6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Abeni <pabeni@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
