diff --git a/Makefile b/Makefile
index fb63c1ae..958c1fb8 100644
--- a/Makefile
+++ b/Makefile
@@ -39,7 +39,7 @@ jemalloc : $(JEMALLOC_STATICLIB)
 # skynet
 
 CSERVICE = snlua logger gate master harbor
-LUA_CLIB = skynet socketdriver int64 bson mongo md5 netpack cjson clientsocket memory
+LUA_CLIB = skynet socketdriver int64 bson mongo md5 netpack cjson clientsocket # memory
 
 SKYNET_SRC = skynet_main.c skynet_handle.c skynet_module.c skynet_mq.c \
   skynet_server.c skynet_start.c skynet_timer.c skynet_error.c \
diff --git a/skynet-src/malloc_hook.c b/skynet-src/malloc_hook.c
index c0d91355..bba82ac4 100644
--- a/skynet-src/malloc_hook.c
+++ b/skynet-src/malloc_hook.c
@@ -73,8 +73,7 @@ fill_prefix(char* ptr) {
 
 inline static void*
 clean_prefix(char* ptr) {
-    uint32_t* rawptr = (uint32_t*)ptr - 1;
-    size_t size = je_malloc_usable_size(rawptr);
+    size_t size = je_malloc_usable_size(ptr);
     uint32_t *p = (uint32_t *)(ptr + size - sizeof(uint32_t));
     uint32_t handle;
     memcpy(&handle, p, sizeof(handle));