Merge changes Ice773436,Ib8a4835c into rvc-dev

* changes:
  init: handle property messages asynchronously #2
  Revert "init: handle property service callbacks asynchronously"
diff --git a/init/Android.bp b/init/Android.bp
index 52628f3..72a7bfe 100644
--- a/init/Android.bp
+++ b/init/Android.bp
@@ -28,7 +28,6 @@
     "rlimit_parser.cpp",
     "service.cpp",
     "service_list.cpp",
-    "service_lock.cpp",
     "service_parser.cpp",
     "service_utils.cpp",
     "subcontext.cpp",
diff --git a/init/builtins.cpp b/init/builtins.cpp
index dd5af72..200bfff 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -151,7 +151,6 @@
 
 template <typename F>
 static void ForEachServiceInClass(const std::string& classname, F function) {
-    auto lock = std::lock_guard{service_lock};
     for (const auto& service : ServiceList::GetInstance()) {
         if (service->classnames().count(classname)) std::invoke(function, service);
     }
@@ -163,7 +162,6 @@
         return {};
     // Starting a class does not start services which are explicitly disabled.
     // They must  be started individually.
-    auto lock = std::lock_guard{service_lock};
     for (const auto& service : ServiceList::GetInstance()) {
         if (service->classnames().count(args[1])) {
             if (auto result = service->StartIfNotDisabled(); !result.ok()) {
@@ -186,7 +184,6 @@
         // stopped either.
         return {};
     }
-    auto lock = std::lock_guard{service_lock};
     for (const auto& service : ServiceList::GetInstance()) {
         if (service->classnames().count(args[1])) {
             if (auto result = service->StartIfPostData(); !result.ok()) {
@@ -237,7 +234,6 @@
 }
 
 static Result<void> do_enable(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     Service* svc = ServiceList::GetInstance().FindService(args[1]);
     if (!svc) return Error() << "Could not find service";
 
@@ -249,7 +245,6 @@
 }
 
 static Result<void> do_exec(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     auto service = Service::MakeTemporaryOneshotService(args.args);
     if (!service.ok()) {
         return Error() << "Could not create exec service: " << service.error();
@@ -263,7 +258,6 @@
 }
 
 static Result<void> do_exec_background(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     auto service = Service::MakeTemporaryOneshotService(args.args);
     if (!service.ok()) {
         return Error() << "Could not create exec background service: " << service.error();
@@ -277,7 +271,6 @@
 }
 
 static Result<void> do_exec_start(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     Service* service = ServiceList::GetInstance().FindService(args[1]);
     if (!service) {
         return Error() << "Service not found";
@@ -347,7 +340,6 @@
 }
 
 static Result<void> do_interface_restart(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     Service* svc = ServiceList::GetInstance().FindInterface(args[1]);
     if (!svc) return Error() << "interface " << args[1] << " not found";
     svc->Restart();
@@ -355,7 +347,6 @@
 }
 
 static Result<void> do_interface_start(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     Service* svc = ServiceList::GetInstance().FindInterface(args[1]);
     if (!svc) return Error() << "interface " << args[1] << " not found";
     if (auto result = svc->Start(); !result.ok()) {
@@ -365,7 +356,6 @@
 }
 
 static Result<void> do_interface_stop(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     Service* svc = ServiceList::GetInstance().FindInterface(args[1]);
     if (!svc) return Error() << "interface " << args[1] << " not found";
     svc->Stop();
@@ -750,7 +740,6 @@
 }
 
 static Result<void> do_start(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     Service* svc = ServiceList::GetInstance().FindService(args[1]);
     if (!svc) return Error() << "service " << args[1] << " not found";
     if (auto result = svc->Start(); !result.ok()) {
@@ -760,7 +749,6 @@
 }
 
 static Result<void> do_stop(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     Service* svc = ServiceList::GetInstance().FindService(args[1]);
     if (!svc) return Error() << "service " << args[1] << " not found";
     svc->Stop();
@@ -768,7 +756,6 @@
 }
 
 static Result<void> do_restart(const BuiltinArguments& args) {
-    auto lock = std::lock_guard{service_lock};
     Service* svc = ServiceList::GetInstance().FindService(args[1]);
     if (!svc) return Error() << "service " << args[1] << " not found";
     svc->Restart();
@@ -1124,7 +1111,6 @@
             function(StringPrintf("Exec service failed, status %d", siginfo.si_status));
         }
     });
-    auto lock = std::lock_guard{service_lock};
     if (auto result = (*service)->ExecStart(); !result.ok()) {
         function("ExecStart failed: " + result.error().message());
     }
@@ -1264,7 +1250,6 @@
         }
         success &= parser.ParseConfigFile(c);
     }
-    auto lock = std::lock_guard{service_lock};
     ServiceList::GetInstance().MarkServicesUpdate();
     if (success) {
         return {};
diff --git a/init/init.cpp b/init/init.cpp
index b0f929c..b29dfa3 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -99,6 +99,15 @@
 
 static std::unique_ptr<Subcontext> subcontext;
 
