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prevent UB in arena reservation

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daanx 2024-06-01 12:29:48 -07:00
parent 87d088b7e0
commit 616db104a9
2 changed files with 15 additions and 1 deletions
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8
src/arena.c
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@ -358,8 +358,14 @@ static bool mi_arena_reserve(size_t req_size, bool allow_large, mi_arena_id_t re
arena_reserve = arena_reserve/4; // be conservative if virtual reserve is not supported (for WASM for example)
}
arena_reserve = _mi_align_up(arena_reserve, MI_ARENA_BLOCK_SIZE);
arena_reserve = _mi_align_up(arena_reserve, MI_SEGMENT_SIZE);
if (arena_count >= 8 && arena_count <= 128) {
arena_reserve = ((size_t)1<<(arena_count/8)) * arena_reserve; // scale up the arena sizes exponentially
// scale up the arena sizes exponentially every 8 entries (128 entries get to 589TiB)
const size_t multiplier = (size_t)1 << _mi_clamp(arena_count/8, 0, 16 );
size_t reserve = 0;
if (!mi_mul_overflow(multiplier, arena_reserve, &reserve)) {
arena_reserve = reserve;
}
}
if (arena_reserve < req_size) return false; // should be able to at least handle the current allocation size