「Android」ANR入门学习笔记

ANR 全称是 Applicatipon Not Response ,Android 设计 ANR 的用意,是零碎通过与之交互的组件以及用户交互进行超时监控,用来判断利用过程是否存在卡死或响应过慢的问题

ANR 的触发起因

应用层导致 ANR 的起因:

  • 函数阻塞:如死循环、主线程 IO、解决大数据
  • 锁出错:主线程期待子线程的锁
  • 内存缓和:零碎调配给一个利用的内存是有下限的,长期处于内存缓和,会导致频繁内存替换,进而导致利用的一些操作超时

零碎导致ANR 的起因:

  • CPU 被抢占:一般来说,前台在玩游戏,可能会导致你的后盾播送被抢占
  • 零碎服务无奈及时响应:比方获取零碎联系人等,零碎的服务都是 Binder 机制,服务能力也是无限的,有可能零碎服务长时间不响应导致 ANR
  • 其余利用占用大量内存

ANR 的触发规范

简略来说,ANR 就是零碎响应超时,Android对于零碎是否响应超时有如下规范:

  • Service 触发ANR Service Timeout:比方前台服务在20s内未执行实现,后盾服务 Timeout 工夫是前台服务的10倍,200s;
  • Broadcast 触发ANR BroadcastQueue Timeout:比方前台播送在10s内未执行实现,后盾60s;
  • Provider 触发ANR ContentProvider Timeout:内容提供者,在 publish 过超时10s;
  • Input 触发ANR InputDispatching Timeout:输出事件散发超时5s,包含按键和触摸事件。
//ActiveServices.java// How long we wait for a service to finish executing.static final int SERVICE_BACKGROUND_TIMEOUT = SERVICE_TIMEOUT * 10;// How long the startForegroundService() grace period is to get around to// calling startForeground() before we ANR + stop it.static final int SERVICE_START_FOREGROUND_TIMEOUT = 10*1000;//ActivityManagerService.java// How long we allow a receiver to run before giving up on it.static final int BROADCAST_FG_TIMEOUT = 10*1000;static final int BROADCAST_BG_TIMEOUT = 60*1000;// How long we wait until we timeout on key dispatching.static final int KEY_DISPATCHING_TIMEOUT = 5*1000;

ANR 的触发流程

对于Service、Broadcast、Provider触发的ANR来说,相似于是一个埋炸弹、拆炸弹、引爆炸弹的过程,例如startService的时候:

惯例场景:埋炸弹 -- 拆炸弹

App->AMS: 启动ServiceApp->Handler: 启动规范工夫20s倒计时(埋炸弹)AMS-->App: 启动实现App->Handler: 勾销倒计时(拆炸弹)

ANR场景:埋炸弹 -- 引爆炸弹

App->AMS: 启动ServiceApp->Handler: 启动规范工夫20s倒计时(埋炸弹)Note right of AMS: 20s内未实现Service启动Note right of Handler: 20s内未勾销Handler->AMS: 触发ANR(引爆炸弹)

对于Input触发的ANR来说,与Service、Broadcast、Provider触发的ANR有所不同,其并非工夫到了就肯定会引爆炸弹(触发ANR),而是在后续的Input事件上报的过程中,才会去被动检测前一个正在解决的事件是否超时。若超时则触发ANR,反之则重置计时器。

ANR 的dump流程

不论 ANR 是怎么产生的,最终逻辑都会调用appNotResponding函数:

