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Fix tcmalloc compatibility issue with aligned_alloc #683

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Fix tcmalloc compatibility issue with aligned_alloc #683

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13 changes: 11 additions & 2 deletions include/utils.h
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Original file line number Diff line number Diff line change
@@ -1,9 +1,10 @@
// Copyright (c) Microsoft Corporation. All rights reserved.
// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license.

#pragma once

#include <errno.h>
#include <stdlib.h> // for posix_memalign

#include "common_includes.h"

Expand Down Expand Up @@ -259,7 +260,15 @@ inline void alloc_aligned(void **ptr, size_t size, size_t align)
if (IS_ALIGNED(size, align) == 0)
report_misalignment_of_requested_size(align);
#ifndef _WINDOWS
*ptr = ::aligned_alloc(align, size);
// Use posix_memalign instead of aligned_alloc for tcmalloc compatibility.
// posix_memalign is more compatible with tcmalloc and avoids "invalid pointer" errors
// when freeing memory allocated with aligned_alloc and freed with tcmalloc's free().
int ret = posix_memalign(ptr, align, size);
if (ret != 0)
{
*ptr = nullptr;
Comment on lines +263 to +269
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Copilot AI Mar 3, 2026

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posix_memalign requires align to be a power-of-two and a multiple of sizeof(void*) (and typically >= sizeof(void*)). There are existing call sites that pass align = 1 (e.g., PQDataStore allocates _quantized_data with align=1), which will now fail with EINVAL and terminate. Consider special-casing small/invalid alignments (e.g., treat align < sizeof(void*) as sizeof(void*), or fall back to malloc when no special alignment is needed), and/or explicitly validate align and surface a clearer error than "Memory Allocation Failed" for EINVAL.

Suggested change
// Use posix_memalign instead of aligned_alloc for tcmalloc compatibility.
// posix_memalign is more compatible with tcmalloc and avoids "invalid pointer" errors
// when freeing memory allocated with aligned_alloc and freed with tcmalloc's free().
int ret = posix_memalign(ptr, align, size);
if (ret != 0)
{
*ptr = nullptr;
// Normalize and validate alignment for posix_memalign.
// posix_memalign requires that the alignment be a power of two and
// a multiple of sizeof(void*), and typically at least sizeof(void*).
size_t effective_align = align;
if (effective_align < sizeof(void *))
effective_align = sizeof(void *);
bool align_is_valid = (effective_align != 0) &&
((effective_align & (effective_align - 1)) == 0) &&
(effective_align % sizeof(void *) == 0);
if (!align_is_valid)
{
std::stringstream stream;
stream << "Invalid alignment (" << align
<< ") requested for aligned allocation. Alignment must be a power-of-two "
<< "multiple of " << sizeof(void *) << ".";
print_error_and_terminate(stream);
}
// Use posix_memalign instead of aligned_alloc for tcmalloc compatibility.
// posix_memalign is more compatible with tcmalloc and avoids "invalid pointer" errors
// when freeing memory allocated with aligned_alloc and freed with tcmalloc's free().
int ret = posix_memalign(ptr, effective_align, size);
if (ret != 0)
{
*ptr = nullptr;
if (ret == EINVAL)
{
std::stringstream stream;
stream << "posix_memalign failed with EINVAL for alignment " << align
<< " (effective alignment " << effective_align
<< "). Alignment must be a power-of-two multiple of " << sizeof(void *) << ".";
print_error_and_terminate(stream);
}

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report_memory_allocation_failure();
}
#else
*ptr = ::_aligned_malloc(size, align); // note the swapped arguments!
#endif
Expand Down