Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Pull networking fixes from David Miller:
 "Two stragglers:

   1) The new code that adds new flushing semantics to GRO can cause SKB
      pointer list corruption, manage the lists differently to avoid the
      OOPS.  Fix from Eric Dumazet.

   2) When TCP fast open does a retransmit of data in a SYN-ACK or
      similar, we update retransmit state that we shouldn't triggering a
      WARN_ON later.  Fix from Yuchung Cheng."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  net: gro: fix possible panic in skb_gro_receive()
  tcp: bug fix Fast Open client retransmission

6 files changed, 24 insertions, 9 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f8eda0276f03..a848ffc327f4 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1488,6 +1488,9 @@ struct napi_gro_cb {
 
 	/* Used in ipv6_gro_receive() */
 	int	proto;
+
+	/* used in skb_gro_receive() slow path */
+	struct sk_buff *last;
 };
 
 #define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 6feeccd83dd7..4af45e33105d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -525,6 +525,7 @@ static inline __u32 cookie_v6_init_sequence(struct sock *sk,
 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
 				      int nonagle);
 extern bool tcp_may_send_now(struct sock *sk);
+extern int __tcp_retransmit_skb(struct sock *, struct sk_buff *);
 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
 extern void tcp_retransmit_timer(struct sock *sk);
 extern void tcp_xmit_retransmit_queue(struct sock *);
diff --git a/net/core/dev.c b/net/core/dev.c
index c0946cb2b354..e5942bf45a6d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3451,6 +3451,8 @@ static int napi_gro_complete(struct sk_buff *skb)
 	struct list_head *head = &ptype_base[ntohs(type) & PTYPE_HASH_MASK];
 	int err = -ENOENT;
 
+	BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb));
+
 	if (NAPI_GRO_CB(skb)->count == 1) {
 		skb_shinfo(skb)->gso_size = 0;
 		goto out;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 4007c1437fda..3f0636cd76cd 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3004,7 +3004,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
 	skb_shinfo(nskb)->gso_size = pinfo->gso_size;
 	pinfo->gso_size = 0;
 	skb_header_release(p);
-	nskb->prev = p;
+	NAPI_GRO_CB(nskb)->last = p;
 
 	nskb->data_len += p->len;
 	nskb->truesize += p->truesize;
@@ -3030,8 +3030,8 @@ merge:
 
 	__skb_pull(skb, offset);
 
-	p->prev->next = skb;
-	p->prev = skb;
+	NAPI_GRO_CB(p)->last->next = skb;
+	NAPI_GRO_CB(p)->last = skb;
 	skb_header_release(skb);
 
 done:
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 609ff98aeb47..181fc8234a52 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5645,7 +5645,11 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
 	tcp_fastopen_cache_set(sk, mss, cookie, syn_drop);
 
 	if (data) { /* Retransmit unacked data in SYN */
-		tcp_retransmit_skb(sk, data);
+		tcp_for_write_queue_from(data, sk) {
+			if (data == tcp_send_head(sk) ||
+			    __tcp_retransmit_skb(sk, data))
+				break;
+		}
 		tcp_rearm_rto(sk);
 		return true;
 	}
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 2798706cb063..948ac275b9b5 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2309,12 +2309,11 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *to,
  * state updates are done by the caller.  Returns non-zero if an
  * error occurred which prevented the send.
  */
-int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
+int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	unsigned int cur_mss;
-	int err;
 
 	/* Inconslusive MTU probe */
 	if (icsk->icsk_mtup.probe_size) {
@@ -2387,11 +2386,17 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	if (unlikely(NET_IP_ALIGN && ((unsigned long)skb->data & 3))) {
 		struct sk_buff *nskb = __pskb_copy(skb, MAX_TCP_HEADER,
 						   GFP_ATOMIC);
-		err = nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
-			     -ENOBUFS;
+		return nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
+			      -ENOBUFS;
 	} else {
-		err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
+		return tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
 	}
+}
+
+int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	int err = __tcp_retransmit_skb(sk, skb);
 
 	if (err == 0) {
 		/* Update global TCP statistics. */