graph TDActivityManagerService#inputDispatchingTimedOut--> AnrHelper#appNotResponding--> AnrConsumerThread#run--> AnrRecord#appNotResponding--> ProcessRecord#appNotResponding
//com.android.server.am.ProcessRecord.javavoid appNotResponding(String activityShortComponentName, ApplicationInfo aInfo,        String parentShortComponentName, WindowProcessController parentProcess,        boolean aboveSystem, String annotation, boolean onlyDumpSelf) {    ArrayList<Integer> firstPids = new ArrayList<>(5);    SparseArray<Boolean> lastPids = new SparseArray<>(20);    mWindowProcessController.appEarlyNotResponding(annotation, () -> kill("anr",                ApplicationExitInfo.REASON_ANR, true));    long anrTime = SystemClock.uptimeMillis();    if (isMonitorCpuUsage()) {        mService.updateCpuStatsNow();    }    final boolean isSilentAnr;    synchronized (mService) {        //正文1        // PowerManager.reboot() can block for a long time, so ignore ANRs while shutting down.        //正在重启        if (mService.mAtmInternal.isShuttingDown()) {            Slog.i(TAG, "During shutdown skipping ANR: " + this + " " + annotation);            return;        } else if (isNotResponding()) {            //曾经处于ANR流程中            Slog.i(TAG, "Skipping duplicate ANR: " + this + " " + annotation);            return;        } else if (isCrashing()) {            //正在crash的状态            Slog.i(TAG, "Crashing app skipping ANR: " + this + " " + annotation);            return;        } else if (killedByAm) {            //app曾经被killed            Slog.i(TAG, "App already killed by AM skipping ANR: " + this + " " + annotation);            return;        } else if (killed) {            //app曾经死亡了            Slog.i(TAG, "Skipping died app ANR: " + this + " " + annotation);            return;        }        // In case we come through here for the same app before completing        // this one, mark as anring now so we will bail out.        //做个标记        setNotResponding(true);        // Log the ANR to the event log.        EventLog.writeEvent(EventLogTags.AM_ANR, userId, pid, processName, info.flags,                annotation);        // Dump thread traces as quickly as we can, starting with "interesting" processes.        firstPids.add(pid);        // Don't dump other PIDs if it's a background ANR or is requested to only dump self.        //正文2        //缄默的anr : 这里示意后盾anr        isSilentAnr = isSilentAnr();        if (!isSilentAnr && !onlyDumpSelf) {            int parentPid = pid;            if (parentProcess != null && parentProcess.getPid() > 0) {                parentPid = parentProcess.getPid();            }            if (parentPid != pid) firstPids.add(parentPid);            if (MY_PID != pid && MY_PID != parentPid) firstPids.add(MY_PID);            //抉择须要dump的过程            for (int i = getLruProcessList().size() - 1; i >= 0; i--) {                ProcessRecord r = getLruProcessList().get(i);                if (r != null && r.thread != null) {                    int myPid = r.pid;                    if (myPid > 0 && myPid != pid && myPid != parentPid && myPid != MY_PID) {                        if (r.isPersistent()) {                            firstPids.add(myPid);                            if (DEBUG_ANR) Slog.i(TAG, "Adding persistent proc: " + r);                        } else if (r.treatLikeActivity) {                            firstPids.add(myPid);                            if (DEBUG_ANR) Slog.i(TAG, "Adding likely IME: " + r);                        } else {                            lastPids.put(myPid, Boolean.TRUE);                            if (DEBUG_ANR) Slog.i(TAG, "Adding ANR proc: " + r);                        }                    }                }            }        }    }    ......    int[] pids = nativeProcs == null ? null : Process.getPidsForCommands(nativeProcs);    ArrayList<Integer> nativePids = null;    if (pids != null) {        nativePids = new ArrayList<>(pids.length);        for (int i : pids) {            nativePids.add(i);        }    }    // For background ANRs, don't pass the ProcessCpuTracker to    // avoid spending 1/2 second collecting stats to rank lastPids.    StringWriter tracesFileException = new StringWriter();    // To hold the start and end offset to the ANR trace file respectively.    final long[] offsets = new long[2];    //正文4    File tracesFile = ActivityManagerService.dumpStackTraces(firstPids,            isSilentAnr ? null : processCpuTracker, isSilentAnr ? null : lastPids,            nativePids, tracesFileException, offsets);        ......}

正文1处针对几种非凡状况进行解决:正在重启、曾经处于 ANR 流程中、正在crash、app 曾经被 killed 和 app 曾经死亡了,不必解决 ANR,间接 return。

正文2处 isSilentAnr 是示意以后是否为一个后盾 ANR,前台 ANR 会弹出无响应的 Dialog,后盾 ANR 会间接杀死过程。什么是前台 ANR:产生ANR的过程对用户来说有感知,就是前台 ANR,否则就是后盾 ANR。

正文3处,抉择须要 dump 的过程。产生 ANR 时,为了不便定位问题,会 dump 很多信息到 Trace 文件中。而 Trace 文件里蕴含着与 ANR 相关联的过程的 Trace 信息,因为产生 ANR 的起因有可能是其余的过程抢占了太多资源,或者 IPC 到其余过程的时候卡住导致的。须要被 dump 的过程分为3类:

