tcp: fix splice() and tcp collapsing interaction
Under unusual circumstances, TCP collapse can split a big GRO TCP packet
while its being used in a splice(socket->pipe) operation.
skb_splice_bits() releases the socket lock before calling
splice_to_pipe().
[ 1081.353685] WARNING: at net/ipv4/tcp.c:1330 tcp_cleanup_rbuf+0x4d/0xfc()
[ 1081.371956] Hardware name: System x3690 X5 -[7148Z68]-
[ 1081.391820] cleanup rbuf bug: copied AD3BCF1 seq AD370AF rcvnxt AD3CF13
To fix this problem, we must eat skbs in tcp_recv_skb().
Remove the inline keyword from tcp_recv_skb() definition since
it has three call sites.
Reported-by: Christian Becker <c.becker@traviangames.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 5f173dc..2aa69c8 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1428,12 +1428,12 @@
}
#endif
-static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
+static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
{
struct sk_buff *skb;
u32 offset;
- skb_queue_walk(&sk->sk_receive_queue, skb) {
+ while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
offset = seq - TCP_SKB_CB(skb)->seq;
if (tcp_hdr(skb)->syn)
offset--;
@@ -1441,6 +1441,11 @@
*off = offset;
return skb;
}
+ /* This looks weird, but this can happen if TCP collapsing
+ * splitted a fat GRO packet, while we released socket lock
+ * in skb_splice_bits()
+ */
+ sk_eat_skb(sk, skb, false);
}
return NULL;
}
@@ -1520,8 +1525,10 @@
tcp_rcv_space_adjust(sk);
/* Clean up data we have read: This will do ACK frames. */
- if (copied > 0)
+ if (copied > 0) {
+ tcp_recv_skb(sk, seq, &offset);
tcp_cleanup_rbuf(sk, copied);
+ }
return copied;
}
EXPORT_SYMBOL(tcp_read_sock);