diff mbox series

[net-next,v2,10/11] tcp: clean ext on tx recycle

Message ID 20191217002455.24849-11-mathew.j.martineau@linux.intel.com
State Deferred, archived
Headers show
Series Multipath TCP: Prerequisites | expand

Commit Message

Mat Martineau Dec. 17, 2019, 12:24 a.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

Otherwise we will find stray/unexpected/old extensions value on next
iteration.

On tcp_write_xmit() we can end-up splitting an already queued skb in two
parts, via tso_fragment(). The newly created skb can be allocated via
the tx cache and an upper layer will not be aware of it, so that upper
layer cannot set the ext properly.

Resetting the ext on recycle ensures that stale data is not propagated
in to packet headers or elsewhere.

An alternative would be add an additional hook in tso_fragment() or in
sk_stream_alloc_skb() to init the ext for upper layers that need it.

Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 include/net/sock.h | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/include/net/sock.h b/include/net/sock.h
index 0930f46c600c..7eb66edb8abe 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1474,6 +1474,7 @@  static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
 	sk_mem_uncharge(sk, skb->truesize);
 	if (static_branch_unlikely(&tcp_tx_skb_cache_key) &&
 	    !sk->sk_tx_skb_cache && !skb_cloned(skb)) {
+		skb_ext_reset(skb);
 		skb_zcopy_clear(skb, true);
 		sk->sk_tx_skb_cache = skb;
 		return;