  • firstPids:firstPids 是须要首先 dump 的重要过程,产生 ANR 的过程无论如何是肯定要被 dump 的,也是首先被 dump 的,所以第一个被加到 firstPids 中。如果是 SilentAnr(即后盾 ANR),不必再退出任何其余的过程。如果不是,须要进一步增加其余的过程:如果产生 ANR 的过程不是 system_server 过程的话,须要增加 system_server 过程;接下来轮询 AMS 保护的一个 LRU 的过程 List,如果最近拜访的过程蕴含了 persistent 的过程,或者带有 BIND_TREAT_LIKE_ACTVITY 标签的过程,都增加到 firstPids 中。
  • extraPids:LRU 过程 List 中的其余过程,都会首先增加到lastPids中,而后lastPids会进一步被选出最近CPU使用率高的过程,进一步组成 extraPids;
  • nativePids:nativePids 最为简略,是一些固定的 native 的零碎过程,定义在 WatchDog.java 中

正文4处,拿到须要 dump 的所有过程的 pid 后,AMS 开始依照 firstPids、 nativePids、extraPids 的程序 dump 这些过程的堆栈:

public static Pair<Long, Long> dumpStackTraces(String tracesFile, ArrayList<Integer> firstPids,        ArrayList<Integer> nativePids, ArrayList<Integer> extraPids) {    // 最多dump 20秒    long remainingTime = 20 * 1000;    // First collect all of the stacks of the most important pids.    if (firstPids != null) {        int num = firstPids.size();        for (int i = 0; i < num; i++) {            final int pid = firstPids.get(i);            final long timeTaken = dumpJavaTracesTombstoned(pid, tracesFile, remainingTime);            remainingTime -= timeTaken;            if (remainingTime <= 0) {                Slog.e(TAG, "Aborting stack trace dump (current firstPid=" + pid                        + "); deadline exceeded.");                return firstPidStart >= 0 ? new Pair<>(firstPidStart, firstPidEnd) : null;            }        }    }    ......}

依据程序取出后面传入的 firstPids、nativePids 、extraPids 的 pid,而后逐个去 dump 这些过程中所有的线程。因为此处有多个过程且每个过程通常有多个线程,所以这里规定了个最长 dump 工夫为20秒,超过则及时返回,这样能够确保ANR弹窗能够及时弹出(或者被 kill 掉)。

接下来的调用链为:

graph TDActivityManagerService#dumpJavaTracesTombstoned--> Debug#dumpJavaBacktraceToFileTimeout--> android_os_Debug#android_os_Debug_dumpJavaBacktraceToFileTimeout--> android_os_Debug#dumpTraces--> debuggerd_client#dump_backtrace_to_file_timeout--> debuggerd_client#debuggerd_trigger_dump
bool debuggerd_trigger_dump(pid_t tid, DebuggerdDumpType dump_type, unsigned int timeout_ms, unique_fd output_fd) {    //pid是从AMS那边传过来的,即须要dump堆栈的过程        pid_t pid = tid;    //......    // Send the signal.        //从android_os_Debug_dumpJavaBacktraceToFileTimeout过去的,dump_type为kDebuggerdJavaBacktrace    const int signal = (dump_type == kDebuggerdJavaBacktrace) ? SIGQUIT : BIONIC_SIGNAL_DEBUGGER;    sigval val = {.sival_int = (dump_type == kDebuggerdNativeBacktrace) ? 1 : 0};        //sigqueue:在队列中向指定过程发送一个信号和数据,胜利返回0    if (sigqueue(pid, signal, val) != 0) {      log_error(output_fd, errno, "failed to send signal to pid %d", pid);      return false;    }    //......    LOG(INFO) << TAG "done dumping process " << pid;    return true;}

除 Zygote 过程外,每个过程都会创立一个 SignalCatcher 守护线程,用于捕捉 SIGQUIT、SIGUSR1 信号,并采取相应的行为。
AMS 过程间接给须要 dump 堆栈那个过程发送了一个 SIGQUIT 信号,过程收到 SIGQUIT 信号之后便开始 dump。也就是说,每当一个过程产生 ANR 时,则会收到 SIGQUIT 信号。换言之,如果能监控到零碎发送的 SIGQUIT 信号,就能监控到产生了 ANR。

总结 ANR 的dump流程:
系统监控到 app 产生 ANR 后,收集了一些相干过程 pid(包含产生 ANR 的过程),筹备让这些过程 dump 堆栈,从而生成 ANR Trace 文件,接着零碎开始向这些过程发送 SIGQUIT 信号,过程收到 SIGQUIT 信号之后开始 dump 堆栈。