+struct PendingControlMessage {
+    std::string message;
+    std::string name;
+    pid_t pid;
+    int fd;
+};
+static std::mutex pending_control_messages_lock;
+static std::queue<PendingControlMessage> pending_control_messages;
+
 // Init epolls various FDs to wait for various inputs.  It previously waited on property changes
 // with a blocking socket that contained the information related to the change, however, it was easy
 // to fill that socket and deadlock the system.  Now we use locks to handle the property changes
@@ -120,7 +129,7 @@
         }
     };
 
-    if (auto result = epoll->RegisterHandler(epoll_fd, drain_socket); !result) {
+    if (auto result = epoll->RegisterHandler(epoll_fd, drain_socket); !result.ok()) {
         LOG(FATAL) << result.error();
     }
 }
@@ -238,7 +247,6 @@
 } shutdown_state;
 
 void DumpState() {
-    auto lock = std::lock_guard{service_lock};
     ServiceList::GetInstance().DumpState();
     ActionManager::GetInstance().DumpState();
 }
@@ -312,7 +320,6 @@
 
 static std::optional<boot_clock::time_point> HandleProcessActions() {
     std::optional<boot_clock::time_point> next_process_action_time;
-    auto lock = std::lock_guard{service_lock};
     for (const auto& s : ServiceList::GetInstance()) {
         if ((s->flags() & SVC_RUNNING) && s->timeout_period()) {
             auto timeout_time = s->time_started() + *s->timeout_period();
@@ -341,7 +348,7 @@
     return next_process_action_time;
 }
 
-static Result<void> DoControlStart(Service* service) REQUIRES(service_lock) {
+static Result<void> DoControlStart(Service* service) {
     return service->Start();
 }
 
@@ -350,7 +357,7 @@
     return {};
 }
 
-static Result<void> DoControlRestart(Service* service) REQUIRES(service_lock) {
+static Result<void> DoControlRestart(Service* service) {
     service->Restart();
     return {};
 }
@@ -384,7 +391,7 @@
     return control_message_functions;
 }
 
-bool HandleControlMessage(const std::string& msg, const std::string& name, pid_t from_pid) {
+bool HandleControlMessage(const std::string& msg, const std::string& name, pid_t pid) {
     const auto& map = get_control_message_map();
     const auto it = map.find(msg);
 
@@ -393,7 +400,7 @@
         return false;
     }
 
-    std::string cmdline_path = StringPrintf("proc/%d/cmdline", from_pid);
+    std::string cmdline_path = StringPrintf("proc/%d/cmdline", pid);
     std::string process_cmdline;
     if (ReadFileToString(cmdline_path, &process_cmdline)) {
         std::replace(process_cmdline.begin(), process_cmdline.end(), '\0', ' ');
@@ -404,8 +411,6 @@
 
     const ControlMessageFunction& function = it->second;
 
-    auto lock = std::lock_guard{service_lock};
-
     Service* svc = nullptr;
 
     switch (function.target) {
@@ -423,22 +428,59 @@
 
     if (svc == nullptr) {
         LOG(ERROR) << "Control message: Could not find '" << name << "' for ctl." << msg
-                   << " from pid: " << from_pid << " (" << process_cmdline << ")";
+                   << " from pid: " << pid << " (" << process_cmdline << ")";
         return false;
     }
 
     if (auto result = function.action(svc); !result.ok()) {
         LOG(ERROR) << "Control message: Could not ctl." << msg << " for '" << name
-                   << "' from pid: " << from_pid << " (" << process_cmdline
-                   << "): " << result.error();
+                   << "' from pid: " << pid << " (" << process_cmdline << "): " << result.error();
         return false;
     }
 
     LOG(INFO) << "Control message: Processed ctl." << msg << " for '" << name
-              << "' from pid: " << from_pid << " (" << process_cmdline << ")";
+              << "' from pid: " << pid << " (" << process_cmdline << ")";
     return true;
 }
 
