1 files changed, 15 insertions, 8 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 53c8ce4046b2..b5e315f13641 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1403,8 +1403,16 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 
         BUG_ON(!pcount);
 
-        /* Adjust hint for FACK. Non-FACK is handled in tcp_sacktag_one(). */
-        if (tcp_is_fack(tp) && (skb == tp->lost_skb_hint))
+        /* Adjust counters and hints for the newly sacked sequence
+         * range but discard the return value since prev is already
+         * marked. We must tag the range first because the seq
+         * advancement below implicitly advances
+         * tcp_highest_sack_seq() when skb is highest_sack.
+         */
+        tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
+                        start_seq, end_seq, dup_sack, pcount);
+
+        if (skb == tp->lost_skb_hint)
                 tp->lost_cnt_hint += pcount;
 
         TCP_SKB_CB(prev)->end_seq += shifted;
@@ -1430,12 +1438,6 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
                 skb_shinfo(skb)->gso_type = 0;
         }
 
-        /* Adjust counters and hints for the newly sacked sequence range but
-         * discard the return value since prev is already marked.
-         */
-        tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
-                        start_seq, end_seq, dup_sack, pcount);
-
         /* Difference in this won't matter, both ACKed by the same cumul. ACK */
         TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS);
 
@@ -1583,6 +1585,10 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
                 }
         }
 
+        /* tcp_sacktag_one() won't SACK-tag ranges below snd_una */
+        if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una))
+                goto fallback;
+
         if (!skb_shift(prev, skb, len))
                 goto fallback;
         if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))
@@ -2567,6 +2573,7 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
 
                 if (cnt > packets) {
                         if ((tcp_is_sack(tp) && !tcp_is_fack(tp)) ||
+                            (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) ||
                             (oldcnt >= packets))
                                 break;