ANR 的剖析

获取 ANR 日志的形式:

  • adb pull /data/anr/
  • adb bugreport

trace文件剖析

----- pid 7761 at 2022-11-02 07:02:26 -----Cmd line: com.xfhy.watchsignaldemoBuild fingerprint: 'HUAWEI/LYA-AL00/HWLYA:10/HUAWEILYA-AL00/10.1.0.163C00:user/release-keys'ABI: 'arm64'Build type: optimizedZygote loaded classes=11918 post zygote classes=729Dumping registered class loaders#0 dalvik.system.PathClassLoader: [], parent #1#1 java.lang.BootClassLoader: [], no parent#2 dalvik.system.PathClassLoader: [/system/app/FeatureFramework/FeatureFramework.apk], no parent#3 dalvik.system.PathClassLoader: [/data/app/com.xfhy.watchsignaldemo-4tkKMWojrpHAf-Q3iecaHQ==/base.apk:/data/app/com.xfhy.watchsignaldemo-4tkKMWojrpHAf-Q3iecaHQ==/base.apk!classes2.dex:/data/app/com.xfhy.watchsignaldemo-4tkKMWojrpHAf-Q3iecaHQ==/base.apk!classes4.dex:/data/app/com.xfhy.watchsignaldemo-4tkKMWojrpHAf-Q3iecaHQ==/base.apk!classes3.dex], parent #1Done dumping class loadersIntern table: 44132 strong; 436 weakJNI: CheckJNI is off; globals=681 (plus 67 weak)Libraries: /data/app/com.xfhy.watchsignaldemo-4tkKMWojrpHAf-Q3iecaHQ==/lib/arm64/libwatchsignaldemo.so libandroid.so libcompiler_rt.so libhitrace_jni.so libhiview_jni.so libhwapsimpl_jni.so libiAwareSdk_jni.so libimonitor_jni.so libjavacore.so libjavacrypto.so libjnigraphics.so libmedia_jni.so libopenjdk.so libsoundpool.so libwebviewchromium_loader.so (15)//已调配堆内存大小26M,其中2442kb医用,总调配74512个对象Heap: 90% free, 2442KB/26MB; 74512 objectsTotal number of allocations 120222 //过程创立到当初一共创立了多少对象Total bytes allocated 10MB         //过程创立到当初一共申请了多少内存Total bytes freed 8173KB           //过程创立到当初一共开释了多少内存Free memory 23MB                   //不扩大堆的状况下可用的内存Free memory until GC 23MB          //GC前的可用内存Free memory until OOME 381MB       //OOM之前的可用内存,这个值很小的话,阐明曾经处于内存紧张状态,app可能是占用了过多的内存Total memory 26MB                  //以后总内存(已用+可用)Max memory 384MB                   //过程最多能申请的内存.....//省略GC相干信息//以后过程共17个线程DALVIK THREADS (17)://Signal Catcher线程调用栈"Signal Catcher" daemon prio=5 tid=4 Runnable  | group="system" sCount=0 dsCount=0 flags=0 obj=0x18c84570 self=0x7252417800  | sysTid=7772 nice=0 cgrp=default sched=0/0 handle=0x725354ad50  | state=R schedstat=( 16273959 1085938 5 ) utm=0 stm=1 core=4 HZ=100  | stack=0x7253454000-0x7253456000 stackSize=991KB  | held mutexes= "mutator lock"(shared held)  native: #00 pc 000000000042f8e8  /apex/com.android.runtime/lib64/libart.so (art::DumpNativeStack(std::__1::basic_ostream<char, std::__1::char_traits<char>>&, int, BacktraceMap*, char const*, art::ArtMethod*, void*, bool)+140)  native: #01 pc 0000000000523590  /apex/com.android.runtime/lib64/libart.so (art::Thread::DumpStack(std::__1::basic_ostream<char, std::__1::char_traits<char>>&, bool, BacktraceMap*, bool) const+508)  native: #02 pc 000000000053e75c  /apex/com.android.runtime/lib64/libart.so (art::DumpCheckpoint::Run(art::Thread*)+844)  native: #03 pc 000000000053735c  /apex/com.android.runtime/lib64/libart.so (art::ThreadList::RunCheckpoint(art::Closure*, art::Closure*)+504)  native: #04 pc 0000000000536744  /apex/com.android.runtime/lib64/libart.so (art::ThreadList::Dump(std::__1::basic_ostream<char, std::__1::char_traits<char>>&, bool)+1048)  native: #05 pc 0000000000536228  /apex/com.android.runtime/lib64/libart.so (art::ThreadList::DumpForSigQuit(std::__1::basic_ostream<char, std::__1::char_traits<char>>&)+884)  native: #06 pc 00000000004ee4d8  /apex/com.android.runtime/lib64/libart.so (art::Runtime::DumpForSigQuit(std::__1::basic_ostream<char, std::__1::char_traits<char>>&)+196)  native: #07 pc 000000000050250c  /apex/com.android.runtime/lib64/libart.so (art::SignalCatcher::HandleSigQuit()+1356)  native: #08 pc 0000000000501558  /apex/com.android.runtime/lib64/libart.so (art::SignalCatcher::Run(void*)+268)  native: #09 pc 00000000000cf7c0  /apex/com.android.runtime/lib64/bionic/libc.so (__pthread_start(void*)+36)  native: #10 pc 00000000000721a8  /apex/com.android.runtime/lib64/bionic/libc.so (__start_thread+64)  (no managed stack frames)"main" prio=5 tid=1 Sleeping  | group="main" sCount=1 dsCount=0 flags=1 obj=0x73907540 self=0x725f010800  | sysTid=7761 nice=-10 cgrp=default sched=1073741825/2 handle=0x72e60080d0  | state=S schedstat=( 281909898 5919799 311 ) utm=20 stm=7 core=4 HZ=100  | stack=0x7fca180000-0x7fca182000 stackSize=8192KB  | held mutexes=  at java.lang.Thread.sleep(Native method)  - sleeping on <0x00f895d9> (a java.lang.Object)  at java.lang.Thread.sleep(Thread.java:443)  - locked <0x00f895d9> (a java.lang.Object)  at java.lang.Thread.sleep(Thread.java:359)  at android.os.SystemClock.sleep(SystemClock.java:131)  at com.xfhy.watchsignaldemo.MainActivity.makeAnr(MainActivity.kt:35)  at java.lang.reflect.Method.invoke(Native method)  at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:441)  at android.view.View.performClick(View.java:7317)  at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1219)  at android.view.View.performClickInternal(View.java:7291)  at android.view.View.access$3600(View.java:838)  at android.view.View$PerformClick.run(View.java:28247)  at android.os.Handler.handleCallback(Handler.java:900)  at android.os.Handler.dispatchMessage(Handler.java:103)  at android.os.Looper.loop(Looper.java:219)  at android.app.ActivityThread.main(ActivityThread.java:8668)  at java.lang.reflect.Method.invoke(Native method)  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1109)  ... //此处省略残余的N个线程