+bool QueueControlMessage(const std::string& message, const std::string& name, pid_t pid, int fd) {
+    auto lock = std::lock_guard{pending_control_messages_lock};
+    if (pending_control_messages.size() > 100) {
+        LOG(ERROR) << "Too many pending control messages, dropped '" << message << "' for '" << name
+                   << "' from pid: " << pid;
+        return false;
+    }
+    pending_control_messages.push({message, name, pid, fd});
+    WakeEpoll();
+    return true;
+}
+
+static void HandleControlMessages() {
+    auto lock = std::unique_lock{pending_control_messages_lock};
+    // Init historically would only execute handle one property message, including control messages
+    // in each iteration of its main loop.  We retain this behavior here to prevent starvation of
+    // other actions in the main loop.
+    if (!pending_control_messages.empty()) {
+        auto control_message = pending_control_messages.front();
+        pending_control_messages.pop();
+        lock.unlock();
+
+        bool success = HandleControlMessage(control_message.message, control_message.name,
+                                            control_message.pid);
+
+        uint32_t response = success ? PROP_SUCCESS : PROP_ERROR_HANDLE_CONTROL_MESSAGE;
+        if (control_message.fd != -1) {
+            TEMP_FAILURE_RETRY(send(control_message.fd, &response, sizeof(response), 0));
+            close(control_message.fd);
+        }
+        lock.lock();
+    }
+    // If we still have items to process, make sure we wake back up to do so.
+    if (!pending_control_messages.empty()) {
+        WakeEpoll();
+    }
+}
+
 static Result<void> wait_for_coldboot_done_action(const BuiltinArguments& args) {
     if (!prop_waiter_state.StartWaiting(kColdBootDoneProp, "true")) {
         LOG(FATAL) << "Could not wait for '" << kColdBootDoneProp << "'";
@@ -588,7 +630,6 @@
     }
 
     auto found = false;
-    auto lock = std::lock_guard{service_lock};
     for (const auto& service : ServiceList::GetInstance()) {
         auto svc = service.get();
         if (svc->keycodes() == keycodes) {
@@ -659,22 +700,6 @@
     }
 }
 
-void SendStopSendingMessagesMessage() {
-    auto init_message = InitMessage{};
-    init_message.set_stop_sending_messages(true);
-    if (auto result = SendMessage(property_fd, init_message); !result.ok()) {
-        LOG(ERROR) << "Failed to send 'stop sending messages' message: " << result.error();
-    }
-}
-
-void SendStartSendingMessagesMessage() {
-    auto init_message = InitMessage{};
-    init_message.set_start_sending_messages(true);
-    if (auto result = SendMessage(property_fd, init_message); !result.ok()) {
-        LOG(ERROR) << "Failed to send 'start sending messages' message: " << result.error();
-    }
-}
-
 int SecondStageMain(int argc, char** argv) {
     if (REBOOT_BOOTLOADER_ON_PANIC) {
         InstallRebootSignalHandlers();
@@ -796,7 +821,6 @@
     Keychords keychords;
     am.QueueBuiltinAction(
             [&epoll, &keychords](const BuiltinArguments& args) -> Result<void> {
-                auto lock = std::lock_guard{service_lock};
                 for (const auto& svc : ServiceList::GetInstance()) {
                     keychords.Register(svc->keycodes());
                 }
@@ -863,6 +887,7 @@
                 (*function)();
             }
         }
+        HandleControlMessages();
     }
 
     return 0;
diff --git a/init/init.h b/init/init.h
index bcf24e7..27f64e2 100644
--- a/init/init.h
+++ b/init/init.h
@@ -38,11 +38,9 @@
 void ResetWaitForProp();
 
 void SendLoadPersistentPropertiesMessage();
-void SendStopSendingMessagesMessage();
-void SendStartSendingMessagesMessage();
 
 void PropertyChanged(const std::string& name, const std::string& value);
-bool HandleControlMessage(const std::string& msg, const std::string& name, pid_t from_pid);
+bool QueueControlMessage(const std::string& message, const std::string& name, pid_t pid, int fd);
 
 int SecondStageMain(int argc, char** argv);
 
diff --git a/init/init_test.cpp b/init/init_test.cpp
index 3053bd8..caf3e03 100644
--- a/init/init_test.cpp
+++ b/init/init_test.cpp
@@ -167,7 +167,6 @@
 
