From 85ea66932e0ae3e5dce36aa001d3f363218344ad Mon Sep 17 00:00:00 2001
From: Daniel Bertalan <dani@danielbertalan.dev>
Date: Fri, 13 Aug 2021 12:42:02 +0200
Subject: [PATCH] Kernel: Allow `kfree_aligned` to be called on null pointers

The C++ standard specifies that `free` and `operator delete` should
be callable with nullptr. The non-aligned `kfree` already handles this,
but because of the pointer arithmetic to obtain the allocation start
pointer, the aligned version would produce undefined behavior.
---
 Kernel/Heap/kmalloc.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Kernel/Heap/kmalloc.h b/Kernel/Heap/kmalloc.h
index f7af78577b..5aa0e21a31 100644
--- a/Kernel/Heap/kmalloc.h
+++ b/Kernel/Heap/kmalloc.h
@@ -93,6 +93,8 @@ template<size_t ALIGNMENT>
 
 inline void kfree_aligned(void* ptr)
 {
+    if (ptr == nullptr)
+        return;
     kfree((u8*)ptr - ((const ptrdiff_t*)ptr)[-1]);
 }