diff --git a/src/gc-pages.c b/src/gc-pages.c
index 82842cc9aa5f6..7da72d4a43174 100644
--- a/src/gc-pages.c
+++ b/src/gc-pages.c
@@ -99,7 +99,7 @@ NOINLINE jl_gc_pagemeta_t *jl_gc_alloc_page(void) JL_NOTSAFEPOINT
 void jl_gc_free_page(jl_gc_pagemeta_t *pg) JL_NOTSAFEPOINT
 {
     void *p = pg->data;
-    gc_alloc_map_set(p, 0);
+    gc_alloc_map_set((char*)p, 0);
     // tell the OS we don't need these pages right now
     size_t decommit_size = GC_PAGE_SZ;
     if (GC_PAGE_SZ < jl_page_size) {