From: Paolo Abeni <pabeni@redhat.com>
In case of DSS corruption, the MPTCP protocol tries to avoid the subflow
reset if fallback is possible. Such corruptions happen in the receive
path; to ensure fallback is possible the stack additionally needs to
check for OoO data, otherwise the fallback will break the data stream.
Fixes: e32d262c89e2 ("mptcp: handle consistently DSS corruption")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/598
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
net/mptcp/protocol.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e30e9043a694..6f0e8f670d83 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -76,6 +76,13 @@ bool __mptcp_try_fallback(struct mptcp_sock *msk, int fb_mib)
if (__mptcp_check_fallback(msk))
return true;
+ /* The caller possibly is not holding the msk socket lock, but
+ * in the fallback case only the current subflow is touching
+ * the OoO queue.
+ */
+ if (!RB_EMPTY_ROOT(&msk->out_of_order_queue))
+ return false;
+
spin_lock_bh(&msk->fallback_lock);
if (!msk->allow_infinite_fallback) {
spin_unlock_bh(&msk->fallback_lock);
--
2.51.0