     ServiceList service_list;
     TestInitText(init_script, BuiltinFunctionMap(), {}, &service_list);
-    auto lock = std::lock_guard{service_lock};
     ASSERT_EQ(1, std::distance(service_list.begin(), service_list.end()));
 
     auto service = service_list.begin()->get();
diff --git a/init/lmkd_service.cpp b/init/lmkd_service.cpp
index a531d0a..dd1ab4d 100644
--- a/init/lmkd_service.cpp
+++ b/init/lmkd_service.cpp
@@ -79,8 +79,7 @@
 }
 
 static void RegisterServices(pid_t exclude_pid) {
-    auto lock = std::lock_guard{service_lock};
-    for (const auto& service : ServiceList::GetInstance()) {
+    for (const auto& service : ServiceList::GetInstance().services()) {
         auto svc = service.get();
         if (svc->oom_score_adjust() != DEFAULT_OOM_SCORE_ADJUST) {
             // skip if process is excluded or not yet forked (pid==0)
diff --git a/init/mount_namespace.cpp b/init/mount_namespace.cpp
index aa36849..0749fe3 100644
--- a/init/mount_namespace.cpp
+++ b/init/mount_namespace.cpp
@@ -29,7 +29,6 @@
 #include <android-base/unique_fd.h>
 #include <apex_manifest.pb.h>
 
-#include "property_service.h"
 #include "util.h"
 
 namespace android {
@@ -291,14 +290,6 @@
         return true;
     }
     if (default_ns_id != GetMountNamespaceId()) {
-        // The property service thread and its descendent threads must be in the correct mount
-        // namespace to call Service::Start(), however setns() only operates on a single thread and
-        // fails when secondary threads attempt to join the same mount namespace.  Therefore, we
-        // must join the property service thread and its descendents before the setns() call.  Those
-        // threads are then started again after the setns() call, and they'll be in the proper
-        // namespace.
-        PausePropertyService();
-
         if (setns(default_ns_fd.get(), CLONE_NEWNS) == -1) {
             PLOG(ERROR) << "Failed to switch back to the default mount namespace.";
             return false;
@@ -308,8 +299,6 @@
             LOG(ERROR) << result.error();
             return false;
         }
-
-        ResumePropertyService();
     }
 
     LOG(INFO) << "Switched to default mount namespace";
diff --git a/init/property_service.cpp b/init/property_service.cpp
index 319a241..8206522 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -95,6 +95,7 @@
 static int from_init_socket = -1;
 static int init_socket = -1;
 static bool accept_messages = false;
+static std::mutex accept_messages_lock;
 static std::thread property_service_thread;
 
 static PropertyInfoAreaFile property_info_area;
@@ -117,6 +118,16 @@
     return 0;
 }
 
+void StartSendingMessages() {
+    auto lock = std::lock_guard{accept_messages_lock};
+    accept_messages = true;
+}
+
+void StopSendingMessages() {
+    auto lock = std::lock_guard{accept_messages_lock};
+    accept_messages = true;
+}
+
 bool CanReadProperty(const std::string& source_context, const std::string& name) {
     const char* target_context = nullptr;
     property_info_area->GetPropertyInfo(name.c_str(), &target_context, nullptr);
@@ -186,138 +197,49 @@
     }
     // If init hasn't started its main loop, then it won't be handling property changed messages
     // anyway, so there's no need to try to send them.
+    auto lock = std::lock_guard{accept_messages_lock};
     if (accept_messages) {
         PropertyChanged(name, value);
     }
     return PROP_SUCCESS;
 }
 
-template <typename T>
-class SingleThreadExecutor {
+class AsyncRestorecon {
   public:
-    virtual ~SingleThreadExecutor() {}
-
-    template <typename F = T>
-    void Run(F&& item) {
+    void TriggerRestorecon(const std::string& path) {
         auto guard = std::lock_guard{mutex_};
-        items_.emplace(std::forward<F>(item));
+        paths_.emplace(path);
 
-        if (thread_state_ == ThreadState::kRunning || thread_state_ == ThreadState::kStopped) {
-            return;
-        }
-
-        if (thread_state_ == ThreadState::kPendingJoin) {
-            thread_.join();
-        }
-
-        StartThread();
-    }
-
-    void StopAndJoin() {
-        auto lock = std::unique_lock{mutex_};
-        if (thread_state_ == ThreadState::kPendingJoin) {
-            thread_.join();
-        } else if (thread_state_ == ThreadState::kRunning) {
-            thread_state_ = ThreadState::kStopped;
-            lock.unlock();
-            thread_.join();
-            lock.lock();
-        }
-
-        thread_state_ = ThreadState::kStopped;
-    }
-
-    void Restart() {
-        auto guard = std::lock_guard{mutex_};
-        if (items_.empty()) {
-            thread_state_ = ThreadState::kNotStarted;
-        } else {
-            StartThread();
-        }
-    }
-
-    void MaybeJoin() {
-        auto guard = std::lock_guard{mutex_};
-        if (thread_state_ == ThreadState::kPendingJoin) {
-            thread_.join();
-            thread_state_ = ThreadState::kNotStarted;
+        if (!thread_started_) {
+            thread_started_ = true;
+            std::thread{&AsyncRestorecon::ThreadFunction, this}.detach();
         }
     }
 
   private:
-    virtual void Execute(T&& item) = 0;
-
-    void StartThread() {
-        thread_state_ = ThreadState::kRunning;
-        auto thread = std::thread{&SingleThreadExecutor::ThreadFunction, this};
-        std::swap(thread_, thread);
-    }
-
     void ThreadFunction() {
         auto lock = std::unique_lock{mutex_};
 
