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Ryan Houdek
be96cb7bd0
Spurred on by #3421. To ensure that applications don't take advantage of small address wrap around, allocate the second 4GB of virtual memory. Some context. Linux always reserves the first 16KB of virtual address space (unless you tinker with some settings which nobody should do). Example of 32-bit code: lea eax, [0xffff_0000] mov ebx, [eax + 0x1_0000] The address calculated by the mov will wrap around to 0x0 which will result in SIGSEGV. If FEX messes up zero extensions then it would try to access 0x1_0000_0000 instead. This could result in a 32-bit application potentially accessing some FEX memory instead of crashing. Add this safety net which will still SIGSEGV and we will be able to see the crash.