Uncapping the mock game (next commit) turned mock_game_test's hook/unhook storm
into a real stress test (thousands of presents/s instead of tens), which reliably
crashed the game on remove (0xC0000005) for dx9/dx11/dx12. Two races the slow
vsync'd mock had masked:
1. Trampoline use-after-free. remove_*_hooks did `hook = {}` (destroy) BEFORE the
DetourGate drain. Destroying a SafetyHook InlineHook frees its trampoline
immediately, but an in-flight detour about to call the original via .stdcall()
(the trampoline) then used freed memory. Fix: disable() first (restores the
original bytes under thread suspension, but KEEPS the trampoline alive) -> drain
-> only then destroy. Applied to present/d3d9/opengl/vk/xinput/mkb/focus.
2. Entry-window race in DetourGate::drain(). It returned the instant the active
count read zero, but a thread can be inside the detour yet not have reached its
Guard constructor (the prologue is unguarded), so the count reads zero while a
detour is about to run -- and the freed state is then used. Fix: Sleep(1) BEFORE
each zero-check; with the hook disabled no new detour starts, so any
already-entered thread registers within that window. This alone fixed dx11 (the
highest present rate, ~11000/s, which hit the window every storm).
Audio is unaffected (it uses vtable swaps, which keep a real original pointer, not
a trampoline). Full suite 21/21, and the storm now survives on every backend.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
BlackMark
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