Kernel: Make Thread refcounted

Similar to Process, we need to make Thread refcounted. This will solve
problems that will appear once we schedule threads on more than one
processor. This allows us to hold onto threads without necessarily
holding the scheduler lock for the entire duration.

1 files changed, 8 insertions, 3 deletions

diff --git a/Kernel/init.cpp b/Kernel/init.cpp
index c0d317b915..7a6751a32a 100644
--- a/Kernel/init.cpp
+++ b/Kernel/init.cpp
@@ -168,8 +168,13 @@ extern "C" [[noreturn]] void init()
     Process::initialize();
     Scheduler::initialize();
 
-    Thread* init_stage2_thread = nullptr;
-    Process::create_kernel_process(init_stage2_thread, "init_stage2", init_stage2);
+    {
+        RefPtr<Thread> init_stage2_thread;
+        Process::create_kernel_process(init_stage2_thread, "init_stage2", init_stage2);
+        // We need to make sure we drop the reference for init_stage2_thread
+        // before calling into Scheduler::start, otherwise we will have a
+        // dangling Thread that never gets cleaned up
+    }
 
     Scheduler::start();
     ASSERT_NOT_REACHED();
@@ -351,7 +356,7 @@ void init_stage2()
 
     // FIXME: It would be nicer to set the mode from userspace.
     tty0->set_graphical(!text_mode);
-    Thread* thread = nullptr;
+    RefPtr<Thread> thread;
     auto userspace_init = kernel_command_line().lookup("init").value_or("/bin/SystemServer");
     Process::create_user_process(thread, userspace_init, (uid_t)0, (gid_t)0, ProcessID(0), error, {}, {}, tty0);
     if (error != 0) {