-        while (!items_.empty()) {
-            auto item = items_.front();
-            items_.pop();
+        while (!paths_.empty()) {
+            auto path = paths_.front();
+            paths_.pop();
 
             lock.unlock();
-            Execute(std::move(item));
+            if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE) != 0) {
+                LOG(ERROR) << "Asynchronous restorecon of '" << path << "' failed'";
+            }
+            android::base::SetProperty(kRestoreconProperty, path);
             lock.lock();
         }
 
-        if (thread_state_ != ThreadState::kStopped) {
-            thread_state_ = ThreadState::kPendingJoin;
-        }
+        thread_started_ = false;
     }
 
     std::mutex mutex_;
-    std::queue<T> items_;
-    enum class ThreadState {
-        kNotStarted,  // Initial state when starting the program or when restarting with no items to
-                      // process.
-        kRunning,     // The thread is running and is in a state that it will process new items if
-                      // are run.
-        kPendingJoin,  // The thread has run to completion and is pending join().  A new thread must
-                       // be launched for new items to be processed.
-        kStopped,  // This executor has stopped and will not process more items until Restart() is
-                   // called.  Currently pending items will be processed and the thread will be
-                   // joined.
-    };
-    ThreadState thread_state_ = ThreadState::kNotStarted;
-    std::thread thread_;
+    std::queue<std::string> paths_;
+    bool thread_started_ = false;
 };
 
-class RestoreconThread : public SingleThreadExecutor<std::string> {
-    virtual void Execute(std::string&& path) override {
-        if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE) != 0) {
-            LOG(ERROR) << "Asynchronous restorecon of '" << path << "' failed'";
-        }
-        android::base::SetProperty(kRestoreconProperty, path);
-    }
-};
-
-struct ControlMessageInfo {
-    std::string message;
-    std::string name;
-    pid_t pid;
-    int fd;
-};
-
-class ControlMessageThread : public SingleThreadExecutor<ControlMessageInfo> {
-    virtual void Execute(ControlMessageInfo&& info) override {
-        bool success = HandleControlMessage(info.message, info.name, info.pid);
-
-        uint32_t response = success ? PROP_SUCCESS : PROP_ERROR_HANDLE_CONTROL_MESSAGE;
-        if (info.fd != -1) {
-            TEMP_FAILURE_RETRY(send(info.fd, &response, sizeof(response), 0));
-            close(info.fd);
-        }
-    }
-};
-
-static RestoreconThread restorecon_thread;
-static ControlMessageThread control_message_thread;
-
 class SocketConnection {
   public:
     SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}
@@ -454,22 +376,25 @@
 
 static uint32_t SendControlMessage(const std::string& msg, const std::string& name, pid_t pid,
                                    SocketConnection* socket, std::string* error) {
+    auto lock = std::lock_guard{accept_messages_lock};
     if (!accept_messages) {
         *error = "Received control message after shutdown, ignoring";
         return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
     }
 
-    // We must release the fd before spawning the thread, otherwise there will be a race with the
-    // thread. If the thread calls close() before this function calls Release(), then fdsan will see
-    // the wrong tag and abort().
+    // We must release the fd before sending it to init, otherwise there will be a race with init.
+    // If init calls close() before Release(), then fdsan will see the wrong tag and abort().
     int fd = -1;
     if (socket != nullptr && SelinuxGetVendorAndroidVersion() > __ANDROID_API_Q__) {
         fd = socket->Release();
     }
 
-    // Handling a control message likely calls SetProperty, which we must synchronously handle,
-    // therefore we must fork a thread to handle it.
-    control_message_thread.Run({msg, name, pid, fd});
+    bool queue_success = QueueControlMessage(msg, name, pid, fd);
+    if (!queue_success && fd != -1) {
+        uint32_t response = PROP_ERROR_HANDLE_CONTROL_MESSAGE;
+        TEMP_FAILURE_RETRY(send(fd, &response, sizeof(response), 0));
+        close(fd);
+    }
 
     return PROP_SUCCESS;
 }
@@ -571,7 +496,8 @@
     // We use a thread to do this restorecon operation to prevent holding up init, as it may take
     // a long time to complete.
     if (name == kRestoreconProperty && cr.pid != 1 && !value.empty()) {
-        restorecon_thread.Run(value);
+        static AsyncRestorecon async_restorecon;
+        async_restorecon.TriggerRestorecon(value);
         return PROP_SUCCESS;
     }
 