trace 参数具体解读:

"Signal Catcher" daemon prio=5 tid=4 Runnable  | group="system" sCount=0 dsCount=0 flags=0 obj=0x18c84570 self=0x7252417800  | sysTid=7772 nice=0 cgrp=default sched=0/0 handle=0x725354ad50  | state=R schedstat=( 16273959 1085938 5 ) utm=0 stm=1 core=4 HZ=100  | stack=0x7253454000-0x7253456000 stackSize=991KB  | held mutexes= "mutator lock"(shared held)

第1行:"Signal Catcher" daemon prio=5 tid=4 Runnable

  • “Signal Catcher” daemon:线程名,有 daemon 示意守护线程
  • prio:线程优先级
  • tid:线程外部 id
  • 线程状态:Runnable

    一般来说,main线程处于 BLOCK、WAITING、TIMEWAITING 状态,基本上是函数阻塞导致的 ANR,如果 main 线程无异样,则应该排查 CPU 负载和内存环境。

第2行:| group="system" sCount=0 dsCount=0 flags=0 obj=0x18c84570 self=0x7252417800

  • group:线程所属的线程组
  • sCount:线程挂起次数
  • dsCount:用于调试的线程挂起次数
  • obj:以后线程关联的 Java 线程对象
  • self:以后线程地址

第3行:| sysTid=7772 nice=0 cgrp=default sched=0/0 handle=0x725354ad50

  • sysTid:线程真正意义上的 tid
  • nice:调度优先级,值越小则优先级越高
  • cgrp:过程所属的过程调度组
  • sched:调度策略
  • handle:函数解决地址

