Fix VMO leak in Process::exec().

Gotta make sure things get cleaned up before we yield-teleport in exec().
Also VMOs and regions are now viewable through /proc/mm and /proc/regions.

Kernel/MemoryManager.cpp

@@ -619,6 +619,8 @@ Region::Region(LinearAddress a, size_t s, String&& n, bool r, bool w, bool cow)
     , is_writable(w)
     , cow_map(Bitmap::create(m_vmo->page_count(), cow))
 {
+    m_vmo->set_name(name);
+    MM.register_region(*this);
 }
 
 Region::Region(LinearAddress a, size_t s, RetainPtr<VirtualFileSystem::Node>&& vnode, String&& n, bool r, bool w)
@@ -630,6 +632,7 @@ Region::Region(LinearAddress a, size_t s, RetainPtr<VirtualFileSystem::Node>&& v
     , is_writable(w)
     , cow_map(Bitmap::create(m_vmo->page_count()))
 {
+    MM.register_region(*this);
 }
 
 Region::Region(LinearAddress a, size_t s, RetainPtr<VMObject>&& vmo, size_t offset_in_vmo, String&& n, bool r, bool w, bool cow)
@@ -642,10 +645,12 @@ Region::Region(LinearAddress a, size_t s, RetainPtr<VMObject>&& vmo, size_t offs
     , is_writable(w)
     , cow_map(Bitmap::create(m_vmo->page_count(), cow))
 {
+    MM.register_region(*this);
 }
 
 Region::~Region()
 {
+    MM.unregister_region(*this);
 }
 
 void PhysicalPage::return_to_freelist()
@@ -738,10 +743,24 @@ int Region::commit(Process& process)
 
 void MemoryManager::register_vmo(VMObject& vmo)
 {
+    InterruptDisabler disabler;
     m_vmos.set(&vmo);
 }
 
 void MemoryManager::unregister_vmo(VMObject& vmo)
 {
+    InterruptDisabler disabler;
     m_vmos.remove(&vmo);
 }
+
+void MemoryManager::register_region(Region& region)
+{
+    InterruptDisabler disabler;
+    m_regions.set(&region);
+}
+
+void MemoryManager::unregister_region(Region& region)
+{
+    InterruptDisabler disabler;
+    m_regions.remove(&region);
+}

Kernel/MemoryManager.h

@@ -146,6 +146,7 @@ class MemoryManager {
     friend class Region;
     friend class VMObject;
     friend ByteBuffer procfs$mm();
+    friend ByteBuffer procfs$regions();
 public:
     static MemoryManager& the() PURE;
 
@@ -181,6 +182,8 @@ private:
 
     void register_vmo(VMObject&);
     void unregister_vmo(VMObject&);
+    void register_region(Region&);
+    void unregister_region(Region&);
 
     LinearAddress allocate_linear_address_range(size_t);
     void map_region_at_address(PageDirectory*, Region&, LinearAddress, bool user_accessible);
@@ -296,6 +299,7 @@ private:
     Vector<RetainPtr<PhysicalPage>> m_free_physical_pages;
 
     HashTable<VMObject*> m_vmos;
+    HashTable<Region*> m_regions;
 };
 
 struct KernelPagingScope {

Kernel/ProcFileSystem.cpp

@@ -171,7 +171,12 @@ ByteBuffer procfs$mm()
     auto buffer = ByteBuffer::createUninitialized(1024 + 80 * MM.m_vmos.size());
     char* ptr = (char*)buffer.pointer();
     for (auto* vmo : MM.m_vmos) {
-        ptr += ksprintf(ptr, "VMO: %p %s (p:%u, r:%u)\n", vmo, vmo->name().characters(), vmo->page_count(), vmo->retainCount());
+        ptr += ksprintf(ptr, "VMO: %p %s(%u): p:%4u %s\n",
+            vmo,
+            vmo->is_anonymous() ? "anon" : "file",
+            vmo->retainCount(),
+            vmo->page_count(),
+            vmo->name().characters());
     }
     ptr += ksprintf(ptr, "VMO count: %u\n", MM.m_vmos.size());
     ptr += ksprintf(ptr, "Free physical pages: %u\n", MM.m_free_physical_pages.size());
@@ -179,6 +184,22 @@ ByteBuffer procfs$mm()
     return buffer;
 }
 
+ByteBuffer procfs$regions()
+{
+    // FIXME: Implement
+    InterruptDisabler disabler;
+    auto buffer = ByteBuffer::createUninitialized(1024 + 80 * MM.m_regions.size());
+    char* ptr = (char*)buffer.pointer();
+    for (auto* region : MM.m_regions) {
+        ptr += ksprintf(ptr, "Region: %p VMO=%p %s\n",
+            region,
+            &region->vmo(),
+            region->name.characters());
+    }
+    ptr += ksprintf(ptr, "Region count: %u\n", MM.m_regions.size());
+    buffer.trim(ptr - (char*)buffer.pointer());
+    return buffer;
+}
 
 ByteBuffer procfs$mounts()
 {
@@ -302,6 +323,7 @@ bool ProcFileSystem::initialize()
 {
     SyntheticFileSystem::initialize();
     addFile(createGeneratedFile("mm", procfs$mm));
+    addFile(createGeneratedFile("regions", procfs$regions));
     addFile(createGeneratedFile("mounts", procfs$mounts));
     addFile(createGeneratedFile("kmalloc", procfs$kmalloc));
     addFile(createGeneratedFile("summary", procfs$summary));

Kernel/Process.cpp

@@ -307,15 +307,11 @@ int Process::exec(const String& path, Vector<String>&& arguments, Vector<String>
         return -ENOTIMPL;
     }
 
+    { // Put everything into a scope so things get cleaned up before we yield-teleport into the new executable.
     auto vmo = VMObject::create_file_backed(descriptor->vnode(), descriptor->metadata().size);
+    vmo->set_name(descriptor->absolute_path());
     auto* region = allocate_region_with_vmo(LinearAddress(), descriptor->metadata().size, vmo.copyRef(), 0, "helper", true, false);
 
-#if 0
-    auto elfData = descriptor->readEntireFile();
-    if (!elfData)
-        return -EIO; // FIXME: Get a more detailed error from VFS.
-#endif
-
     dword entry_eip = 0;
     PageDirectory* old_page_directory = m_page_directory;
     PageDirectory* new_page_directory = reinterpret_cast<PageDirectory*>(kmalloc_page_aligned(sizeof(PageDirectory)));
@@ -324,6 +320,7 @@ int Process::exec(const String& path, Vector<String>&& arguments, Vector<String>
     m_page_directory = new_page_directory;
     MM.enter_process_paging_scope(*this);
 
+    // FIXME: Should we consider doing on-demand paging here? Is it actually useful?
     bool success = region->page_in(*new_page_directory);
 
     ASSERT(success);
@@ -400,10 +397,11 @@ int Process::exec(const String& path, Vector<String>&& arguments, Vector<String>
 #endif
 
     set_state(Skip1SchedulerPass);
+    } // Ready to yield-teleport!
 
     if (current == this) {
         bool success = Scheduler::yield();
-        ASSERT(success);
+        ASSERT_NOT_REACHED();
     }
 
     return 0;