@@ -1152,8 +1078,6 @@
     PropertyLoadBootDefaults();
 }
 
-static bool pause_property_service = false;
-
 static void HandleInitSocket() {
     auto message = ReadMessage(init_socket);
     if (!message.ok()) {
@@ -1180,18 +1104,6 @@
             persistent_properties_loaded = true;
             break;
         }
-        case InitMessage::kStopSendingMessages: {
-            accept_messages = false;
-            break;
-        }
-        case InitMessage::kStartSendingMessages: {
-            accept_messages = true;
-            break;
-        }
-        case InitMessage::kPausePropertyService: {
-            pause_property_service = true;
-            break;
-        }
         default:
             LOG(ERROR) << "Unknown message type from init: " << init_message.msg_case();
     }
@@ -1212,7 +1124,7 @@
         LOG(FATAL) << result.error();
     }
 
-    while (!pause_property_service) {
+    while (true) {
         auto pending_functions = epoll.Wait(std::nullopt);
         if (!pending_functions.ok()) {
             LOG(ERROR) << pending_functions.error();
@@ -1221,34 +1133,9 @@
                 (*function)();
             }
         }
-        control_message_thread.MaybeJoin();
-        restorecon_thread.MaybeJoin();
     }
 }
 
-void SendStopPropertyServiceMessage() {
-    auto init_message = InitMessage{};
-    init_message.set_pause_property_service(true);
-    if (auto result = SendMessage(from_init_socket, init_message); !result.ok()) {
-        LOG(ERROR) << "Failed to send stop property service message: " << result.error();
-    }
-}
-
-void PausePropertyService() {
-    control_message_thread.StopAndJoin();
-    restorecon_thread.StopAndJoin();
-    SendStopPropertyServiceMessage();
-    property_service_thread.join();
-}
-
-void ResumePropertyService() {
-    pause_property_service = false;
-    auto new_thread = std::thread{PropertyServiceThread};
-    property_service_thread.swap(new_thread);
-    restorecon_thread.Restart();
-    control_message_thread.Restart();
-}
-
 void StartPropertyService(int* epoll_socket) {
     InitPropertySet("ro.property_service.version", "2");
 
@@ -1258,7 +1145,7 @@
     }
     *epoll_socket = from_init_socket = sockets[0];
     init_socket = sockets[1];
-    accept_messages = true;
+    StartSendingMessages();
 
     if (auto result = CreateSocket(PROP_SERVICE_NAME, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
                                    false, 0666, 0, 0, {});
diff --git a/init/property_service.h b/init/property_service.h
index e921326..2d49a36 100644
--- a/init/property_service.h
+++ b/init/property_service.h
@@ -31,8 +31,9 @@
 
 void PropertyInit();
 void StartPropertyService(int* epoll_socket);
-void ResumePropertyService();
-void PausePropertyService();
+
+void StartSendingMessages();
+void StopSendingMessages();
 
 }  // namespace init
 }  // namespace android
diff --git a/init/property_service.proto b/init/property_service.proto
index 36245b2..08268d9 100644
--- a/init/property_service.proto
+++ b/init/property_service.proto
@@ -41,6 +41,5 @@
         bool load_persistent_properties = 1;
         bool stop_sending_messages = 2;
         bool start_sending_messages = 3;
-        bool pause_property_service = 4;
     };
 }
diff --git a/init/reboot.cpp b/init/reboot.cpp
index cad192d..f006df3 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -59,6 +59,7 @@
 #include "builtin_arguments.h"
 #include "init.h"
 #include "mount_namespace.h"
+#include "property_service.h"
 #include "reboot_utils.h"
 #include "service.h"
 #include "service_list.h"
@@ -85,7 +86,7 @@
 
 static const std::set<std::string> kDebuggingServices{"tombstoned", "logd", "adbd", "console"};
 
-static std::vector<Service*> GetDebuggingServices(bool only_post_data) REQUIRES(service_lock) {
+static std::vector<Service*> GetDebuggingServices(bool only_post_data) {
     std::vector<Service*> ret;
     ret.reserve(kDebuggingServices.size());
     for (const auto& s : ServiceList::GetInstance()) {
@@ -181,7 +182,7 @@
 };
 
