Kernel: Make ContiguousVMObject factory API OOM safe

3 files changed, 14 insertions, 8 deletions

diff --git a/Kernel/VM/ContiguousVMObject.cpp b/Kernel/VM/ContiguousVMObject.cpp
index 2550cec829..312c9bd671 100644
--- a/Kernel/VM/ContiguousVMObject.cpp
+++ b/Kernel/VM/ContiguousVMObject.cpp
@@ -10,15 +10,17 @@
 
 namespace Kernel {
 
-NonnullRefPtr<ContiguousVMObject> ContiguousVMObject::create_with_size(size_t size, size_t physical_alignment)
+RefPtr<ContiguousVMObject> ContiguousVMObject::create_with_size(size_t size, size_t physical_alignment)
 {
-    return adopt_ref(*new ContiguousVMObject(size, physical_alignment));
+    auto contiguous_physical_pages = MM.allocate_contiguous_supervisor_physical_pages(size, physical_alignment);
+    if (contiguous_physical_pages.is_empty())
+        return {};
+    return adopt_ref_if_nonnull(new ContiguousVMObject(size, contiguous_physical_pages));
 }
 
-ContiguousVMObject::ContiguousVMObject(size_t size, size_t physical_alignment)
+ContiguousVMObject::ContiguousVMObject(size_t size, NonnullRefPtrVector<PhysicalPage>& contiguous_physical_pages)
     : VMObject(size)
 {
-    auto contiguous_physical_pages = MM.allocate_contiguous_supervisor_physical_pages(size, physical_alignment);
     for (size_t i = 0; i < page_count(); i++) {
         physical_pages()[i] = contiguous_physical_pages[i];
         dbgln_if(CONTIGUOUS_VMOBJECT_DEBUG, "Contiguous page[{}]: {}", i, physical_pages()[i]->paddr());
diff --git a/Kernel/VM/ContiguousVMObject.h b/Kernel/VM/ContiguousVMObject.h
index 576fa696cd..c6c25ca7df 100644
--- a/Kernel/VM/ContiguousVMObject.h
+++ b/Kernel/VM/ContiguousVMObject.h
@@ -7,18 +7,18 @@
 #pragma once
 
 #include <Kernel/PhysicalAddress.h>
+#include <Kernel/VM/MemoryManager.h>
 #include <Kernel/VM/VMObject.h>
 
 namespace Kernel {
-
 class ContiguousVMObject final : public VMObject {
 public:
     virtual ~ContiguousVMObject() override;
 
-    static NonnullRefPtr<ContiguousVMObject> create_with_size(size_t, size_t physical_alignment = PAGE_SIZE);
+    static RefPtr<ContiguousVMObject> create_with_size(size_t, size_t physical_alignment = PAGE_SIZE);
 
 private:
-    explicit ContiguousVMObject(size_t, size_t physical_alignment);
+    explicit ContiguousVMObject(size_t, NonnullRefPtrVector<PhysicalPage>&);
     explicit ContiguousVMObject(const ContiguousVMObject&);
 
     virtual const char* class_name() const override { return "ContiguousVMObject"; }
diff --git a/Kernel/VM/MemoryManager.cpp b/Kernel/VM/MemoryManager.cpp
index 0c24693355..33b7be6c76 100644
--- a/Kernel/VM/MemoryManager.cpp
+++ b/Kernel/VM/MemoryManager.cpp
@@ -464,7 +464,11 @@ OwnPtr<Region> MemoryManager::allocate_contiguous_kernel_region(size_t size, Str
     if (!range.has_value())
         return {};
     auto vmobject = ContiguousVMObject::create_with_size(size, physical_alignment);
-    return allocate_kernel_region_with_vmobject(range.value(), vmobject, name, access, cacheable);
+    if (!vmobject) {
+        kernel_page_directory().range_allocator().deallocate(range.value());
+        return {};
+    }
+    return allocate_kernel_region_with_vmobject(range.value(), *vmobject, name, access, cacheable);
 }
 
 OwnPtr<Region> MemoryManager::allocate_kernel_region(size_t size, StringView name, Region::Access access, AllocationStrategy strategy, Region::Cacheable cacheable)