diff --git a/lib/libutil/gr_util.c b/lib/libutil/gr_util.c
index 4583257d360f..f4a08c4544d5 100644
--- a/lib/libutil/gr_util.c
+++ b/lib/libutil/gr_util.c
@@ -452,7 +452,7 @@ gr_dup(const struct group *gr)
 		return (NULL);
 	/* point new gr_mem to end of struct + 1 */
 	if (gr->gr_mem != NULL)
-		newgr->gr_mem = (char **)newgr + sizeof(struct group);
+		newgr->gr_mem = (char **)((uintptr_t)newgr + sizeof(struct group));
 	else
 		newgr->gr_mem = NULL;
 	/* point dst after the end of all the gr_mem pointers in newgr */