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Fix bug setting CHERI bounds in address_space_core.h.

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When splitting a power of two aligned chunk into two we need to set
bounds on both halves and not just the top half.
This commit is contained in:
Robert Norton
2022-02-07 17:07:09 +00:00
committed by Matthew Parkinson
parent 539937336d
commit 20ddf8a150
1 changed files with 22 additions and 20 deletions
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42
src/backend/address_space_core.h
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@@ -169,28 +169,30 @@ namespace snmalloc
// Look for larger block and split up recursively
capptr::Chunk<void> bigger =
remove_block<PAL, Pagemap>(local_state, align_bits + 1);
if (bigger != nullptr)
if (SNMALLOC_UNLIKELY(bigger == nullptr))
return nullptr;
// This block is going to be broken up into sub CHUNK_SIZE blocks
// so we need to commit it to enable the next pointers to be used
// inside the block.
if ((align_bits + 1) == MIN_CHUNK_BITS)
{
// This block is going to be broken up into sub CHUNK_SIZE blocks
// so we need to commit it to enable the next pointers to be used
// inside the block.
if ((align_bits + 1) == MIN_CHUNK_BITS)
{
commit_block<PAL>(bigger, MIN_CHUNK_SIZE);
}
size_t left_over_size = bits::one_at_bit(align_bits);
auto left_over = pointer_offset(bigger, left_over_size);
add_block<PAL, Pagemap>(
local_state,
align_bits,
Aal::capptr_bound<FreeChunk, capptr::bounds::Chunk>(
left_over, left_over_size));
check_block(left_over.as_static<FreeChunk>(), align_bits);
commit_block<PAL>(bigger, MIN_CHUNK_SIZE);
}
check_block(bigger.as_static<FreeChunk>(), align_bits + 1);
return bigger;
size_t half_bigger_size = bits::one_at_bit(align_bits);
auto left_over = pointer_offset(bigger, half_bigger_size);
add_block<PAL, Pagemap>(
local_state,
align_bits,
Aal::capptr_bound<FreeChunk, capptr::bounds::Chunk>(
left_over, half_bigger_size));
check_block(left_over.as_static<FreeChunk>(), align_bits);
check_block(bigger.as_static<FreeChunk>(), align_bits);
return Aal::capptr_bound<void, capptr::bounds::Chunk>(
bigger, half_bigger_size);
}
check_block(first, align_bits);