netdev - Re: /proc/net/sockstat invalid memory accounting or memory leak in latest kernels? (trying to debug)

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Date:	Sun, 16 Nov 2014 21:01:36 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Denys Fedoryshchenko <nuclearcat@...learcat.com>
Cc:	Neal Cardwell <ncardwell@...gle.com>,
	Yuchung Cheng <ycheng@...gle.com>, netdev@...r.kernel.org
Subject: Re: /proc/net/sockstat invalid memory accounting or memory leak in
 latest kernels? (trying to debug)

On Sun, 2014-11-16 at 12:16 -0800, Eric Dumazet wrote:

> Thanks Denys !
> 
> Could you try following patch ?
> 
> Thanks !

Hmm.... I have an updated patch, sorry.

(A memcpy_fromiovec() has to be memcpy_fromiovecend() )

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index a3d453b94747..c2bbfcd9c0db 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2998,7 +2998,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_fastopen_request *fo = tp->fastopen_req;
-	int syn_loss = 0, space, i, err = 0, iovlen = fo->data->msg_iovlen;
+	int syn_loss = 0, space, err = 0;
 	struct sk_buff *syn_data = NULL, *data;
 	unsigned long last_syn_loss = 0;
 
@@ -3031,25 +3031,19 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
 	/* limit to order-0 allocations */
 	space = min_t(size_t, space, SKB_MAX_HEAD(MAX_TCP_HEADER));
 
-	syn_data = skb_copy_expand(syn, MAX_TCP_HEADER, space,
-				   sk->sk_allocation);
-	if (syn_data == NULL)
+	syn_data = sk_stream_alloc_skb(sk, space, sk->sk_allocation);
+	if (!syn_data)
 		goto fallback;
 
-	for (i = 0; i < iovlen && syn_data->len < space; ++i) {
-		struct iovec *iov = &fo->data->msg_iov[i];
-		unsigned char __user *from = iov->iov_base;
-		int len = iov->iov_len;
-
-		if (syn_data->len + len > space)
-			len = space - syn_data->len;
-		else if (i + 1 == iovlen)
-			/* No more data pending in inet_wait_for_connect() */
-			fo->data = NULL;
+	syn_data->ip_summed = CHECKSUM_PARTIAL;
+	memcpy(syn_data->cb, syn->cb, sizeof(syn->cb));
+	if (memcpy_fromiovecend(skb_put(syn_data, space),
+				fo->data->msg_iov, 0, space))
+		goto fallback;
 
-		if (skb_add_data(syn_data, from, len))
-			goto fallback;
-	}
+	/* No more data pending in inet_wait_for_connect() */
+	if (space == fo->size)
+		fo->data = NULL;
 
 	/* Queue a data-only packet after the regular SYN for retransmission */
 	data = pskb_copy(syn_data, sk->sk_allocation);
@@ -3101,13 +3095,10 @@ int tcp_connect(struct sock *sk)
 		return 0;
 	}
 
-	buff = alloc_skb_fclone(MAX_TCP_HEADER + 15, sk->sk_allocation);
-	if (unlikely(buff == NULL))
+	buff = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
+	if (unlikely(!buff))
 		return -ENOBUFS;
 
-	/* Reserve space for headers. */
-	skb_reserve(buff, MAX_TCP_HEADER);
-
 	tcp_init_nondata_skb(buff, tp->write_seq++, TCPHDR_SYN);
 	tp->retrans_stamp = tcp_time_stamp;
 	tcp_connect_queue_skb(sk, buff);


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