From c75293925f24630326abdf79751d980ec3878f65 Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Tue, 28 Jul 2020 15:12:09 -0700 Subject: [PATCH] mptcp: Safely read sequence number when lock isn't held The MPTCP socket's write_seq member should be read with READ_ONCE() when the msk lock is not held. Signed-off-by: Mat Martineau Signed-off-by: David S. Miller --- net/mptcp/protocol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index f264ea1..f2455a6 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1269,7 +1269,7 @@ static void mptcp_retransmit_handler(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); - if (atomic64_read(&msk->snd_una) == msk->write_seq) { + if (atomic64_read(&msk->snd_una) == READ_ONCE(msk->write_seq)) { mptcp_stop_timer(sk); } else { set_bit(MPTCP_WORK_RTX, &msk->flags); -- 2.7.4