6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Matthieu Baerts (NGI0)" matttbe@kernel.org
[ Upstream commit 833d4313bc1e9e194814917d23e8874d6b651649 ]
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) matttbe@kernel.org Reviewed-by: Simon Horman horms@kernel.org Reviewed-by: Kuniyuki Iwashima kuniyu@google.com Link: https://patch.msgid.link/20250918-net-next-mptcp-blackhole-reset-loopback-v1... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/ctrl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/mptcp/ctrl.c +++ b/net/mptcp/ctrl.c @@ -387,7 +387,7 @@ 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(); }