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authorKa-Cheong Poon <ka-cheong.poon@oracle.com>2018-04-11 00:57:25 -0700
committerDavid S. Miller <davem@davemloft.net>2018-04-11 10:24:01 -0400
commita43cced9a348901f9015f4730b70b69e7c41a9c9 (patch)
treeec0daa4fc626f408f90f69d17705e24abb39c016
parent1cc5954f44150bb70cac07c3cc5df7cf0dfb61ec (diff)
rds: MP-RDS may use an invalid c_path
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>
-rw-r--r--net/rds/send.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/net/rds/send.c b/net/rds/send.c
index acad04243b41..94c7f74909be 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -1,5 +1,5 @@
/*
- * 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
* 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) {
rds_send_ping(conn, 0);
- if (conn->c_npaths == 0) {
- wait_event_interruptible(conn->c_hs_waitq,
- (conn->c_npaths != 0));
- }
+ /* The underlying connection is not up yet. Need to wait
+ * until it is up to be sure that the non-zero c_path can be
+ * 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)
hash = 0;
}