From 4b28e4626e744ac9b779a680f8e9647014956dda Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Sun, 26 Jul 2026 21:46:37 +0200
Subject: kapi/devices: implement locking discipline

---
 kernel/kapi/devices/bus.stress.cpp | 76 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 kernel/kapi/devices/bus.stress.cpp

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

diff --git a/kernel/kapi/devices/bus.stress.cpp b/kernel/kapi/devices/bus.stress.cpp
new file mode 100644
index 00000000..226b0296
--- /dev/null
+++ b/kernel/kapi/devices/bus.stress.cpp
@@ -0,0 +1,76 @@
+#include <kapi/devices.hpp>
+
+#include <kstd/format.hpp>
+#include <kstd/memory.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <atomic>
+#include <cstddef>
+#include <thread>
+#include <tuple>
+#include <vector>
+
+namespace
+{
+
+  struct test_device final : kapi::devices::device
+  {
+    using kapi::devices::device::device;
+  };
+
+}  // namespace
+
+constexpr auto thread_count = 32;
+constexpr auto devices_per_thread = 200;
+
+SCENARIO("Concurrent attach/detach/lookup on a bus is race-free")
+{
+  GIVEN("A bus shared by several threads")
+  {
+    auto shared_bus = kstd::make_shared<kapi::devices::bus>("stress_test_bus");
+    kapi::devices::get_root_bus()->add_child(shared_bus);
+
+    WHEN("each thread repeatedly attaches, detaches, and looks up devices concurrently with the others")
+    {
+      auto threads = std::vector<std::jthread>{};
+      threads.reserve(thread_count);
+
+      auto failure_count = std::atomic<std::size_t>{0};
+
+      for (auto thread_index = 0uz; thread_index < thread_count; ++thread_index)
+      {
+        threads.emplace_back([&shared_bus, &failure_count, thread_index] {
+          for (auto i = 0uz; i < devices_per_thread; ++i)
+          {
+            auto name = kstd::format("stress_test_device_{}_{}", thread_index, i);
+            auto device = kstd::make_shared<test_device>(name);
+
+            shared_bus->add_child(device);
+
+            std::ignore = kapi::devices::device_registry::get().find(name);
+            std::ignore = kapi::devices::device_registry::get().all();
+            std::ignore = shared_bus->children().size();
+
+            if (!shared_bus->remove_child(*device))
+            {
+              ++failure_count;
+            };
+          }
+        });
+      }
+
+      threads.clear();
+
+      THEN("every attach was matched by a successful removal")
+      {
+        REQUIRE(failure_count == 0);
+      }
+
+      THEN("the bus has no children")
+      {
+        REQUIRE(shared_bus->children().empty());
+      }
+    }
+  }
+}
\ No newline at end of file
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