From: Paolo Abeni <pabeni@xxxxxxxxxx> [ Upstream commit 8555c6bfd5fddb1cf363d3cd157d70a1bb27f718 ] In case of memory pressure, mptcp_sendmsg() may call sk_stream_wait_memory() after succesfully xmitting some bytes. If the latter fails we currently return to the user-space the error code, ignoring the succeful xmit. Address the issue always checking for the xmitted bytes before mptcp_sendmsg() completes. Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Reviewed-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/mptcp/protocol.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -802,7 +802,6 @@ fallback: mptcp_set_timeout(sk, ssk); if (copied) { - ret = copied; tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle, size_goal); @@ -815,7 +814,7 @@ fallback: release_sock(ssk); out: release_sock(sk); - return ret; + return copied ? : ret; } static void mptcp_wait_data(struct sock *sk, long *timeo)