通过ANR来查看死锁

最新推荐文章于 2023-04-21 16:05:06 发布

转载最新推荐文章于 2023-04-21 16:05:06 发布 · 1k 阅读

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本文介绍如何在Android应用中使用ANR机制检测并分析死锁情况，通过生成traces.txt文件，开发者可以轻松定位到导致死锁的线程和代码片段。实例展示了DeadLockTraceActivity和ThreadDeadLockExample类的实现，以及如何手动触发死锁并生成对应traces.txt文件的过程。

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死锁通常很难查找。但是在Android我们可以ANR来得到traces.txt。在traces.txt中可以查看那些线程在wait，当然死锁的线程也在其中。这样对查找死锁大大提供了方便。

注意：方式ANR后，在手机中就会生成如下文件data\anr\traces.txt

下面直接给出实例。

文件1

DeadLockTraceActivity.java文件

package com.gameloft.robin;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

public class DeadLockTraceActivity extends Activity {

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.deadlock_trace);

}

String tag="robin";

public void onResume()

{

super.onResume();

new ThreadDeadLockExample().start();

Handler handler=new Handler();

Runnable run=new Runnable(){public void run(){forceWait();}};

handler.post(run);

}

synchronized void forceWait()

{

try {

wait(60000);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

文件2

ThreadDeadLockExample.java文件

package com.gameloft.robin;

import java.util.concurrent.locks.ReentrantLock;

import android.util.Log;

public class ThreadDeadLockExample{

private final ReentrantLock lockA = new ReentrantLock(true);

private final ReentrantLock lockB = new ReentrantLock(true);

String tag="robin";

void start()

{

Log.i(tag, "ThreadDeadLockExample start");

new ThreadA("ThreadA").start();

new ThreadB("ThreadB").start();

}

class ThreadA extends Thread

{

ThreadA(String name)

{

super(name);

}

public void run()

{

Log.i(tag, "try to lock A"+" in ThreadA");

lockA.lock();

try {

Thread.sleep(1000);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

Log.i(tag, "lock A successful"+" in ThreadA");

Log.i(tag, "try to lock B"+" in ThreadA");

lockB.lock();

Log.i(tag, "lock B successful"+" in ThreadA");

lockB.unlock();

Log.i(tag, "unlock B"+" in ThreadA");

lockA.unlock();

Log.i(tag, "unlock A"+" in ThreadA");

}

class ThreadB extends Thread

{

ThreadB(String name)

{

super(name);

}

public void run()

{

Log.i(tag, "try to lock B "+" in ThreadB");

lockB.lock();

try {

Thread.sleep(1000);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

Log.i(tag, "lock B successful"+" in ThreadB");

Log.i(tag, "try to lock A"+" in ThreadB");

lockA.lock();

Log.i(tag, "lock A successful"+" in ThreadB");

lockA.unlock();

Log.i(tag, "unlock A"+" in ThreadB");

lockB.unlock();

Log.i(tag, "unlock B"+" in ThreadB");

}

traces.txt 文件摘要

DALVIK THREADS:

"main" prio=5 tid=1 TIMED_WAIT

| group="main" sCount=1 dsCount=0 s=N obj=0x400208b8 self=0xcdf0

| sysTid=1732 nice=0 sched=0/0 cgrp=unknown handle=-1345026000

at java.lang.Object.wait(Native Method)

- waiting on <0x4a5ba4b0> (a com.gameloft.robin.DeadLockTraceActivity)

at java.lang.Object.wait(Object.java:326)

at com.gameloft.robin.DeadLockTraceActivity.forceWait(DeadLockTraceActivity.java:24)

at com.gameloft.robin.DeadLockTraceActivity$1.run(DeadLockTraceActivity.java:18)

at android.os.Handler.handleCallback(Handler.java:587)

at android.os.Handler.dispatchMessage(Handler.java:92)

at android.os.Looper.loop(Looper.java:123)

at android.app.ActivityThread.main(ActivityThread.java:4633)

at java.lang.reflect.Method.invokeNative(Native Method)

at java.lang.reflect.Method.invoke(Method.java:521)

at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

at dalvik.system.NativeStart.main(Native Method)

"ThreadB" prio=5 tid=10 WAIT

| group="main" sCount=1 dsCount=0 s=N obj=0x4a5bf868 self=0x2174f8

| sysTid=1741 nice=0 sched=0/0 cgrp=unknown handle=2192952

at java.lang.Object.wait(Native Method)

- waiting on <0x4a5bf980> (a java.lang.VMThread)

at java.lang.Thread.parkFor(Thread.java:1535)

at java.lang.LangAccessImpl.parkFor(LangAccessImpl.java:48)

at sun.misc.Unsafe.park(Unsafe.java:317)

at java.util.concurrent.locks.LockSupport.park(LockSupport.java:131)

at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:790)

at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:823)

at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1153)

at java.util.concurrent.locks.ReentrantLock$FairSync.lock(ReentrantLock.java:200)

at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:261)

at com.gameloft.robin.ThreadDeadLockExample$ThreadB.run(ThreadDeadLockExample.java:61)

"ThreadA" prio=5 tid=9 WAIT

| group="main" sCount=1 dsCount=0 s=N obj=0x4a5bf438 self=0x216858

| sysTid=1740 nice=0 sched=0/0 cgrp=unknown handle=2189720

at java.lang.Object.wait(Native Method)

- waiting on <0x4a5bf590> (a java.lang.VMThread)

at java.lang.Thread.parkFor(Thread.java:1535)

at java.lang.LangAccessImpl.parkFor(LangAccessImpl.java:48)

at sun.misc.Unsafe.park(Unsafe.java:317)

at java.util.concurrent.locks.LockSupport.park(LockSupport.java:131)

at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:790)

at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:823)

at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1153)

at java.util.concurrent.locks.ReentrantLock$FairSync.lock(ReentrantLock.java:200)

at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:261)

at com.gameloft.robin.ThreadDeadLockExample$ThreadA.run(ThreadDeadLockExample.java:35)

手动生成traces.txt文件

进入Android的shell命令行：

adb shell

得到app pid

$ps

发送信号

$kill -3 target_app_pid

检查 traces.txt 文件

$cd /data/anr

$ls -l