Kernel: Add locks around RangeAllocator

We need to keep multiple processors from changing it at the same time.
fleximus · Nov 11, 2020 · 2b25a89 · 2b25a89
1 parent 66f46d0
commit 2b25a89
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Showing 2 changed files with 10 additions and 0 deletions.
diff --git a/Kernel/VM/RangeAllocator.cpp b/Kernel/VM/RangeAllocator.cpp
@@ -44,12 +44,14 @@ void RangeAllocator::initialize_with_range(VirtualAddress base, size_t size)
  m_total_range = { base, size };
  m_available_ranges.append({ base, size });
 #ifdef VRA_DEBUG
+ ScopedSpinLock lock(m_lock);
  dump();
 #endif
 }
 
 void RangeAllocator::initialize_from_parent(const RangeAllocator& parent_allocator)
 {
+ ScopedSpinLock lock(parent_allocator.m_lock);
  m_total_range = parent_allocator.m_total_range;
  m_available_ranges = parent_allocator.m_available_ranges;
 }
@@ -60,6 +62,7 @@ RangeAllocator::~RangeAllocator()
 
 void RangeAllocator::dump() const
 {
+ ASSERT(m_lock.is_locked());
  dbg() << "RangeAllocator{" << this << "}";
  for (auto& range : m_available_ranges) {
  dbg() << " " << String::format("%x", range.base().get()) << " -> " << String::format("%x", range.end().get() - 1);
@@ -85,6 +88,7 @@ Vector<Range, 2> Range::carve(const Range& taken)
 
 void RangeAllocator::carve_at_index(int index, const Range& range)
 {
+ ASSERT(m_lock.is_locked());
  auto remaining_parts = m_available_ranges[index].carve(range);
  ASSERT(remaining_parts.size() >= 1);
  m_available_ranges[index] = remaining_parts[0];
@@ -106,6 +110,7 @@ Range RangeAllocator::allocate_anywhere(size_t size, size_t alignment)
  size_t offset_from_effective_base = 0;
 #endif
 
+ ScopedSpinLock lock(m_lock);
  for (size_t i = 0; i < m_available_ranges.size(); ++i) {
  auto& available_range = m_available_ranges[i];
  // FIXME: This check is probably excluding some valid candidates when using a large alignment.
@@ -140,6 +145,7 @@ Range RangeAllocator::allocate_specific(VirtualAddress base, size_t size)
  return {};
 
  Range allocated_range(base, size);
+ ScopedSpinLock lock(m_lock);
  for (size_t i = 0; i < m_available_ranges.size(); ++i) {
  auto& available_range = m_available_ranges[i];
  if (!available_range.contains(base, size))
@@ -161,6 +167,7 @@ Range RangeAllocator::allocate_specific(VirtualAddress base, size_t size)
 
 void RangeAllocator::deallocate(Range range)
 {
+ ScopedSpinLock lock(m_lock);
  ASSERT(m_total_range.contains(range));
  ASSERT(range.size());
  ASSERT(range.base() < range.end());

diff --git a/Kernel/VM/RangeAllocator.h b/Kernel/VM/RangeAllocator.h
@@ -29,6 +29,7 @@
 #include <AK/String.h>
 #include <AK/Traits.h>
 #include <AK/Vector.h>
+#include <Kernel/SpinLock.h>
 #include <Kernel/VirtualAddress.h>
 
 namespace Kernel {
@@ -92,6 +93,7 @@ class RangeAllocator {
 
  bool contains(const Range& range) const
  {
+ ScopedSpinLock lock(m_lock);
  return m_total_range.contains(range);
  }
 
@@ -100,6 +102,7 @@ class RangeAllocator {
 
  Vector<Range> m_available_ranges;
  Range m_total_range;
+ mutable SpinLock<u8> m_lock;
 };
 
 inline const LogStream& operator<<(const LogStream& stream, const Range& value)