http://bugs.winehq.org/show_bug.cgi?id=34095
--- Comment #5 from alexei.svitkine@gmail.com 2013-07-21 10:34:52 CDT --- Indeed, something is mapped at that address:
455a5000-54f55000 255680K rw-/rw- NONE - DEFAULT uwir=0 sub=0
There's a comment in the file that says the magic 0x50000000 is needed because there are pointers to that block and the code doesn't do relocating yet:
/* Presently the shared data structures use pointers. If the * files are not mapped into the same area, the pointers will no * longer make any sense :( * FIXME: In the future make the shared data structures have some * sort of fixup to make them independent between data spaces. * This will also require a rework of the session data stuff. */
Unless someone implements the above, it sounds to me like the simplest solution is to reserve that space early during startup, so that other stuff can't take it.