diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index d762f21a37..412f883e9c 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -6827,7 +6827,7 @@ spa_tryimport(nvlist_t *tryconfig)
 	 */
 	char *name = kmem_alloc(MAXPATHLEN, KM_SLEEP);
 	(void) snprintf(name, MAXPATHLEN, "%s-%llx-%s",
-	    TRYIMPORT_NAME, (u_longlong_t)curthread, poolname);
+	    TRYIMPORT_NAME, (u_longlong_t)(uintptr_t)curthread, poolname);
 
 	mutex_enter(&spa_namespace_lock);
 	spa = spa_add(name, tryconfig, NULL);