Kernel: Return ENOMEM in more places

There are plenty of places in the kernel that aren't
checking if they actually got their allocation.

This fixes some of them, but definitely not all.

Fixes #3390
Fixes #3391

Also, let's make find_one_free_page() return nullptr
if it doesn't get a free index. This stops the kernel
crashing when out of memory and allows memory purging
to take place again.

Fixes #3487

1 files changed, 2 insertions, 1 deletions

diff --git a/Kernel/VM/PhysicalRegion.cpp b/Kernel/VM/PhysicalRegion.cpp
index 085d33a01a..84f1e765b0 100644
--- a/Kernel/VM/PhysicalRegion.cpp
+++ b/Kernel/VM/PhysicalRegion.cpp
@@ -105,7 +105,8 @@ Optional<unsigned> PhysicalRegion::find_one_free_page()
         return {};
     }
     auto free_index = m_bitmap.find_one_anywhere_unset(m_free_hint);
-    ASSERT(free_index.has_value());
+    if (!free_index.has_value())
+        return {};
   
     auto page_index = free_index.value();
     m_bitmap.set(page_index, true);