Commit d68be71e authored Apr 26, 2017 by Davide Caratti Committed by David S. Miller Apr 30, 2017

tcp: fix access to sk->sk_state in tcp_poll()



avoid direct access to sk->sk_state when tcp_poll() is called on a socket
using active TCP fastopen with deferred connect. Use local variable
'state', which stores the result of sk_state_load(), like it was done in
commit 00fd38d9 ("tcp: ensure proper barriers in lockless contexts").

Fixes: 19f6d3f3 ("net/tcp-fastopen: Add new API support")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent d1f496fd

net/ipv4/tcp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -533,7 +533,7 @@ unsigned int tcp_poll(struct file file, struct socket sock, poll_table *wait)

		if (tp->urg_data & TCP_URG_VALID)
		mask \|= POLLPRI;
		} else if (sk->sk_state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
		} else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
		/* Active TCP fastopen socket with defer_connect
		* Return POLLOUT so application can call write()
		* in order for kernel to generate SYN+data

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