Android系统调试(01)日志分析基础流程

该系列文章总纲链接:专题分纲目录 Android系统基础


1 获取日志基本信息

通过DDMS来看log,一般在如下几种情况会产生关键log 。

  1. 程序异常退出 , uncaused exception
  2. 程序强制关闭 ,Force Closed (简称FC)
  3. 程序无响应 , Application No Response (简称ANR) , 顺便,一般主线程超过5秒么有处理就会ANR
  4. 手动生成 。

拿到一个日志文件,要分成多段来看 。 log文件很长,其中包含十几个小单元信息,但实际上他主要由三大块儿组成:

@1,系统基本信息 ,包括 内存,CPU ,进程队列 ,虚拟内存 , 垃圾回收等信息 。

------ MEMORY INFO (/proc/meminfo) ------
------ CPU INFO (top -n 1 -d 1 -m 30 -t) ------
------ PROCRANK (procrank) ------
------ VIRTUAL MEMORY STATS (/proc/vmstat) ------
------ VMALLOC INFO (/proc/vmallocinfo) ------

格式如下:

------ MEMORY INFO (/proc/meminfo) ------
MemTotal:         347076 kB
MemFree:           56408 kB
Buffers:            7192 kB
Cached:           104064 kB
SwapCached:            0 kB
Active:           192592 kB
Inactive:          40548 kB
Active(anon):     129040 kB
Inactive(anon):     1104 kB
Active(file):      63552 kB
Inactive(file):    39444 kB
Unevictable:        7112 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                44 kB
Writeback:             0 kB
AnonPages:        129028 kB
Mapped:            73728 kB
Shmem:              1148 kB
Slab:              13072 kB
SReclaimable:       4564 kB
SUnreclaim:         8508 kB
KernelStack:        3472 kB
PageTables:        12172 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:      173536 kB
Committed_AS:    7394524 kB
VmallocTotal:     319488 kB
VmallocUsed:       90752 kB
VmallocChunk:     181252 kB

@2 时间信息 , 也是我们主要分析的信息 。

------ VMALLOC INFO (/proc/vmallocinfo) ------
------ EVENT INFO (/proc/vmallocinfo) ------

格式如下:

------ SYSTEM LOG (logcat -b system -v time -d *:v) ------
01-15 16:41:43.671 W/PackageManager( 2466): Unknown permission com.wsomacp.permission.PROVIDER in package com.android.mms
01-15 16:41:43.671 I/ActivityManager( 2466): Force stopping package com.android.mms uid=10092
01-15 16:41:43.675 I/UsageStats( 2466): Something wrong here, didn't expect com.sec.android.app.twlauncher to be paused
01-15 16:41:44.108 I/ActivityManager( 2466): Start proc com.sec.android.widgetapp.infoalarm for service com.sec.android.widgetapp.infoalarm/.engine.DataService: pid=20634 uid=10005 gids={3003, 1015, 3002}
01-15 16:41:44.175 W/ActivityManager( 2466): Activity pause timeout for HistoryRecord{48589868 com.sec.android.app.twlauncher/.Launcher}
01-15 16:41:50.864 I/KeyInputQueue( 2466): Input event
01-15 16:41:50.866 D/KeyInputQueue( 2466): screenCaptureKeyFlag setting 0
01-15 16:41:50.882 I/PowerManagerService( 2466): Ulight 0->7|0
01-15 16:41:50.882 I/PowerManagerService( 2466): Setting target 2: cur=0.0 target=70 delta=4.6666665 nominalCurrentValue=0
01-15 16:41:50.882 I/PowerManagerService( 2466): Scheduling light animator!
01-15 16:41:51.706 D/PowerManagerService( 2466): enableLightSensor true
01-15 16:41:51.929 I/KeyInputQueue( 2466): Input event
01-15 16:41:51.933 W/WindowManager( 2466): No focus window, dropping: KeyEvent{action=0 code=26 repeat=0 meta=0 scancode=26 mFlags=9}

@3,虚拟机信息 , 包括进程的,线程的跟踪信息,这是用来跟踪进程和线程具体点的好地方 。 

------ VM TRACES JUST NOW (/data/anr/traces.txt.bugreport: 2017-01-15 16:49:02) ------
------ VM TRACES AT LAST ANR (/data/anr/traces.txt: 2017-01-15 16:49:02) ------

格式如下 :

