Files
hardware_interfaces/gnss/aidl/default/GnssNavigationMessageInterface.h
Yu-Han Yang e28dd7900d Fix a deadlock in emulator HAL implementation
Before this change, a start() call will wait for previous threads to
finish. However, in ListenerMultiplexer.java in the framework, start(),
stop(), and deliverListener() calls are contending for the same lock.
Therefore, if a waiting start() is holding the lock, while the
almost-finishing thread is also going to hold that lock for calling
deliverListener(), a deadlock will happen.

This CL moves the waiting logic into the new thread of the start() call,
so that start() will return immediately. The new thread will wait for
the old thread to finish, and then start the actual work.

Bug: 299563185
Test: atest CtsLocationGnssTestCases
Change-Id: Ic2993a6d82c24688fa98d26d336c85518c683cf6
2023-10-20 21:53:38 +00:00

54 lines
1.7 KiB
C++

/*
* Copyright (C) 2021 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 <aidl/android/hardware/gnss/BnGnssNavigationMessageInterface.h>
#include <atomic>
#include <future>
#include <thread>
#include "Utils.h"
namespace aidl::android::hardware::gnss {
struct GnssNavigationMessageInterface : public BnGnssNavigationMessageInterface {
public:
GnssNavigationMessageInterface();
~GnssNavigationMessageInterface();
ndk::ScopedAStatus setCallback(
const std::shared_ptr<IGnssNavigationMessageCallback>& callback) override;
ndk::ScopedAStatus close() override;
private:
void start();
void stop();
void reportMessage(const IGnssNavigationMessageCallback::GnssNavigationMessage& message);
void waitForStoppingThreads();
std::atomic<long> mMinIntervalMillis;
std::atomic<bool> mIsActive;
std::vector<std::thread> mThreads;
std::vector<std::future<void>> mFutures;
::android::hardware::gnss::common::ThreadBlocker mThreadBlocker;
// Guarded by mMutex
static std::shared_ptr<IGnssNavigationMessageCallback> sCallback;
// Synchronization lock for sCallback
mutable std::mutex mMutex;
};
} // namespace aidl::android::hardware::gnss