第4行:| state=R schedstat=( 16273959 1085938 5 ) utm=0 stm=1 core=4 HZ=100

  • state:线程状态
  • schedstat:CPU调度工夫统计(schedstat 括号中的3个数字顺次是Running、Runable、Switch,Running 工夫:CPU 运行的工夫,单位 ns,Runable 工夫:RQ 队列的等待时间,单位 ns,Switch 次数:CPU 调度切换次数)
  • utm/stm:用户态/内核态的 CPU 工夫
  • core:该线程的最初运行所在核
  • HZ:时钟频率

第5行:| stack=0x7253454000-0x7253456000 stackSize=991KB

  • stack:线程栈的地址区间
  • stackSize:栈的大小

第6行:| held mutexes= "mutator lock"(shared held)

  • mutex:所持有 mutex 类型,有独占锁 exclusive 和共享锁 shared 两类

案例剖析

主线程无卡顿,处于失常状态堆栈
"main" prio=5 tid=1 Native  | group="main" sCount=1 dsCount=0 flags=1 obj=0x74b38080 self=0x7ad9014c00  | sysTid=23081 nice=0 cgrp=default sched=0/0 handle=0x7b5fdc5548  | state=S schedstat=( 284838633 166738594 505 ) utm=21 stm=7 core=1 HZ=100  | stack=0x7fc95da000-0x7fc95dc000 stackSize=8MB  | held mutexes=  kernel: __switch_to+0xb0/0xbc  kernel: SyS_epoll_wait+0x288/0x364  kernel: SyS_epoll_pwait+0xb0/0x124  kernel: cpu_switch_to+0x38c/0x2258  native: #00 pc 000000000007cd8c  /system/lib64/libc.so (__epoll_pwait+8)  native: #01 pc 0000000000014d48  /system/lib64/libutils.so (android::Looper::pollInner(int)+148)  native: #02 pc 0000000000014c18  /system/lib64/libutils.so (android::Looper::pollOnce(int, int*, int*, void**)+60)  native: #03 pc 00000000001275f4  /system/lib64/libandroid_runtime.so (android::android_os_MessageQueue_nativePollOnce(_JNIEnv*, _jobject*, long, int)+44)  at android.os.MessageQueue.nativePollOnce(Native method)  at android.os.MessageQueue.next(MessageQueue.java:330)  at android.os.Looper.loop(Looper.java:169)  at android.app.ActivityThread.main(ActivityThread.java:7073)  at java.lang.reflect.Method.invoke(Native method)  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:536)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:876)

主线程闲暇,因为它正处于 nativePollOnce,正在期待新音讯。处于这个状态还产生了 ANR,可能有2个起因:

  • dump 堆栈机会太晚了,ANR 曾经产生过了,才去 dump 堆栈,此时主线程曾经恢复正常了
  • CPU 抢占或者内存缓和等其余因素引起

遇到这种状况,要先去剖析 CPU、内存的应用状况。其次能够关注抓取日志的工夫和 ANR 产生的工夫是否相隔太久,工夫太久这个堆栈就没有剖析的意义了。

主线程执行耗时操作
suspend all histogram:    Sum: 206us 99% C.I. 0.098us-46us Avg: 7.629us Max: 46usDALVIK THREADS (16):"main" prio=5 tid=1 Runnable  | group="main" sCount=0 dsCount=0 flags=0 obj=0x73907540 self=0x725f010800  | sysTid=32298 nice=-10 cgrp=default sched=1073741825/2 handle=0x72e60080d0  | state=R schedstat=( 6746757297 5887495 256 ) utm=670 stm=4 core=6 HZ=100  | stack=0x7fca180000-0x7fca182000 stackSize=8192KB  | held mutexes= "mutator lock"(shared held)  at com.xfhy.watchsignaldemo.MainActivity.makeAnr(MainActivity.kt:58)  at java.lang.reflect.Method.invoke(Native method)  at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:441)  at android.view.View.performClick(View.java:7317)  at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1219)  at android.view.View.performClickInternal(View.java:7291)  at android.view.View.access$3600(View.java:838)  at android.view.View$PerformClick.run(View.java:28247)  at android.os.Handler.handleCallback(Handler.java:900)  at android.os.Handler.dispatchMessage(Handler.java:103)  at android.os.Looper.loop(Looper.java:219)  at android.app.ActivityThread.main(ActivityThread.java:8668)  at java.lang.reflect.Method.invoke(Native method)  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1109)

