rds: MP-RDS may use an invalid c_path (a43cced9) · Commits · 戴 / test

rds_sendmsg() calls rds_send_mprds_hash() to find a c_path to use to send a message. Suppose the RDS connection is not yet up. In rds_send_mprds_hash(), it does if (conn->c_npaths == 0) wait_event_interruptible(conn->c_hs_waitq, (conn->c_npaths != 0)); If it is interrupted before the connection is set up, rds_send_mprds_hash() will return a non-zero hash value. Hence rds_sendmsg() will use a non-zero c_path to send the message. But if the RDS connection ends up to be non-MP capable, the message will be lost as only the zero c_path can be used. Signed-off-by:

Ka-Cheong Poon <ka-cheong.poon@oracle.com> Acked-by:

Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/rds/send.c

+10 −5

Original line number	Original line	Diff line number	Diff line
	/*		/*
	* Copyright (c) 2006 Oracle. All rights reserved.		* Copyright (c) 2006, 2018 Oracle and/or its affiliates. All rights reserved.
	*		*
	* This software is available to you under a choice of one of two		* This software is available to you under a choice of one of two
	* licenses. You may choose to be licensed under the terms of the GNU		* licenses. You may choose to be licensed under the terms of the GNU
	@@ -1017,10 +1017,15 @@ static int rds_send_mprds_hash(struct rds_sock rs, struct rds_connection conn)
	if (conn->c_npaths == 0 && hash != 0) {		if (conn->c_npaths == 0 && hash != 0) {
	rds_send_ping(conn, 0);		rds_send_ping(conn, 0);

	if (conn->c_npaths == 0) {		/* The underlying connection is not up yet. Need to wait
	wait_event_interruptible(conn->c_hs_waitq,		* until it is up to be sure that the non-zero c_path can be
	(conn->c_npaths != 0));		* used. But if we are interrupted, we have to use the zero
	}		* c_path in case the connection ends up being non-MP capable.
			*/
			if (conn->c_npaths == 0)
			if (wait_event_interruptible(conn->c_hs_waitq,
			conn->c_npaths != 0))
			hash = 0;
	if (conn->c_npaths == 1)		if (conn->c_npaths == 1)
	hash = 0;		hash = 0;
	}		}

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