Re: [libvirt] [PATCH] virBitmapFree: Change the function to a macro

The virBitmapFree is: void virBitmapFree(virBitmapPtr bitmap) { if (bitmap) { VIR_FREE(bitmap->map); VIR_FREE(bitmap); } } Bitmap is a parameter (formal parameter). The address which is pointed by Bitmap is the same as argument(actual parameter) pointed. In " VIR_FREE(bitmap);", it frees the same address. But only assigns the NULL to the Bitmap, not to the argument(actual parameter). After calling virBitmapFree, if there is not assigning NULL to the argument(actual parameter), and using this argument(actual parameter) to call the virBitmapFree again, it will free an already freed address. It will generate a crash. There are 3 solutions: 1> After call virBitmapFree function, add a assignment which is assign NULL to the argument(actual parameter) of virBitmapFree. 2> Change the virBitmapFree to : void virBitmapFree(virBitmapPtr *bitmap) { if (*bitmap) { VIR_FREE((*bitmap)->map); VIR_FREE(*bitmap); } } And change all virBitmapFree calling from virBitmapFree(abc) to virBitmapFree(&abc) 3> change the virBitmapFree to a macro, like my first mail. Because the 1 and 2 solutions will modify the code in many code segment. So, I prefer the 3 solution.