From: "Matthieu Baerts (NGI0)" <matttbe@xxxxxxxxxx> [ Upstream commit db75a16813aabae3b78c06b1b99f5e314c1f55d3 ] Recently, some fallback have been initiated, while the connection was not supposed to fallback. Add a safety check with a warning to detect when an wrong attempt to fallback is being done. This should help detecting any future issues quicker. Acked-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx> Link: https://patch.msgid.link/20250224-net-mptcp-misc-fixes-v1-3-f550f636b435@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/mptcp/protocol.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index b70a303e08287..7e2f70f22b05b 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -1194,6 +1194,8 @@ static inline void __mptcp_do_fallback(struct mptcp_sock *msk) pr_debug("TCP fallback already done (msk=%p)\n", msk); return; } + if (WARN_ON_ONCE(!READ_ONCE(msk->allow_infinite_fallback))) + return; set_bit(MPTCP_FALLBACK_DONE, &msk->flags); } -- 2.39.5
