tcp: do not recycle cloned skbs (858f5017) · Commits · 戴 / test

It is illegal to change arbitrary fields in skb_shared_info if the skb is cloned. Before calling skb_zcopy_clear() we need to ensure this rule, therefore we need to move the test from sk_stream_alloc_skb() to sk_wmem_free_skb() Fixes: ("tcp: fix zerocopy and notsent_lowat issues") Signed-off-by:

Eric Dumazet <edumazet@google.com> Diagnosed-by:

Willem de Bruijn <willemb@google.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

include/net/sock.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -1473,7 +1473,7 @@ static inline void sk_wmem_free_skb(struct sock sk, struct sk_buff skb)
		sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
		sk->sk_wmem_queued -= skb->truesize;
		sk_mem_uncharge(sk, skb->truesize);
		if (!sk->sk_tx_skb_cache) {
		if (!sk->sk_tx_skb_cache && !skb_cloned(skb)) {
		skb_zcopy_clear(skb, true);
		sk->sk_tx_skb_cache = skb;
		return;

net/ipv4/tcp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -855,7 +855,7 @@ struct sk_buff sk_stream_alloc_skb(struct sock sk, int size, gfp_t gfp,

		if (likely(!size)) {
		skb = sk->sk_tx_skb_cache;
		if (skb && !skb_cloned(skb)) {
		if (skb) {
		skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
		sk->sk_tx_skb_cache = NULL;
		pskb_trim(skb, 0);

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