----- pid 21161 at 2017-01-15 16:49:01 -----
Cmd line: com.android.mms
​
DALVIK THREADS:
"main" prio=5 tid=1 NATIVE
  | group="main" sCount=1 dsCount=0 s=N obj=0x4001d8d0 self=0xccc8
  | sysTid=21161 nice=0 sched=0/0 cgrp=default handle=-1345017808
  | schedstat=( 4151552996 5342265329 10995 )
  at android.media.MediaPlayer._reset(Native Method)
  at android.media.MediaPlayer.reset(MediaPlayer.java:1218)
  at android.widget.VideoView.release(VideoView.java:499)
  at android.widget.VideoView.access$2100(VideoView.java:50)
  at android.widget.VideoView$6.surfaceDestroyed(VideoView.java:489)
  at android.view.SurfaceView.reportSurfaceDestroyed(SurfaceView.java:572)
  at android.view.SurfaceView.updateWindow(SurfaceView.java:476)
  at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:206)
  at android.view.View.dispatchDetachedFromWindow(View.java:6082)
  at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1156)
  at android.view.ViewGroup.removeAllViewsInLayout(ViewGroup.java:2296)
  at android.view.ViewGroup.removeAllViews(ViewGroup.java:2254)
  at com.android.mms.ui.SlideView.reset(SlideView.java:687)
  at com.android.mms.ui.SlideshowPresenter.presentSlide(SlideshowPresenter.java:189)
  at com.android.mms.ui.SlideshowPresenter$3.run(SlideshowPresenter.java:531)
  at android.os.Handler.handleCallback(Handler.java:587)
  at android.os.Handler.dispatchMessage(Handler.java:92)
  at android.os.Looper.loop(Looper.java:123)
  at android.app.ActivityThread.main(ActivityThread.java:4627)
  at java.lang.reflect.Method.invokeNative(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:521)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  at dalvik.system.NativeStart.main(Native Method)

2 日志分析总结说明,观察与分析log文件的基本步骤(实例)

  1. 如果是ANR问题 , 则搜索“ANR”关键词 。 快速定位到关键事件信息 。
  2. 如果是ForceClosed 和其它异常退出信息,则搜索"Fatal" 关键词, 快速定位到关键事件信息 。
  3. 定位到关键事件信息后 , 如果信息不够明确的,再去搜索应用程序包虚拟机信息 ,查看具体的进程和线程跟踪的日志,定位到代码 。 

用这种方法,出现问题,根本不需要断点调试 , 直接定位到问题,屡试不爽。下面,我们就开始来分析这个例子的log;打开log文件 , 由于是ANR错误,因此搜索"ANR " (加空格是为了屏蔽掉不少保存到anr.log文件的无效信息),定位到关键的事件信息如下:

01-15 16:49:02.433 E/ActivityManager( 2466): ANR in com.android.mms (com.android.mms/.ui.SlideshowActivity)
01-15 16:49:02.433 E/ActivityManager( 2466): Reason: keyDispatchingTimedOut
01-15 16:49:02.433 E/ActivityManager( 2466): Load: 0.6 / 0.61 / 0.42 
//5分钟,10分钟,15分钟内的平均负载分别为:0.6 , 0.61 , 0.42
01-15 16:49:02.433 E/ActivityManager( 2466): CPU usage from 1337225ms to 57ms ago:
01-15 16:49:02.433 E/ActivityManager( 2466):   sensorserver_ya: 8% = 0% user + 8% kernel / faults: 40 minor
......
01-15 16:49:02.433 E/ActivityManager( 2466):  -com.android.mms: 0% = 0% user + 0% kernel
01-15 16:49:02.433 E/ActivityManager( 2466):  -flush-179:8: 0% = 0% user + 0% kernel
01-15 16:49:02.433 E/ActivityManager( 2466): TOTAL: 25% = 10% user + 14% kernel + 0% iowait + 0% irq + 0% softirq
01-15 16:49:02.436 I/        ( 2466): dumpmesg > "/data/log/dumpstate_app_anr.log"

在这里我们大概知道问题是什么了,结合我们之前的操作流程,我们知道问题是在点击按钮某时候可能处理不过来按钮事件,导致超时无响应 。 我们知道Activity中是通过重载dispatchTouchEvent(MotionEvent ev)来处理点击屏幕事件 。 然后我们可以顺藤摸瓜,这时候发现多个IO操作的地方都在主线程中,可能引起问题,但不好判断到底是哪个  ,我们目前掌握的信息还不够 。 于是我们再分析虚拟机信息 , 搜索“Dalvik Thread”关键词,快速定位到本应用程序的虚拟机信息日志,如下:

