From: Mat Martineau mathew.j.martineau@linux.intel.com
[ Upstream commit a657430260e5437df16004c8c317821d946b5ead ]
When setting up a subflow's flags for sending MP_PRIO MPTCP options, the subflow socket lock was not held while reading and modifying several struct members that are also read and modified in mptcp_write_options().
Acquire the subflow socket lock earlier and send the MP_PRIO ACK with that lock already acquired. Add a new variant of the mptcp_subflow_send_ack() helper to use with the subflow lock held.
Fixes: 067065422fcd ("mptcp: add the outgoing MP_PRIO support") Acked-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau mathew.j.martineau@linux.intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/pm_netlink.c | 5 ++++- net/mptcp/protocol.c | 9 +++++++-- net/mptcp/protocol.h | 1 + 3 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 88077ea02ed3..3384569f73b8 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -721,11 +721,13 @@ static int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk, mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); struct mptcp_addr_info local; + bool slow;
local_address((struct sock_common *)ssk, &local); if (!addresses_equal(&local, addr, addr->port)) continue;
+ slow = lock_sock_fast(ssk); if (subflow->backup != bkup) msk->last_snd = NULL; subflow->backup = bkup; @@ -733,7 +735,8 @@ static int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk, subflow->request_bkup = bkup;
pr_debug("send ack for mp_prio"); - mptcp_subflow_send_ack(ssk); + __mptcp_subflow_send_ack(ssk); + unlock_sock_fast(ssk, slow);
return 0; } diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 713077eef04a..b0fb1fc0bd4a 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -506,13 +506,18 @@ static bool tcp_can_send_ack(const struct sock *ssk) (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN)); }
+void __mptcp_subflow_send_ack(struct sock *ssk) +{ + if (tcp_can_send_ack(ssk)) + tcp_send_ack(ssk); +} + void mptcp_subflow_send_ack(struct sock *ssk) { bool slow;
slow = lock_sock_fast(ssk); - if (tcp_can_send_ack(ssk)) - tcp_send_ack(ssk); + __mptcp_subflow_send_ack(ssk); unlock_sock_fast(ssk, slow); }
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 2aab5aff6bcd..ad36a05aa67d 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -584,6 +584,7 @@ void __init mptcp_subflow_init(void); void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how); void mptcp_close_ssk(struct sock *sk, struct sock *ssk, struct mptcp_subflow_context *subflow); +void __mptcp_subflow_send_ack(struct sock *ssk); void mptcp_subflow_send_ack(struct sock *ssk); void mptcp_subflow_reset(struct sock *ssk); void mptcp_subflow_queue_clean(struct sock *ssk);