主线程处于执行状态,不是闲暇状态,导致 ANR 了,阐明com.xfhy.watchsignaldemo.MainActivity.makeAnr有耗时操作。

主线程被锁阻塞
"main" prio=5 tid=1 Blocked  | group="main" sCount=1 dsCount=0 flags=1 obj=0x73907540 self=0x725f010800  | sysTid=19900 nice=-10 cgrp=default sched=0/0 handle=0x72e60080d0  | state=S schedstat=( 542745832 9516666 182 ) utm=48 stm=5 core=4 HZ=100  | stack=0x7fca180000-0x7fca182000 stackSize=8192KB  | held mutexes=  at com.xfhy.watchsignaldemo.MainActivity.makeAnr(MainActivity.kt:59)  - waiting to lock <0x0c6f8c52> (a java.lang.Object) held by thread 22   //正文1  - locked <0x01abeb23> (a java.lang.Object)  at java.lang.reflect.Method.invoke(Native method)  at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:441)  at android.view.View.performClick(View.java:7317)  at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1219)  at android.view.View.performClickInternal(View.java:7291)  at android.view.View.access$3600(View.java:838)  at android.view.View$PerformClick.run(View.java:28247)  at android.os.Handler.handleCallback(Handler.java:900)  at android.os.Handler.dispatchMessage(Handler.java:103)  at android.os.Looper.loop(Looper.java:219)  at android.app.ActivityThread.main(ActivityThread.java:8668)  at java.lang.reflect.Method.invoke(Native method)  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1109)"卧槽" prio=5 tid=22 Blocked  //正文2  | group="main" sCount=1 dsCount=0 flags=1 obj=0x12c8a118 self=0x71d625f800  | sysTid=20611 nice=0 cgrp=default sched=0/0 handle=0x71d4513d50  | state=S schedstat=( 486459 0 3 ) utm=0 stm=0 core=4 HZ=100  | stack=0x71d4411000-0x71d4413000 stackSize=1039KB  | held mutexes=  at com.xfhy.watchsignaldemo.MainActivity$makeAnr$1.invoke(MainActivity.kt:52)  - waiting to lock <0x01abeb23> (a java.lang.Object) held by thread 1  - locked <0x0c6f8c52> (a java.lang.Object)    at com.xfhy.watchsignaldemo.MainActivity$makeAnr$1.invoke(MainActivity.kt:49)  at kotlin.concurrent.ThreadsKt$thread$thread$1.run(Thread.kt:30)......

其中:

"main" prio=5 tid=1 Blocked  - waiting to lock <0x0c6f8c52> (a java.lang.Object) held by thread 22  - locked <0x01abeb23> (a java.lang.Object)"卧槽" prio=5 tid=22 Blocked  - waiting to lock <0x01abeb23> (a java.lang.Object) held by thread 1  - locked <0x0c6f8c52> (a java.lang.Object) 

主线程的 tid 是1,线程状态是 Blocked,正在期待0x0c6f8c52这个 Object,而这个 Object 被 thread 22这个线程所持有,主线程以后持有的是0x01abeb23的锁。而卧槽的tid是22,也是 Blocked 状态,它想申请的和已有的锁刚好与主线程相同。这样的话,ANR起因也就找到了。线程22持有了一把锁,并且始终不开释,主线程期待这把锁产生超时。在线上环境,常见因锁而 ANR 的场景是 SharePreference 写入。

CPU被抢占
CPU usage from 0ms to 10625ms later (2020-03-09 14:38:31.633 to 2020-03-09 14:38:42.257):  543% 2045/com.test.demo: 54% user + 89% kernel / faults: 4608 minor 1 major //留神看这里  99% 674/android.hardware.camera.provider@2.4-service: 81% user + 18% kernel / faults: 403 minor  24% 32589/com.wang.test: 22% user + 1.4% kernel / faults: 7432 minor 1 major  ......

