kernel: fix page leak on process termination

src/common/page_table.cpp

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "common/page_table.h"
+#include "common/scope_exit.h"
 
 namespace Common {
 
@@ -11,29 +12,10 @@ PageTable::~PageTable() noexcept = default;
 
 bool PageTable::BeginTraversal(TraversalEntry* out_entry, TraversalContext* out_context,
                                Common::ProcessAddress address) const {
-    // Setup invalid defaults.
-    out_entry->phys_addr = 0;
-    out_entry->block_size = page_size;
-    out_context->next_page = 0;
-
-    // Validate that we can read the actual entry.
-    const auto page = address / page_size;
-    if (page >= backing_addr.size()) {
-        return false;
-    }
-
-    // Validate that the entry is mapped.
-    const auto phys_addr = backing_addr[page];
-    if (phys_addr == 0) {
-        return false;
-    }
+    out_context->next_offset = GetInteger(address);
+    out_context->next_page = address / page_size;
 
-    // Populate the results.
-    out_entry->phys_addr = phys_addr + GetInteger(address);
-    out_context->next_page = page + 1;
-    out_context->next_offset = GetInteger(address) + page_size;
-
-    return true;
+    return this->ContinueTraversal(out_entry, out_context);
 }
 
 bool PageTable::ContinueTraversal(TraversalEntry* out_entry, TraversalContext* context) const {
@@ -41,6 +23,12 @@ bool PageTable::ContinueTraversal(TraversalEntry* out_entry, TraversalContext* c
     out_entry->phys_addr = 0;
     out_entry->block_size = page_size;
 
+    // Regardless of whether the page was mapped, advance on exit.
+    SCOPE_EXIT({
+        context->next_page += 1;
+        context->next_offset += page_size;
+    });
+
     // Validate that we can read the actual entry.
     const auto page = context->next_page;
     if (page >= backing_addr.size()) {
@@ -55,8 +43,6 @@ bool PageTable::ContinueTraversal(TraversalEntry* out_entry, TraversalContext* c
 
     // Populate the results.
     out_entry->phys_addr = phys_addr + context->next_offset;
-    context->next_page = page + 1;
-    context->next_offset += page_size;
 
     return true;
 }

src/core/hle/kernel/k_page_table_base.cpp

@@ -431,9 +431,82 @@ Result KPageTableBase::InitializeForProcess(Svc::CreateProcessFlag as_type, bool
                                                m_memory_block_slab_manager));
 }
 
+Result KPageTableBase::FinalizeProcess() {
+    // Only process tables should be finalized.
+    ASSERT(!this->IsKernel());
+
+    // HLE processes don't have memory mapped.
+    R_SUCCEED_IF(m_impl == nullptr);
+
+    // NOTE: Here Nintendo calls an unknown OnFinalize function.
+    // this->OnFinalize();
+
+    // NOTE: Here Nintendo calls a second unknown OnFinalize function.
+    // this->OnFinalize2();
+
+    // Get implementation objects.
+    auto& impl = this->GetImpl();
+    auto& mm = m_kernel.MemoryManager();
+
+    // Traverse, freeing all pages.
+    {
+        // Get the address space size.
+        const size_t as_size = this->GetAddressSpaceSize();
+
+        // Begin the traversal.
+        TraversalContext context;
+        TraversalEntry cur_entry = {
+            .phys_addr = 0,
+            .block_size = 0,
+        };
+
+        bool cur_valid = false;
+        TraversalEntry next_entry;
+        bool next_valid;
+        size_t tot_size = 0;
+
+        next_valid = impl.BeginTraversal(std::addressof(next_entry), std::addressof(context),
+                                         this->GetAddressSpaceStart());
+
+        // Iterate over entries.
+        while (true) {
+            if ((!next_valid && !cur_valid) ||
+                (next_valid && cur_valid &&
+                 next_entry.phys_addr == cur_entry.phys_addr + cur_entry.block_size)) {
+                cur_entry.block_size += next_entry.block_size;
+            } else {
+                if (cur_valid && IsHeapPhysicalAddressForFinalize(cur_entry.phys_addr)) {
+                    mm.Close(cur_entry.phys_addr, cur_entry.block_size / PageSize);
+                }
+
+                // Update tracking variables.
+                tot_size += cur_entry.block_size;
+                cur_entry = next_entry;
+                cur_valid = next_valid;
+            }
+
+            if (cur_entry.block_size + tot_size >= as_size) {
+                break;
+            }
+
+            next_valid =
+                impl.ContinueTraversal(std::addressof(next_entry), std::addressof(context));
+        }
+
+        // Handle the last block.
+        if (cur_valid && IsHeapPhysicalAddressForFinalize(cur_entry.phys_addr)) {
+            mm.Close(cur_entry.phys_addr, cur_entry.block_size / PageSize);
+        }
+    }
+
+    R_SUCCEED();
+}
+
 void KPageTableBase::Finalize() {
+    this->FinalizeProcess();
+
     auto HostUnmapCallback = [&](KProcessAddress addr, u64 size) {
-        if (Settings::IsFastmemEnabled()) {
+        if (m_impl->fastmem_arena) {
             m_system.DeviceMemory().buffer.Unmap(GetInteger(addr), size, false);
         }
     };

src/core/hle/kernel/k_page_table_base.h

@@ -241,6 +241,7 @@ public:
                                 KResourceLimit* resource_limit, Core::Memory::Memory& memory,
                                 KProcessAddress aslr_space_start);
 
+    Result FinalizeProcess();
     void Finalize();
 
     bool IsKernel() const {

src/core/hle/kernel/k_process.cpp

@@ -171,6 +171,12 @@ void KProcess::Finalize() {
         m_resource_limit->Close();
     }
 
+    // Clear expensive resources, as the destructor is not called for guest objects.
+    for (auto& interface : m_arm_interfaces) {
+        interface.reset();
+    }
+    m_exclusive_monitor.reset();
+
     // Perform inherited finalization.
     KSynchronizationObject::Finalize();
 }