From: Matthieu Baerts (NGI0) Date: Thu, 18 Sep 2025 08:50:18 +0000 (+0200) Subject: mptcp: reset blackhole on success with non-loopback ifaces X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=833d4313bc1e9e194814917d23e8874d6b651649;p=users%2Fhch%2Fmisc.git mptcp: reset blackhole on success with non-loopback ifaces When a first MPTCP connection gets successfully established after a blackhole period, 'active_disable_times' was supposed to be reset when this connection was done via any non-loopback interfaces. Unfortunately, the opposite condition was checked: only reset when the connection was established via a loopback interface. Fixing this by simply looking at the opposite. This is similar to what is done with TCP FastOpen, see tcp_fastopen_active_disable_ofo_check(). This patch is a follow-up of a previous discussion linked to commit 893c49a78d9f ("mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable()."), see [1]. Fixes: 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/4209a283-8822-47bd-95b7-87e96d9b7ea3@kernel.org [1] Signed-off-by: Matthieu Baerts (NGI0) Reviewed-by: Simon Horman Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250918-net-next-mptcp-blackhole-reset-loopback-v1-1-bf5818326639@kernel.org Signed-off-by: Jakub Kicinski --- diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c index e8ffa62ec183..d96130e49942 100644 --- a/net/mptcp/ctrl.c +++ b/net/mptcp/ctrl.c @@ -507,7 +507,7 @@ void mptcp_active_enable(struct sock *sk) rcu_read_lock(); dst = __sk_dst_get(sk); dev = dst ? dst_dev_rcu(dst) : NULL; - if (dev && (dev->flags & IFF_LOOPBACK)) + if (!(dev && (dev->flags & IFF_LOOPBACK))) atomic_set(&pernet->active_disable_times, 0); rcu_read_unlock(); }