6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Abeni <pabeni@xxxxxxxxxx>
[ Upstream commit ce7356ae35943cc6494cc692e62d51a734062b7d ]
Additional active subflows - i.e. created by the in kernel path
manager - are included into the subflow list before starting the
3whs.
A racing recvmsg() spooling data received on an already established
subflow would unconditionally call tcp_cleanup_rbuf() on all the
current subflows, potentially hitting a divide by zero error on
the newly created ones.
Explicitly check that the subflow is in a suitable state before
invoking tcp_cleanup_rbuf().
Fixes: c76c6956566f ("mptcp: call tcp_cleanup_rbuf on subflows")
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Link: https://patch.msgid.link/02374660836e1b52afc91966b7535c8c5f7bafb0.1731060874.git.pabeni@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/mptcp/protocol.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f3e54c836ba56..7913ba6b5daa3 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2082,7 +2082,8 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
slow = lock_sock_fast(ssk);
WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
WRITE_ONCE(tcp_sk(ssk)->window_clamp, window_clamp);
- tcp_cleanup_rbuf(ssk, 1);
+ if (tcp_can_send_ack(ssk))
+ tcp_cleanup_rbuf(ssk, 1);
unlock_sock_fast(ssk, slow);
}
}
--
2.43.0
