diff -urNp x-ref/net/sunrpc/xprt.c 2.4.20aa1/net/sunrpc/xprt.c
--- x-ref/net/sunrpc/xprt.c	2002-11-29 02:23:23.000000000 +0100
+++ 2.4.20aa1/net/sunrpc/xprt.c	2002-12-02 18:44:33.000000000 +0100
@@ -1245,6 +1245,7 @@ static void
 xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
 {
 	struct rpc_rqst	*req = task->tk_rqstp;
+	static spinlock_t xid_lock = SPIN_LOCK_UNLOCKED;
 	static u32	xid = 0;
 
 	if (!xid)
@@ -1255,9 +1256,15 @@ xprt_request_init(struct rpc_task *task,
 	req->rq_timeout = xprt->timeout;
 	req->rq_task	= task;
 	req->rq_xprt    = xprt;
+
+	/* We need to protect this counter with a spin lock,
+	 * otherwise we may end up with two requests that have
+	 * the same XID. --okir */
+	spin_lock(&xid_lock);
 	req->rq_xid     = xid++;
 	if (!xid)
 		xid++;
+	spin_unlock(&xid_lock);
 	INIT_LIST_HEAD(&req->rq_list);
 }