From cfbadb2f1e8bd6c695729b5ec4746d483ada4870 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Wed, 15 Jul 2020 22:27:05 +0200 Subject: [PATCH] mptcp: silence warning in subflow_data_ready() since commit d47a72152097 ("mptcp: fix race in subflow_data_ready()"), it is possible to observe a regression in MP_JOIN kselftests. For sockets in TCP_CLOSE state, it's not sufficient to just wake up the main socket: we also need to ensure that received data are made available to the reader. Silence the WARN_ON_ONCE() in these cases: it preserves the syzkaller fix and restores kselftests when they are ran as follows: # while true; do > make KBUILD_OUTPUT=/tmp/kselftest TARGETS=net/mptcp kselftest > done Reported-by: Florian Westphal Fixes: d47a72152097 ("mptcp: fix race in subflow_data_ready()") Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/47 Signed-off-by: Davide Caratti --- net/mptcp/subflow.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 9f7f3772c13c5..519122e66f172 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -869,18 +869,19 @@ void mptcp_space(const struct sock *ssk, int *space, int *full_space) static void subflow_data_ready(struct sock *sk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); + u16 state = 1 << inet_sk_state_load(sk); struct sock *parent = subflow->conn; struct mptcp_sock *msk; msk = mptcp_sk(parent); - if ((1 << inet_sk_state_load(sk)) & (TCPF_LISTEN | TCPF_CLOSE)) { + if (state & TCPF_LISTEN) { set_bit(MPTCP_DATA_READY, &msk->flags); parent->sk_data_ready(parent); return; } WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable && - !subflow->mp_join); + !subflow->mp_join && !(state & TCPF_CLOSE)); if (mptcp_subflow_data_available(sk)) mptcp_data_ready(parent, sk);