6.6-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Abeni pabeni@redhat.com
commit 013e3179dbd2bc756ce1dd90354abac62f65b739 upstream.
mptcp_rcv_space_init() is supposed to happen under the msk socket lock, but active msk socket does that without such protection.
Leverage the existing mptcp_propagate_state() helper to that extent. We need to ensure mptcp_rcv_space_init will happen before mptcp_rcv_space_adjust(), and the release_cb does not assure that: explicitly check for such condition.
While at it, move the wnd_end initialization out of mptcp_rcv_space_init(), it never belonged there.
Note that the race does not produce ill effect in practice, but change allows cleaning-up and defying better the locking model.
Fixes: a6b118febbab ("mptcp: add receive buffer auto-tuning") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/protocol.c | 10 ++++++---- net/mptcp/protocol.h | 3 ++- net/mptcp/subflow.c | 4 ++-- 3 files changed, 10 insertions(+), 7 deletions(-)
--- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1967,6 +1967,9 @@ static void mptcp_rcv_space_adjust(struc if (copied <= 0) return;
+ if (!msk->rcvspace_init) + mptcp_rcv_space_init(msk, msk->first); + msk->rcvq_space.copied += copied;
mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); @@ -3151,6 +3154,7 @@ static int mptcp_disconnect(struct sock msk->bytes_received = 0; msk->bytes_sent = 0; msk->bytes_retrans = 0; + msk->rcvspace_init = 0;
WRITE_ONCE(sk->sk_shutdown, 0); sk_error_report(sk); @@ -3238,6 +3242,7 @@ void mptcp_rcv_space_init(struct mptcp_s { const struct tcp_sock *tp = tcp_sk(ssk);
+ msk->rcvspace_init = 1; msk->rcvq_space.copied = 0; msk->rcvq_space.rtt_us = 0;
@@ -3248,8 +3253,6 @@ void mptcp_rcv_space_init(struct mptcp_s TCP_INIT_CWND * tp->advmss); if (msk->rcvq_space.space == 0) msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; - - WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); }
static struct sock *mptcp_accept(struct sock *ssk, int flags, int *err, @@ -3507,10 +3510,9 @@ void mptcp_finish_connect(struct sock *s WRITE_ONCE(msk->write_seq, subflow->idsn + 1); WRITE_ONCE(msk->snd_nxt, msk->write_seq); WRITE_ONCE(msk->snd_una, msk->write_seq); + WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
mptcp_pm_new_connection(msk, ssk, 0); - - mptcp_rcv_space_init(msk, ssk); }
void mptcp_sock_graft(struct sock *sk, struct socket *parent) --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -301,7 +301,8 @@ struct mptcp_sock { nodelay:1, fastopening:1, in_accept_queue:1, - free_first:1; + free_first:1, + rcvspace_init:1; struct work_struct work; struct sk_buff *ooo_last_skb; struct rb_root out_of_order_queue; --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -424,6 +424,8 @@ void __mptcp_sync_state(struct sock *sk, struct mptcp_sock *msk = mptcp_sk(sk);
__mptcp_propagate_sndbuf(sk, msk->first); + if (!msk->rcvspace_init) + mptcp_rcv_space_init(msk, msk->first); if (sk->sk_state == TCP_SYN_SENT) { inet_sk_state_store(sk, state); sk->sk_state_change(sk); @@ -545,7 +547,6 @@ static void subflow_finish_connect(struc } } else if (mptcp_check_fallback(sk)) { fallback: - mptcp_rcv_space_init(msk, sk); mptcp_propagate_state(parent, sk); } return; @@ -1736,7 +1737,6 @@ static void subflow_state_change(struct msk = mptcp_sk(parent); if (subflow_simultaneous_connect(sk)) { mptcp_do_fallback(sk); - mptcp_rcv_space_init(msk, sk); pr_fallback(msk); subflow->conn_finished = 1; mptcp_propagate_state(parent, sk);