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restrict max aligment boundary to prevent bug with segment determination (found by Matthew Parkinson).

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daan 2021-12-17 11:40:46 -08:00
parent 60790e9013
commit 684c2c82a7
3 changed files with 6 additions and 1 deletions
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src/alloc-aligned.c
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@ -20,6 +20,7 @@ static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t
mi_assert(alignment > 0);
if (mi_unlikely(size > PTRDIFF_MAX)) return NULL; // we don't allocate more than PTRDIFF_MAX (see <https://sourceware.org/ml/libc-announce/2019/msg00001.html>)
if (mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment))) return NULL; // require power-of-two (see <https://en.cppreference.com/w/c/memory/aligned_alloc>)
if (mi_unlikely(alignment>MI_ALIGNED_MAX)) return NULL; // we cannot align at a boundary larger than this (or otherwise we cannot find segment headers)
const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)`
// try if there is a small block available with just the right alignment