Subject: [PATCH] sunrpc: bug on rpc_task_set_client when no client is present.

From: Thiago Rafael Becker <[email-masked]>
Date: Mon, 18 Oct 2021 09:38:12 -0300

If we pass a NULL client to rpc_task_set_client and no client is
attached to the task, then the kernel will crash later. Antecipate the
crash by checking if a client is available for the task.

Signed-off-by: Thiago Rafael Becker <[email-masked]>
---
 net/sunrpc/clnt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index f056ff931444..ccbc9a9715da 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1076,7 +1076,7 @@ void rpc_task_set_transport(struct rpc_task *task, struct rpc_clnt *clnt)
 static
 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 {
-
+	BUG_ON(clnt == NULL && task->tk_client == NULL);
 	if (clnt != NULL) {
 		rpc_task_set_transport(task, clnt);
 		task->tk_client = clnt;
-- 
2.31.1