goto drop_unlock;
                }
 
-               if (x->props.replay_window && x->repl->check(x, skb, seq)) {
+               if (x->repl->check(x, skb, seq)) {
                        XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
                        goto drop_unlock;
                }
 
        u32 diff;
        u32 seq = ntohl(net_seq);
 
+       if (!x->props.replay_window)
+               return 0;
+
        if (unlikely(seq == 0))
                goto err;
 
 {
        unsigned int bitnr, nr;
        struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
+       u32 pos;
        u32 seq = ntohl(net_seq);
        u32 diff =  replay_esn->seq - seq;
-       u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
+
+       if (!replay_esn->replay_window)
+               return 0;
+
+       pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 
        if (unlikely(seq == 0))
                goto err;
        unsigned int bitnr, nr;
        u32 diff;
        struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
+       u32 pos;
        u32 seq = ntohl(net_seq);
-       u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
        u32 wsize = replay_esn->replay_window;
        u32 top = replay_esn->seq;
        u32 bottom = top - wsize + 1;
 
+       if (!wsize)
+               return 0;
+
+       pos = (replay_esn->seq - 1) % replay_esn->replay_window;
+
        if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
                     (replay_esn->seq < replay_esn->replay_window - 1)))
                goto err;