Commit 5cd6e0ad authored by Matthieu Baerts (NGI0)'s avatar Matthieu Baerts (NGI0) Committed by Jakub Kicinski
Browse files

mptcp: pm: ADD_ADDR rtx: fix potential data-race 



This mptcp_pm_add_timer() helper is executed as a timer callback in
softirq context. To avoid any data races, the socket lock needs to be
held with bh_lock_sock().

If the socket is in use, retry again soon after, similar to what is done
with the keepalive timer.

Fixes: 00cfd77b ("mptcp: retransmit ADD_ADDR when timeout")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarMat Martineau <martineau@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260505-net-mptcp-pm-fixes-7-1-rc3-v1-3-fca8091060a4@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 03f324f3

net/mptcp/pm.c

+8 −0
Original line number Diff line number Diff line
@@ -337,6 +337,13 @@ static void mptcp_pm_add_timer(struct timer_list *timer) 
	if (inet_sk_state_load(sk) == TCP_CLOSE)

		return;



	bh_lock_sock(sk);

	if (sock_owned_by_user(sk)) {

		/* Try again later. */

		sk_reset_timer(sk, timer, jiffies + HZ / 20);

		goto out;

	}



	if (mptcp_pm_should_add_signal_addr(msk)) {

		sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);

		goto out;
@@ -365,6 +372,7 @@ static void mptcp_pm_add_timer(struct timer_list *timer) 
		mptcp_pm_subflow_established(msk);



out:

	bh_unlock_sock(sk);

	__sock_put(sk);

}