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LibJS: Add some basic freelist validation for the GC heap

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When using the freelist, we now validate that the entries are actual
cell pointers within the current HeapBlock.
This commit is contained in:
Andreas Kling 2021-02-13 00:17:28 +01:00
parent 46e5890152
commit e1dbf74f15
2 changed files with 8 additions and 0 deletions
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2
Userland/Libraries/LibJS/Heap/HeapBlock.cpp
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@ -75,6 +75,8 @@ HeapBlock::HeapBlock(Heap& heap, size_t cell_size)
void HeapBlock::deallocate(Cell* cell) void HeapBlock::deallocate(Cell* cell)
{ {
ASSERT(is_valid_cell_pointer(cell));
ASSERT(!m_freelist || is_valid_cell_pointer(m_freelist));
ASSERT(cell->is_live()); ASSERT(cell->is_live());
ASSERT(!cell->is_marked()); ASSERT(!cell->is_marked());
cell->~Cell(); cell->~Cell();

6
Userland/Libraries/LibJS/Heap/HeapBlock.h
View file

@ -51,6 +51,7 @@ public:
{ {
if (!m_freelist) if (!m_freelist)
return nullptr; return nullptr;
ASSERT(is_valid_cell_pointer(m_freelist));
return exchange(m_freelist, m_freelist->next); return exchange(m_freelist, m_freelist->next);
} }
@ -80,6 +81,11 @@ public:
return cell(cell_index); return cell(cell_index);
} }
bool is_valid_cell_pointer(const Cell* cell)
{
return cell_from_possible_pointer((FlatPtr)cell);
}
IntrusiveListNode m_list_node; IntrusiveListNode m_list_node;
private: private: