From b014f1cd12262afee9933d7c07d61242edc28a95 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 16 Mar 2026 14:31:52 +0100
Subject: kernel/heap: fix infinite allocation loop

---
 kernel/src/memory/block_list_allocator.cpp | 64 +++++++++++++++---------------
 1 file changed, 31 insertions(+), 33 deletions(-)

diff --git a/kernel/src/memory/block_list_allocator.cpp b/kernel/src/memory/block_list_allocator.cpp
index 1bd17ff..5d870d8 100644
--- a/kernel/src/memory/block_list_allocator.cpp
+++ b/kernel/src/memory/block_list_allocator.cpp
@@ -42,51 +42,49 @@ namespace kernel::memory
       auto current = m_block_list;
       while (current != nullptr)
       {
-        if (!current->free)
+        if (current->free)
         {
-          current = current->next;
-          continue;
-        }
+          auto const raw_block = reinterpret_cast<std::byte *>(current);
+          auto const unaligned_payload = raw_block + allocated_metadata_size;
+          auto const aligned_payload = align_up(unaligned_payload, alignment);
+          auto const required_padding = static_cast<std::size_t>(aligned_payload - unaligned_payload);
+          auto const total_required_size = required_padding + allocated_metadata_size + size;
 
-        auto const raw_block = reinterpret_cast<std::byte *>(current);
-        auto const unaligned_payload = raw_block + allocated_metadata_size;
-        auto const aligned_payload = align_up(unaligned_payload, alignment);
-        auto const required_padding = static_cast<std::size_t>(aligned_payload - unaligned_payload);
-        auto const total_required_size = required_padding + allocated_metadata_size + size;
+          if (current->usable_size >= total_required_size)
+          {
+            auto const payload_header = aligned_payload - sizeof(block_header *) - sizeof(block_header);
+            auto const front_padding = static_cast<std::size_t>(payload_header - raw_block);
 
-        if (current->usable_size >= total_required_size)
-        {
-          auto const payload_header = aligned_payload - sizeof(block_header *) - sizeof(block_header);
-          auto const front_padding = static_cast<std::size_t>(payload_header - raw_block);
+            auto payload_block = current;
 
-          auto payload_block = current;
+            if (front_padding >= allocated_metadata_size + minimum_allocation_size)
+            {
+              payload_block = reinterpret_cast<block_header *>(payload_header);
+              std::construct_at(payload_block, current->usable_size - front_padding, true, current->next);
 
-          if (front_padding >= allocated_metadata_size + minimum_allocation_size)
-          {
-            payload_block = reinterpret_cast<block_header *>(payload_header);
-            std::construct_at(payload_block, current->usable_size - front_padding, true, current->next);
+              if (payload_block->next)
+              {
+                payload_block->next->prev = payload_block;
+              }
 
-            if (payload_block->next)
-            {
-              payload_block->next->prev = payload_block;
+              current->usable_size = front_padding - allocated_metadata_size;
+              current->next = payload_block;
+              payload_block->prev = current;
             }
 
-            current->usable_size = front_padding - allocated_metadata_size;
-            current->next = payload_block;
-            payload_block->prev = current;
-          }
-
-          auto const payload_size =
-              aligned_payload - reinterpret_cast<std::byte *>(payload_block) - allocated_metadata_size + size;
-          split(payload_block, payload_size, 0uz);
+            auto const payload_size =
+                aligned_payload - reinterpret_cast<std::byte *>(payload_block) - allocated_metadata_size + size;
+            split(payload_block, payload_size, 0uz);
 
-          payload_block->free = false;
+            payload_block->free = false;
 
-          auto back_pointer = reinterpret_cast<block_header **>(aligned_payload - sizeof(block_header *));
-          *back_pointer = payload_block;
+            auto back_pointer = reinterpret_cast<block_header **>(aligned_payload - sizeof(block_header *));
+            *back_pointer = payload_block;
 
-          return reinterpret_cast<void *>(aligned_payload);
+            return reinterpret_cast<void *>(aligned_payload);
+          }
         }
+        current = current->next;
       }
 
       auto const search_size = size + static_cast<std::size_t>(alignment);
-- 
cgit v1.2.3