diff --git a/drivers/staging/lustre/lnet/selftest/rpc.c b/drivers/staging/lustre/lnet/selftest/rpc.c
index bb6aa2ea136b..2e9094bd889f 100644
--- a/drivers/staging/lustre/lnet/selftest/rpc.c
+++ b/drivers/staging/lustre/lnet/selftest/rpc.c
@@ -468,6 +468,7 @@ srpc_post_passive_rqtbuf(int service, int local, void *buf, int len,
 
 static int
 srpc_service_post_buffer(struct srpc_service_cd *scd, struct srpc_buffer *buf)
+	__must_hold(&scd->scd_lock)
 {
 	struct srpc_service	*sv = scd->scd_svc;
 	struct srpc_msg		*msg = &buf->buf_msg;