diff --git a/libgralloc/mapper.cpp b/libgralloc/mapper.cpp
index 197c372..b3e371a 100644
--- a/libgralloc/mapper.cpp
+++ b/libgralloc/mapper.cpp
@@ -117,7 +117,10 @@
             }
         }
     }
+    /* need to initialize the pointer to NULL otherwise unmapping for that
+     * buffer happens twice which leads to crash */
     hnd->base = 0;
+    hnd->base_metadata = 0;
     return 0;
 }
 
@@ -144,6 +147,7 @@
 
     private_handle_t* hnd = (private_handle_t*)handle;
     hnd->base = 0;
+    hnd->base_metadata = 0;
     void *vaddr;
     int err = gralloc_map(module, handle, &vaddr);
     if (err) {
@@ -190,6 +194,7 @@
         gralloc_unmap(module, handle);
     }
     hnd->base = 0;
+    hnd->base_metadata = 0;
     // Release the genlock
     if (-1 != hnd->genlockHandle) {
         return genlock_release_lock((native_handle_t *)handle);