该过程占据 CPU 高达543%,抢占了大部分 CPU 资源,因为导致产生 ANR,这种 ANR 通常与 App 无关。

内存缓和导致ANR
10-31 22:37:19.749 20733 20733 E Runtime : onTrimMemory level:80,pid:com.xxx.xxx:Launcher010-31 22:37:33.458 20733 20733 E Runtime : onTrimMemory level:80,pid:com.xxx.xxx:Launcher010-31 22:38:00.153 20733 20733 E Runtime : onTrimMemory level:80,pid:com.xxx.xxx:Launcher010-31 22:38:58.731 20733 20733 E Runtime : onTrimMemory level:80,pid:com.xxx.xxx:Launcher010-31 22:39:02.816 20733 20733 E Runtime : onTrimMemory level:80,pid:com.xxx.xxx:Launcher0

如果一份 ANR 日志的 CPU 和堆栈都很失常,能够思考是内存缓和。看一下 ANR 日志外面的内存相干局部。还能够去日志外面搜一下 onTrimMemory,如果 dump ANR 日志的工夫左近有相干日志,可能是内存比拟缓和了。

零碎服务超时导致ANR
"main" prio=5 tid=1 Native  | group="main" sCount=1 dsCount=0 flags=1 obj=0x727851e8 self=0x78d7060e00  | sysTid=4894 nice=0 cgrp=default sched=0/0 handle=0x795cc1e9a8  | state=S schedstat=( 8292806752 1621087524 7167 ) utm=707 stm=122 core=5 HZ=100  | stack=0x7febb64000-0x7febb66000 stackSize=8MB  | held mutexes=  kernel: __switch_to+0x90/0xc4  kernel: binder_thread_read+0xbd8/0x144c  kernel: binder_ioctl_write_read.constprop.58+0x20c/0x348  kernel: binder_ioctl+0x5d4/0x88c  kernel: do_vfs_ioctl+0xb8/0xb1c  kernel: SyS_ioctl+0x84/0x98  kernel: cpu_switch_to+0x34c/0x22c0  native: #00 pc 000000000007a2ac  /system/lib64/libc.so (__ioctl+4)  native: #01 pc 00000000000276ec  /system/lib64/libc.so (ioctl+132)  native: #02 pc 00000000000557d4  /system/lib64/libbinder.so (android::IPCThreadState::talkWithDriver(bool)+252)  native: #03 pc 0000000000056494  /system/lib64/libbinder.so (android::IPCThreadState::waitForResponse(android::Parcel*, int*)+60)  native: #04 pc 00000000000562d0  /system/lib64/libbinder.so (android::IPCThreadState::transact(int, unsigned int, android::Parcel const&, android::Parcel*, unsigned int)+216)  native: #05 pc 000000000004ce1c  /system/lib64/libbinder.so (android::BpBinder::transact(unsigned int, android::Parcel const&, android::Parcel*, unsigned int)+72)  native: #06 pc 00000000001281c8  /system/lib64/libandroid_runtime.so (???)  native: #07 pc 0000000000947ed4  /system/framework/arm64/boot-framework.oat (Java_android_os_BinderProxy_transactNative__ILandroid_os_Parcel_2Landroid_os_Parcel_2I+196)  at android.os.BinderProxy.transactNative(Native method) ————————————————要害行!!!  at android.os.BinderProxy.transact(Binder.java:804)  at android.net.IConnectivityManager$Stub$Proxy.getActiveNetworkInfo(IConnectivityManager.java:1204)—要害行!  at android.net.ConnectivityManager.getActiveNetworkInfo(ConnectivityManager.java:800)  at com.xiaomi.NetworkUtils.getNetworkInfo(NetworkUtils.java:2)  at com.xiaomi.frameworkbase.utils.NetworkUtils.getNetWorkType(NetworkUtils.java:1)  at com.xiaomi.frameworkbase.utils.NetworkUtils.isWifiConnected(NetworkUtils.java:1)

零碎服务超时个别会蕴含 BinderProxy.transactNative 关键字。
从日志堆栈中能够看到是获取网络信息产生了 ANR:getActiveNetworkInfo。零碎的服务都是 Binder 机制(16个线程),服务能力也是无限的,有可能零碎服务长时间不响应导致 ANR。如果其余利用占用了所有 Binder 线程,那么以后利用只能期待。可进一步搜寻 blockUntilThreadAvailable 关键字,at android.os.Binder.blockUntilThreadAvailable(Native method)。
如果有发现某个线程的堆栈,蕴含此字样,可进一步看其堆栈,确定是调用了什么零碎服务。此类ANR也是属于零碎环境的问题,如果某类型手机上频繁产生此问题,应用层能够思考躲避策略。

参考

https://mp.weixin.qq.com/s/qQ...
https://xfhy666.blog.csdn.net...