old mode 100644
new mode 100755
--- a/js/src/vm/ArrayBufferObject.cpp
+++ b/js/src/vm/ArrayBufferObject.cpp
@@ -674,21 +674,21 @@ WasmArrayRawBuffer::Allocate(uint32_t nu
 }
 
 /* static */ void
 WasmArrayRawBuffer::Release(void* mem)
 {
     WasmArrayRawBuffer* header = (WasmArrayRawBuffer*)((uint8_t*)mem - sizeof(WasmArrayRawBuffer));
     uint8_t* base = header->basePointer();
     MOZ_RELEASE_ASSERT(header->mappedSize() <= SIZE_MAX - gc::SystemPageSize());
-    size_t mappedSizeWithHeader = header->mappedSize() + gc::SystemPageSize();
 
 # ifdef XP_WIN
     VirtualFree(base, 0, MEM_RELEASE);
 # else  // XP_WIN
+    size_t mappedSizeWithHeader = header->mappedSize() + gc::SystemPageSize();
     munmap(base, mappedSizeWithHeader);
 # endif  // !XP_WIN
 
 #  if defined(MOZ_VALGRIND) && defined(VALGRIND_ENABLE_ADDR_ERROR_REPORTING_IN_RANGE)
     VALGRIND_ENABLE_ADDR_ERROR_REPORTING_IN_RANGE(base, mappedSizeWithHeader);
 #  endif
 }