From 12002c540c9de2342d829c5b073c65cfb4549b35 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 27 Jul 2026 00:08:49 +0200
Subject: kapi: fix driver registry locking

---
 kernel/kapi/devices/driver_registry.stress.cpp | 99 ++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 kernel/kapi/devices/driver_registry.stress.cpp

(limited to 'kernel/kapi/devices/driver_registry.stress.cpp')

diff --git a/kernel/kapi/devices/driver_registry.stress.cpp b/kernel/kapi/devices/driver_registry.stress.cpp
new file mode 100644
index 00000000..9214dc0e
--- /dev/null
+++ b/kernel/kapi/devices/driver_registry.stress.cpp
@@ -0,0 +1,99 @@
+#include <kapi/devices.hpp>
+
+#include <kstd/format.hpp>
+#include <kstd/memory.hpp>
+#include <kstd/result.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstdint>
+#include <string_view>
+#include <thread>
+#include <tuple>
+#include <vector>
+
+namespace
+{
+  struct test_protocol final : kapi::devices::bus_protocol
+  {
+    auto enumerate(kapi::devices::bus &) -> void override {}
+
+    [[nodiscard]] auto match(kapi::devices::device const &, kapi::devices::driver const &) const
+        -> kstd::result<std::uint32_t> override
+    {
+      return 0u;
+    }
+  } constinit test_protocol_instance{};
+
+  struct test_device final : kapi::devices::device
+  {
+    using kapi::devices::device::device;
+  };
+
+  struct test_driver final : kapi::devices::driver
+  {
+    [[nodiscard]] auto probe(kapi::devices::device &) -> kstd::result<void> override
+    {
+      return kstd::success();
+    }
+
+    auto unbind(kapi::devices::device &) -> void override {}
+
+    [[nodiscard]] auto name() const noexcept -> std::string_view override
+    {
+      return "driver_registry_stress_test_driver";
+    }
+  };
+
+}  // namespace
+
+constexpr auto driver_thread_count = 4;
+constexpr auto device_thread_count = 4;
+constexpr auto drivers_per_thread = 100;
+constexpr auto devices_per_thread = 200;
+
+SCENARIO("Concurrent driver registration and device attachment is race-free")
+{
+  GIVEN("A bus using a protocol that matches every device, shared by several threads")
+  {
+    auto shared_bus = kstd::make_shared<kapi::devices::bus>("driver_registry_stress_test_bus", test_protocol_instance);
+    kapi::devices::get_root_bus()->add_child(shared_bus);
+
+    WHEN("some threads concurrently register new drivers while others attach and detach devices")
+    {
+      auto threads = std::vector<std::jthread>{};
+      threads.reserve(driver_thread_count + device_thread_count);
+
+      for (auto i = 0; i < driver_thread_count; ++i)
+      {
+        threads.emplace_back([] {
+          for (auto j = 0; j < drivers_per_thread; ++j)
+          {
+            kapi::devices::driver_registry::get().add(kstd::make_shared<test_driver>());
+          }
+        });
+      }
+
+      for (auto thread_index = 0; thread_index < device_thread_count; ++thread_index)
+      {
+        threads.emplace_back([&shared_bus, thread_index] {
+          for (auto i = 0; i < devices_per_thread; ++i)
+          {
+            auto name = kstd::format("driver_registry_stress_test_device_{}_{}", thread_index, i);
+            auto device = kstd::make_shared<test_device>(name);
+
+            shared_bus->add_child(device);
+            std::ignore = shared_bus->remove_child(*device);
+          }
+        });
+      }
+
+      threads.clear();
+
+      THEN("nothing crashed or deadlocked")
+      {
+        SUCCEED();
+      }
+    }
+  }
+}
-- 
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