 // Turn off backlight while we are performing power down cleanup activities.
-static void TurnOffBacklight() REQUIRES(service_lock) {
+static void TurnOffBacklight() {
     Service* service = ServiceList::GetInstance().FindService("blank_screen");
     if (service == nullptr) {
         LOG(WARNING) << "cannot find blank_screen in TurnOffBacklight";
@@ -589,7 +590,6 @@
     // Start reboot monitor thread
     sem_post(&reboot_semaphore);
 
-    auto lock = std::lock_guard{service_lock};
     // watchdogd is a vendor specific component but should be alive to complete shutdown safely.
     const std::set<std::string> to_starts{"watchdogd"};
     std::vector<Service*> stop_first;
@@ -709,21 +709,15 @@
     // Skip wait for prop if it is in progress
     ResetWaitForProp();
     // Clear EXEC flag if there is one pending
-    auto lock = std::lock_guard{service_lock};
     for (const auto& s : ServiceList::GetInstance()) {
         s->UnSetExec();
     }
-    // We no longer process messages about properties changing coming from property service, so we
-    // need to tell property service to stop sending us these messages, otherwise it'll fill the
-    // buffers and block indefinitely, causing future property sets, including those that init makes
-    // during shutdown in Service::NotifyStateChange() to also block indefinitely.
-    SendStopSendingMessagesMessage();
 }
 
 static void LeaveShutdown() {
     LOG(INFO) << "Leaving shutdown mode";
     shutting_down = false;
-    SendStartSendingMessagesMessage();
+    StartSendingMessages();
 }
 
 static Result<void> UnmountAllApexes() {
@@ -753,7 +747,6 @@
         return Error() << "Failed to set sys.init.userspace_reboot.in_progress property";
     }
     EnterShutdown();
-    auto lock = std::lock_guard{service_lock};
     if (!SetProperty("sys.powerctl", "")) {
         return Error() << "Failed to reset sys.powerctl property";
     }
@@ -914,7 +907,6 @@
                 run_fsck = true;
             } else if (cmd_params[1] == "thermal") {
                 // Turn off sources of heat immediately.
-                auto lock = std::lock_guard{service_lock};
                 TurnOffBacklight();
                 // run_fsck is false to avoid delay
                 cmd = ANDROID_RB_THERMOFF;
@@ -985,6 +977,10 @@
         return;
     }
 
+    // We do not want to process any messages (queue'ing triggers, shutdown messages, control
+    // messages, etc) from properties during reboot.
+    StopSendingMessages();
+
     if (userspace_reboot) {
         HandleUserspaceReboot();
         return;
diff --git a/init/service.h b/init/service.h
index d2a4462..cf3f0c2 100644
--- a/init/service.h
+++ b/init/service.h
@@ -27,14 +27,12 @@
 #include <vector>
 
 #include <android-base/chrono_utils.h>
-#include <android-base/thread_annotations.h>
 #include <cutils/iosched_policy.h>
 
 #include "action.h"
 #include "capabilities.h"
 #include "keyword_map.h"
 #include "parser.h"
-#include "service_lock.h"
 #include "service_utils.h"
 #include "subcontext.h"
 
@@ -79,17 +77,17 @@
 
     bool IsRunning() { return (flags_ & SVC_RUNNING) != 0; }
     bool IsEnabled() { return (flags_ & SVC_DISABLED) == 0; }
-    Result<void> ExecStart() REQUIRES(service_lock);
-    Result<void> Start() REQUIRES(service_lock);
-    Result<void> StartIfNotDisabled() REQUIRES(service_lock);
-    Result<void> StartIfPostData() REQUIRES(service_lock);
-    Result<void> Enable() REQUIRES(service_lock);
+    Result<void> ExecStart();
+    Result<void> Start();
+    Result<void> StartIfNotDisabled();
+    Result<void> StartIfPostData();
+    Result<void> Enable();
     void Reset();
     void ResetIfPostData();
     void Stop();
     void Terminate();
     void Timeout();
-    void Restart() REQUIRES(service_lock);
+    void Restart();
     void Reap(const siginfo_t& siginfo);
     void DumpState() const;
     void SetShutdownCritical() { flags_ |= SVC_SHUTDOWN_CRITICAL; }
diff --git a/init/service_list.h b/init/service_list.h
index 280a228..3b9018b 100644
--- a/init/service_list.h
+++ b/init/service_list.h
@@ -17,13 +17,9 @@
 #pragma once
 
 #include <memory>
-#include <mutex>
 #include <vector>
 
-#include <android-base/thread_annotations.h>
-
 #include "service.h"
-#include "service_lock.h"
 
 namespace android {
 namespace init {
@@ -36,16 +32,16 @@
     ServiceList();
     size_t CheckAllCommands();
 
