Index: sys/ofed/drivers/infiniband/core/ib_ucma.c
===================================================================
--- sys/ofed/drivers/infiniband/core/ib_ucma.c
+++ sys/ofed/drivers/infiniband/core/ib_ucma.c
@@ -226,7 +226,7 @@
 		return NULL;
 
 	mutex_lock(&mut);
-	mc->id = idr_alloc(&multicast_idr, mc, 0, 0, GFP_KERNEL);
+	mc->id = idr_alloc(&multicast_idr, NULL, 0, 0, GFP_KERNEL);
 	mutex_unlock(&mut);
 	if (mc->id < 0)
 		goto error;
@@ -1384,6 +1384,10 @@
 		goto err3;
 	}
 
+	mutex_lock(&mut);
+	idr_replace(&multicast_idr, mc, mc->id);
+	mutex_unlock(&mut);
+
 	mutex_unlock(&file->mut);
 	ucma_put_ctx(ctx);
 	return 0;