diff --git a/core/shared/mem-alloc/ems/ems_alloc.c b/core/shared/mem-alloc/ems/ems_alloc.c
index 51b55692..3dc63170 100644
--- a/core/shared/mem-alloc/ems/ems_alloc.c
+++ b/core/shared/mem-alloc/ems/ems_alloc.c
@@ -570,7 +570,6 @@ gc_realloc_vo_internal(void *vheap, void *ptr, gc_size_t size,
         }
     }
 
-
     hmu = alloc_hmu_ex(heap, tot_size);
     if (!hmu)
         goto finish;
@@ -578,6 +577,7 @@ gc_realloc_vo_internal(void *vheap, void *ptr, gc_size_t size,
     bh_assert(hmu_get_size(hmu) >= tot_size);
     /* the total size allocated may be larger than
        the required size, reset it here */
+    tot_size = hmu_get_size(hmu);
     g_total_malloc += tot_size;
 
     hmu_set_ut(hmu, HMU_VO);
@@ -590,7 +590,6 @@ gc_realloc_vo_internal(void *vheap, void *ptr, gc_size_t size,
     ret = hmu_to_obj(hmu);
 
 finish:
-    os_mutex_unlock(&heap->lock);
 
     if (ret) {
         obj_size = tot_size - HMU_SIZE - OBJ_PREFIX_SIZE - OBJ_SUFFIX_SIZE;
@@ -599,10 +598,14 @@ finish:
             obj_size_old = tot_size_old - HMU_SIZE
                            - OBJ_PREFIX_SIZE - OBJ_SUFFIX_SIZE;
             bh_memcpy_s(ret, obj_size, obj_old, obj_size_old);
-            gc_free_vo(vheap, obj_old);
         }
     }
 
+    os_mutex_unlock(&heap->lock);
+
+    if (ret && obj_old)
+        gc_free_vo(vheap, obj_old);
+
     return ret;
 }