Re: [PATCH v10 0/8] MR1628: ntdll: Implement Low Fragmentation Heap.

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about dlls/ntdll/heap.c:
>      err = "invalid previous free block pointer";
>  else if (!(block_get_flags( prev ) & BLOCK_FLAG_FREE) || block_get_type( prev ) != BLOCK_TYPE_FREE)
>      err = "invalid previous free block header";
> - else if ((next = next_block( subheap, block )))
> - else if ((next = next_block( subheap, block )) &&
> -
>         /* LFH blocks do not use BLOCK_FLAG_PREV_FREE or back pointer */
> -
>         !(block_get_flags( block ) & BLOCK_FLAG_LFH))

For accurate heap free checking, we should always assign `next = NULL` when validating LFH blocks.

```suggestion:-2+0
    else
    {
        /* LFH blocks do not use BLOCK_FLAG_PREV_FREE or back pointer */
        next = (block_get_flags( block ) & BLOCK_FLAG_LFH) ? NULL : next_block( subheap, block );
    }

if (!err && next)
```