[PATCH AUTOSEL for 4.4 086/167] rds; Reset rs->rs_bound_addr in rds_add_bound() failure path

[Sasha Levin]

From: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx>

[ Upstream commit 7ae0c649c47f1c5d2db8cee6dd75855970af1669 ]

If the rds_sock is not added to the bind_hash_table, we must
reset rs_bound_addr so that rds_remove_bound will not trip on
this rds_sock.

rds_add_bound() does a rds_sock_put() in this failure path, so
failing to reset rs_bound_addr will result in a socket refcount
bug, and will trigger a WARN_ON with the stack shown below when
the application subsequently tries to close the PF_RDS socket.

     WARNING: CPU: 20 PID: 19499 at net/rds/af_rds.c:496 \
		rds_sock_destruct+0x15/0x30 [rds]
       :
     __sk_destruct+0x21/0x190
     rds_remove_bound.part.13+0xb6/0x140 [rds]
     rds_release+0x71/0x120 [rds]
     sock_release+0x1a/0x70
     sock_close+0xe/0x20
     __fput+0xd5/0x210
     task_work_run+0x82/0xa0
     do_exit+0x2ce/0xb30
     ? syscall_trace_enter+0x1cc/0x2b0
     do_group_exit+0x39/0xa0
     SyS_exit_group+0x10/0x10
     do_syscall_64+0x61/0x1a0

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx>
Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 net/rds/bind.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/rds/bind.c b/net/rds/bind.c
index b22ea956522b..e29b47193645 100644
--- a/net/rds/bind.c
+++ b/net/rds/bind.c
@@ -108,6 +108,7 @@ static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
 			  rs, &addr, (int)ntohs(*port));
 			break;
 		} else {
+			rs->rs_bound_addr = 0;
 			rds_sock_put(rs);
 			ret = -ENOMEM;
 			break;
-- 
2.14.1