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Couple duplicate memory interval tree inserts/deletes were leading to some use-after-frees/page faults. Cleaned that up. Added some resource tree debug code along the way. Also, caught something subtle (noted in code). I didn't consider the following scenario: Heap tries to allocate pages; the allocator notices it needs to bring in more fresh pages, and notifies the heap (via a callback); the heap allocs the fresh pages (from the microkernel), maps them, and inserts those pages into the memory interval tree; the memory interval tree kmallocs a tree node; kmalloc calls back into the heap to grow a slab cache. That last bit could be a potential problem (recursive call back into the heap before we finish the original call). Lucky for me, I designed the heap/allocator so that (1) the pages from the first call are already marked as in use (not on a free list); (2) the fresh pages are mapped first *before* inserting the corresponding cptr into the memory interval tree. The Linux kernel deals with these same recursive issues (they resolve them using special GFP_ flags so that you don't get recursion). In my case, the recursion is risky, but works.
c543053a
