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Kernel/SMP: Always take PageDirectory lock before the MemoryManager lock

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This prevents deadlocking due to inconsistent acquisition order.
This commit is contained in:
Andreas Kling 2021-08-09 01:26:02 +02:00
parent d21b8f9013
commit 00bbbdeda6
2 changed files with 9 additions and 10 deletions
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4
Kernel/Memory/Region.cpp
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@ -236,10 +236,10 @@ bool Region::remap_vmobject_page(size_t page_index, bool with_flush)
void Region::unmap(ShouldDeallocateVirtualRange deallocate_range)
{
ScopedSpinLock lock(s_mm_lock);
if (!m_page_directory)
return;
ScopedSpinLock page_lock(m_page_directory->get_lock());
ScopedSpinLock lock(s_mm_lock);
size_t count = page_count();
for (size_t i = 0; i < count; ++i) {
auto vaddr = vaddr_from_page_index(i);
@ -261,8 +261,8 @@ void Region::set_page_directory(PageDirectory& page_directory)
bool Region::map(PageDirectory& page_directory, ShouldFlushTLB should_flush_tlb)
{
ScopedSpinLock lock(s_mm_lock);
ScopedSpinLock page_lock(page_directory.get_lock());
ScopedSpinLock lock(s_mm_lock);
// FIXME: Find a better place for this sanity check(?)
if (is_user() && !is_shared()) {