Size of SUBHEAP in heap.c

[Martin Profittlich]

Hello,

when trying to fix an issue with Guitar Rig 3 on Wine (Bug 10129, "Guitar Rig 3 crashes"), I found out something odd: The crash is affected by the size of the SUBHEAP structure in dlls/ntdll/heap.c. Just by adding 8 unused bytes to SUBHEAP, GR3 does not crash anymore. Add another 8 bytes, GR3 crashes again, yet another 8 bytes - no crash and so on.

The bug surfaced with this commit:

[1d063ae18d990343fc077dcbf650add797924018]
ntdll: Remove assumptions that the subheap is at the beginning of the memory block.

I don't think the commit is the cause of the problem. It merely changed the size of SUBHEAP to a problematic value.

I don't really understand the inner workings of heap.c. Does anyone have an idea what the cause might be, or where to look for more information?

Cheers,
Martin

P.S. Link to the bug: http://bugs.winehq.org/show_bug.cgi?id=10129





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