-    void AddService(std::unique_ptr<Service> service) REQUIRES(service_lock);
-    void RemoveService(const Service& svc) REQUIRES(service_lock);
+    void AddService(std::unique_ptr<Service> service);
+    void RemoveService(const Service& svc);
     template <class UnaryPredicate>
-    void RemoveServiceIf(UnaryPredicate predicate) REQUIRES(service_lock) {
+    void RemoveServiceIf(UnaryPredicate predicate) {
         services_.erase(std::remove_if(services_.begin(), services_.end(), predicate),
                         services_.end());
     }
 
     template <typename T, typename F = decltype(&Service::name)>
-    Service* FindService(T value, F function = &Service::name) const REQUIRES(service_lock) {
+    Service* FindService(T value, F function = &Service::name) const {
         auto svc = std::find_if(services_.begin(), services_.end(),
                                 [&function, &value](const std::unique_ptr<Service>& s) {
                                     return std::invoke(function, s) == value;
@@ -56,7 +52,7 @@
         return nullptr;
     }
 
-    Service* FindInterface(const std::string& interface_name) REQUIRES(service_lock) {
+    Service* FindInterface(const std::string& interface_name) {
         for (const auto& svc : services_) {
             if (svc->interfaces().count(interface_name) > 0) {
                 return svc.get();
@@ -66,20 +62,18 @@
         return nullptr;
     }
 
-    void DumpState() const REQUIRES(service_lock);
+    void DumpState() const;
 
-    auto begin() const REQUIRES(service_lock) { return services_.begin(); }
-    auto end() const REQUIRES(service_lock) { return services_.end(); }
-    const std::vector<std::unique_ptr<Service>>& services() const REQUIRES(service_lock) {
-        return services_;
-    }
-    const std::vector<Service*> services_in_shutdown_order() const REQUIRES(service_lock);
+    auto begin() const { return services_.begin(); }
+    auto end() const { return services_.end(); }
+    const std::vector<std::unique_ptr<Service>>& services() const { return services_; }
+    const std::vector<Service*> services_in_shutdown_order() const;
 
     void MarkPostData();
     bool IsPostData();
-    void MarkServicesUpdate() REQUIRES(service_lock);
+    void MarkServicesUpdate();
     bool IsServicesUpdated() const { return services_update_finished_; }
-    void DelayService(const Service& service) REQUIRES(service_lock);
+    void DelayService(const Service& service);
 
     void ResetState() {
         post_data_ = false;
diff --git a/init/service_lock.cpp b/init/service_lock.cpp
deleted file mode 100644
index 404d439..0000000
--- a/init/service_lock.cpp
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "service_lock.h"
-
-namespace android {
-namespace init {
-
-RecursiveMutex service_lock;
-
-}  // namespace init
-}  // namespace android
diff --git a/init/service_lock.h b/init/service_lock.h
deleted file mode 100644
index 6b94271..0000000
--- a/init/service_lock.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-
-#include <mutex>
-
-#include <android-base/thread_annotations.h>
-
-namespace android {
-namespace init {
-
-// This class exists to add thread annotations, since they're absent from std::recursive_mutex.
-
-class CAPABILITY("mutex") RecursiveMutex {
-  public:
-    void lock() ACQUIRE() { mutex_.lock(); }
-    void unlock() RELEASE() { mutex_.unlock(); }
-
-  private:
-    std::recursive_mutex mutex_;
-};
-
-extern RecursiveMutex service_lock;
-
-}  // namespace init
-}  // namespace android
diff --git a/init/service_parser.cpp b/init/service_parser.cpp
index 51f4c97..560f693 100644
--- a/init/service_parser.cpp
+++ b/init/service_parser.cpp
@@ -168,7 +168,6 @@
 
     const std::string fullname = interface_name + "/" + instance_name;
 
-    auto lock = std::lock_guard{service_lock};
     for (const auto& svc : *service_list_) {
         if (svc->interfaces().count(fullname) > 0) {
             return Error() << "Interface '" << fullname << "' redefined in " << service_->name()
@@ -599,7 +598,6 @@
         }
     }
 
-    auto lock = std::lock_guard{service_lock};
     Service* old_service = service_list_->FindService(service_->name());
     if (old_service) {
         if (!service_->is_override()) {
diff --git a/init/sigchld_handler.cpp b/init/sigchld_handler.cpp
index 064d64d..9b2c7d9 100644
--- a/init/sigchld_handler.cpp
+++ b/init/sigchld_handler.cpp
@@ -64,8 +64,6 @@
     std::string wait_string;
     Service* service = nullptr;
 
-    auto lock = std::lock_guard{service_lock};
-
     if (SubcontextChildReap(pid)) {
         name = "Subcontext";
     } else {