| Message ID | 1523433445-7596-1-git-send-email-ka-cheong.poon@oracle.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] rds: MP-RDS may use an invalid c_path | expand |
On 4/11/18 12:57 AM, Ka-Cheong Poon wrote: > 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> > --- Thanks for posting the fix upstream as well. Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
From: Ka-Cheong Poon <ka-cheong.poon@oracle.com> Date: Wed, 11 Apr 2018 00:57:25 -0700 > 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> Applied and queued up for -stable, thanks.
diff --git a/net/rds/send.c b/net/rds/send.c index acad042..94c7f74 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; }
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> --- net/rds/send.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)