cifs: protect updating server->dstaddr with a spinlock

stable inclusion
from linux-4.19.122
commit 6c662c519277d9d94f4d146b7c05e67a426b91a7

--------------------------------

[ Upstream commit fada37f6 ]

We use a spinlock while we are reading and accessing the destination address for a server.
We need to also use this spinlock to protect when we are modifying this address from
reconn_set_ipaddr().
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/cifs/connect.c

@@ -353,8 +353,10 @@ static int reconn_set_ipaddr(struct TCP_Server_Info *server)
 		return rc;
 	}
 
+	spin_lock(&cifs_tcp_ses_lock);
 	rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,
 				  strlen(ipaddr));
+	spin_unlock(&cifs_tcp_ses_lock);
 	kfree(ipaddr);
 
 	return !rc ? -1 : 0;