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Kernel: Ensure PhysicalRegion free page hint is within valid range

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Fixes #3770
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Tom 2020-10-16 09:35:23 -06:00 • committed by Andreas Kling
parent b98b83712f
commit 6fbced6f4f
1 changed files with 4 additions and 0 deletions
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4
Kernel/VM/PhysicalRegion.cpp
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@ -112,6 +112,8 @@ Optional<unsigned> PhysicalRegion::find_one_free_page()
m_bitmap.set(page_index, true); m_bitmap.set(page_index, true);
m_used++; m_used++;
m_free_hint = free_index.value() + 1; // Just a guess m_free_hint = free_index.value() + 1; // Just a guess
if (m_free_hint >= m_bitmap.size())
m_free_hint = 0;
return page_index; return page_index;
} }
@ -128,6 +130,8 @@ Optional<unsigned> PhysicalRegion::find_and_allocate_contiguous_range(size_t cou
m_bitmap.set_range<true>(page, count); m_bitmap.set_range<true>(page, count);
m_used += count; m_used += count;
m_free_hint = first_index.value() + count + 1; // Just a guess m_free_hint = first_index.value() + count + 1; // Just a guess
if (m_free_hint >= m_bitmap.size())
m_free_hint = 0;
return page; return page;
} }
return {}; return {};