4 files changed, 19 insertions, 0 deletions
diff --git a/Kernel/VM/MemoryManager.cpp b/Kernel/VM/MemoryManager.cpp
index 885cdbd19f..dcfb041828 100644
--- a/Kernel/VM/MemoryManager.cpp
+++ b/Kernel/VM/MemoryManager.cpp
@@ -549,6 +549,12 @@ void MemoryManager::unquickmap_page()
     m_quickmap_in_use = false;
 }
 
+bool MemoryManager::validate_user_stack(const Process& process, VirtualAddress vaddr) const
+{
+    auto* region = region_from_vaddr(process, vaddr);
+    return region && region->is_stack();
+}
+
 bool MemoryManager::validate_user_read(const Process& process, VirtualAddress vaddr) const
 {
     auto* region = region_from_vaddr(process, vaddr);
diff --git a/Kernel/VM/MemoryManager.h b/Kernel/VM/MemoryManager.h
index 399d0f1502..619f95630c 100644
--- a/Kernel/VM/MemoryManager.h
+++ b/Kernel/VM/MemoryManager.h
@@ -46,6 +46,7 @@ public:
 
     void enter_process_paging_scope(Process&);
 
+    bool validate_user_stack(const Process&, VirtualAddress) const;
     bool validate_user_read(const Process&, VirtualAddress) const;
     bool validate_user_write(const Process&, VirtualAddress) const;
 
diff --git a/Kernel/VM/Region.cpp b/Kernel/VM/Region.cpp
index 65495779d3..7104dd1534 100644
--- a/Kernel/VM/Region.cpp
+++ b/Kernel/VM/Region.cpp
@@ -58,6 +58,7 @@ NonnullOwnPtr<Region> Region::clone()
     ASSERT(is_user_accessible());
 
     if (m_shared || (is_readable() && !is_writable())) {
+        ASSERT(!m_stack);
 #ifdef MM_DEBUG
         dbgprintf("%s<%u> Region::clone(): sharing %s (V%p)\n",
             current->process().name().characters(),
@@ -81,6 +82,13 @@ NonnullOwnPtr<Region> Region::clone()
     remap();
     auto clone_region = Region::create_user_accessible(m_range, m_vmobject->clone(), m_offset_in_vmo, m_name, m_access);
     clone_region->ensure_cow_map();
+    if (m_stack) {
+        ASSERT(is_readable());
+        ASSERT(is_writable());
+        ASSERT(!is_shared());
+        ASSERT(vmobject().is_anonymous());
+        clone_region->set_stack(true);
+    }
     return clone_region;
 }
 
diff --git a/Kernel/VM/Region.h b/Kernel/VM/Region.h
index 50ea87ff04..5501e6b2e3 100644
--- a/Kernel/VM/Region.h
+++ b/Kernel/VM/Region.h
@@ -50,6 +50,9 @@ public:
     bool is_shared() const { return m_shared; }
     void set_shared(bool shared) { m_shared = shared; }
 
+    bool is_stack() const { return m_stack; }
+    void set_stack(bool stack) { m_stack = stack; }
+
     bool is_user_accessible() const { return m_user_accessible; }
 
     PageFaultResponse handle_fault(const PageFault&);
@@ -141,5 +144,6 @@ private:
     u8 m_access { 0 };
     bool m_shared { false };
     bool m_user_accessible { false };
+    bool m_stack { false };
     mutable OwnPtr<Bitmap> m_cow_map;
 };