the realloc may change pointer

[wiltchamberian]

you use realloc to add block ,but realloc may return a pointer
different from the previous, if this happen,
all the allocated object pointer will be invalid.
this is a serious issue.
so i advise not to use realloc, but alloc a new chunk, then use
lists to connect the chunks.

[bitshifter]

It's been a while since I looked at this code. But from what I can see the only places that realloc reassign the pointer and I don't believe anything points to memory inside this block, so nothing should end up dangling if the buffer moves in memory.

Have you hit a specific bug with this code?