diff --git a/Kernel/Arch/x86/common/PageDirectory.cpp b/Kernel/Arch/x86/common/PageDirectory.cpp
index 993dab67ca..1efe016508 100644
--- a/Kernel/Arch/x86/common/PageDirectory.cpp
+++ b/Kernel/Arch/x86/common/PageDirectory.cpp
@@ -1,43 +1,41 @@
 /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2018-2022, James Mintram <me@jamesrm.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <AK/Singleton.h>
-
-#include <Kernel/Arch/InterruptDisabler.h>
 #include <Kernel/Memory/PageDirectory.h>
 #include <Kernel/Thread.h>
 
 namespace Kernel::Memory {
 
-// FIXME: This needs real locking:
-static Singleton<IntrusiveRedBlackTree<&PageDirectory::m_tree_node>> s_cr3_map;
+struct CR3Map {
+    SpinlockProtected<IntrusiveRedBlackTree<&PageDirectory::m_tree_node>> map { LockRank::None };
+};
 
-static IntrusiveRedBlackTree<&PageDirectory::m_tree_node>& cr3_map()
-{
-    VERIFY_INTERRUPTS_DISABLED();
-    return *s_cr3_map;
-}
+static Singleton<CR3Map> s_cr3_map;
 
 void PageDirectory::register_page_directory(PageDirectory* directory)
 {
-    InterruptDisabler disabler;
-    cr3_map().insert(directory->cr3(), *directory);
+    s_cr3_map->map.with([&](auto& map) {
+        map.insert(directory->cr3(), *directory);
+    });
 }
 
 void PageDirectory::deregister_page_directory(PageDirectory* directory)
 {
-    InterruptDisabler disabler;
-    cr3_map().remove(directory->cr3());
+    s_cr3_map->map.with([&](auto& map) {
+        map.remove(directory->cr3());
+    });
 }
 
 LockRefPtr<PageDirectory> PageDirectory::find_current()
 {
-    SpinlockLocker lock(s_mm_lock);
-    return cr3_map().find(read_cr3());
+    return s_cr3_map->map.with([&](auto& map) {
+        return map.find(read_cr3());
+    });
 }
 
 void activate_kernel_page_directory(PageDirectory const& pgd)