From f90a022d3a20c86399f49a8154847b73bc1b8fd3 Mon Sep 17 00:00:00 2001
From: Liam <byteslice@airmail.cc>
Date: Tue, 2 Jan 2024 17:12:16 -0500
Subject: kernel: fix debugger and process list lifetime

---
 src/core/debugger/debugger.cpp | 39 +++++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)

(limited to 'src/core/debugger/debugger.cpp')

diff --git a/src/core/debugger/debugger.cpp b/src/core/debugger/debugger.cpp
index 0e270eb50..e86aae846 100644
--- a/src/core/debugger/debugger.cpp
+++ b/src/core/debugger/debugger.cpp
@@ -114,7 +114,7 @@ public:
     }
 
     Kernel::KThread* GetActiveThread() override {
-        return state->active_thread;
+        return state->active_thread.GetPointerUnsafe();
     }
 
 private:
@@ -147,11 +147,14 @@ private:
 
         std::scoped_lock lk{connection_lock};
 
+        // Find the process we are going to debug.
+        SetDebugProcess();
+
         // Ensure everything is stopped.
         PauseEmulation();
 
         // Set up the new frontend.
-        frontend = std::make_unique<GDBStub>(*this, system);
+        frontend = std::make_unique<GDBStub>(*this, system, debug_process.GetPointerUnsafe());
 
         // Set the new state. This will tear down any existing state.
         state = ConnectionState{
@@ -194,15 +197,20 @@ private:
             UpdateActiveThread();
 
             if (state->info.type == SignalType::Watchpoint) {
-                frontend->Watchpoint(state->active_thread, *state->info.watchpoint);
+                frontend->Watchpoint(std::addressof(*state->active_thread),
+                                     *state->info.watchpoint);
             } else {
-                frontend->Stopped(state->active_thread);
+                frontend->Stopped(std::addressof(*state->active_thread));
             }
 
             break;
         case SignalType::ShuttingDown:
             frontend->ShuttingDown();
 
+            // Release members.
+            state->active_thread.Reset(nullptr);
+            debug_process.Reset(nullptr);
+
             // Wait for emulation to shut down gracefully now.
             state->signal_pipe.close();
             state->client_socket.shutdown(boost::asio::socket_base::shutdown_both);
@@ -222,7 +230,7 @@ private:
                 stopped = true;
                 PauseEmulation();
                 UpdateActiveThread();
-                frontend->Stopped(state->active_thread);
+                frontend->Stopped(state->active_thread.GetPointerUnsafe());
                 break;
             }
             case DebuggerAction::Continue:
@@ -232,7 +240,7 @@ private:
                 MarkResumed([&] {
                     state->active_thread->SetStepState(Kernel::StepState::StepPending);
                     state->active_thread->Resume(Kernel::SuspendType::Debug);
-                    ResumeEmulation(state->active_thread);
+                    ResumeEmulation(state->active_thread.GetPointerUnsafe());
                 });
                 break;
             case DebuggerAction::StepThreadLocked: {
@@ -255,6 +263,7 @@ private:
     }
 
     void PauseEmulation() {
+        Kernel::KScopedLightLock ll{debug_process->GetListLock()};
         Kernel::KScopedSchedulerLock sl{system.Kernel()};
 
         // Put all threads to sleep on next scheduler round.
@@ -264,6 +273,9 @@ private:
     }
 
     void ResumeEmulation(Kernel::KThread* except = nullptr) {
+        Kernel::KScopedLightLock ll{debug_process->GetListLock()};
+        Kernel::KScopedSchedulerLock sl{system.Kernel()};
+
         // Wake up all threads.
         for (auto& thread : ThreadList()) {
             if (std::addressof(thread) == except) {
@@ -277,15 +289,16 @@ private:
 
     template <typename Callback>
     void MarkResumed(Callback&& cb) {
-        Kernel::KScopedSchedulerLock sl{system.Kernel()};
         stopped = false;
         cb();
     }
 
     void UpdateActiveThread() {
+        Kernel::KScopedLightLock ll{debug_process->GetListLock()};
+
         auto& threads{ThreadList()};
         for (auto& thread : threads) {
-            if (std::addressof(thread) == state->active_thread) {
+            if (std::addressof(thread) == state->active_thread.GetPointerUnsafe()) {
                 // Thread is still alive, no need to update.
                 return;
             }
@@ -293,12 +306,18 @@ private:
         state->active_thread = std::addressof(threads.front());
     }
 
+private:
+    void SetDebugProcess() {
+        debug_process = std::move(system.Kernel().GetProcessList().back());
+    }
+
     Kernel::KProcess::ThreadList& ThreadList() {
-        return system.ApplicationProcess()->GetThreadList();
+        return debug_process->GetThreadList();
     }
 
 private:
     System& system;
+    Kernel::KScopedAutoObject<Kernel::KProcess> debug_process;
     std::unique_ptr<DebuggerFrontend> frontend;
 
     boost::asio::io_context io_context;
@@ -310,7 +329,7 @@ private:
         boost::process::async_pipe signal_pipe;
 
         SignalInfo info;
-        Kernel::KThread* active_thread;
+        Kernel::KScopedAutoObject<Kernel::KThread> active_thread;
         std::array<u8, 4096> client_data;
         bool pipe_data;
     };
-- 
cgit v1.2.3