----- pid 2922 at 2017-01-13 13:51:07 -----
Cmd line: com.android.mms
​
DALVIK THREADS:
"main" prio=5 tid=1 NATIVE
  | group="main" sCount=1 dsCount=0 s=N obj=0x4001d8d0 self=0xccc8
  | sysTid=2922 nice=0 sched=0/0 cgrp=default handle=-1345017808
  | schedstat=( 3497492306 15312897923 10358 )
  at android.media.MediaPlayer._release(Native Method)
  at android.media.MediaPlayer.release(MediaPlayer.java:1206)
  at android.widget.VideoView.stopPlayback(VideoView.java:196)
  at com.android.mms.ui.SlideView.stopVideo(SlideView.java:640)
  at com.android.mms.ui.SlideshowPresenter.presentVideo(SlideshowPresenter.java:443)
  at com.android.mms.ui.SlideshowPresenter.presentRegionMedia(SlideshowPresenter.java:219)
  at com.android.mms.ui.SlideshowPresenter$4.run(SlideshowPresenter.java:516)
  at android.os.Handler.handleCallback(Handler.java:587)
  at android.os.Handler.dispatchMessage(Handler.java:92)
  at android.os.Looper.loop(Looper.java:123)
  at android.app.ActivityThread.main(ActivityThread.java:4627)
  at java.lang.reflect.Method.invokeNative(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:521)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  at dalvik.system.NativeStart.main(Native Method)
​
"Binder Thread #3" prio=5 tid=11 NATIVE
  | group="main" sCount=1 dsCount=0 s=N obj=0x4837f808 self=0x242280
  | sysTid=3239 nice=0 sched=0/0 cgrp=default handle=2341032
  | schedstat=( 32410506 932842514 164 )
  at dalvik.system.NativeStart.run(Native Method)
​
"AsyncQueryWorker" prio=5 tid=9 WAIT
  | group="main" sCount=1 dsCount=0 s=N obj=0x482f4b80 self=0x253e10
  | sysTid=3236 nice=0 sched=0/0 cgrp=default handle=2432120
  | schedstat=( 3225061 26561350 27 )
  at java.lang.Object.wait(Native Method)
  - waiting on <0x482f4da8> (a android.os.MessageQueue)
  at java.lang.Object.wait(Object.java:288)
  at android.os.MessageQueue.next(MessageQueue.java:146)
  at android.os.Looper.loop(Looper.java:110)
  at android.os.HandlerThread.run(HandlerThread.java:60)
​
"Thread-9" prio=5 tid=8 WAIT
  | group="main" sCount=1 dsCount=0 s=N obj=0x4836e2b0 self=0x25af70
  | sysTid=2929 nice=0 sched=0/0 cgrp=default handle=2370896
  | schedstat=( 130248 4389035 2 )
  at java.lang.Object.wait(Native Method)
  - waiting on <0x4836e240> (a java.util.ArrayList)
  at java.lang.Object.wait(Object.java:288)
  at com.android.mms.data.Contact$ContactsCache$TaskStack$1.run(Contact.java:488)
  at java.lang.Thread.run(Thread.java:1096)
​
"Binder Thread #2" prio=5 tid=7 NATIVE
  | group="main" sCount=1 dsCount=0 s=N obj=0x482f8ca0 self=0x130fd0
  | sysTid=2928 nice=0 sched=0/0 cgrp=default handle=1215968
  | schedstat=( 40610049 1837703846 195 )
  at dalvik.system.NativeStart.run(Native Method)
​
"Binder Thread #1" prio=5 tid=6 NATIVE
  | group="main" sCount=1 dsCount=0 s=N obj=0x482f4a78 self=0x128a50
  | sysTid=2927 nice=0 sched=0/0 cgrp=default handle=1201352
  | schedstat=( 40928066 928867585 190 )
  at dalvik.system.NativeStart.run(Native Method)
​
"Compiler" daemon prio=5 tid=5 VMWAIT
  | group="system" sCount=1 dsCount=0 s=N obj=0x482f1348 self=0x118960
  | sysTid=2926 nice=0 sched=0/0 cgrp=default handle=1149216
  | schedstat=( 753021350 3774113668 6686 )
  at dalvik.system.NativeStart.run(Native Method)
​
"JDWP" daemon prio=5 tid=4 VMWAIT
  | group="system" sCount=1 dsCount=0 s=N obj=0x482f12a0 self=0x132940
  | sysTid=2925 nice=0 sched=0/0 cgrp=default handle=1255680
  | schedstat=( 2827103 29553323 19 )
  at dalvik.system.NativeStart.run(Native Method)
​
"Signal Catcher" daemon prio=5 tid=3 RUNNABLE
  | group="system" sCount=0 dsCount=0 s=N obj=0x482f11e8 self=0x135988
  | sysTid=2924 nice=0 sched=0/0 cgrp=default handle=1173688
  | schedstat=( 11793815 12456169 7 )
  at dalvik.system.NativeStart.run(Native Method)
​
"HeapWorker" daemon prio=5 tid=2 VMWAIT
  | group="system" sCount=1 dsCount=0 s=N obj=0x45496028 self=0x135848
  | sysTid=2923 nice=0 sched=0/0 cgrp=default handle=1222608
  | schedstat=( 79049792 1520840200 95 )
  at dalvik.system.NativeStart.run(Native Method)
​
----- end 2922 -----

每一段都是一个线程 ,当然我们还是看线程号为1的主线程了。通过分析发现关键问题是这样:

at com.android.mms.ui.SlideshowPresenter$3.run(SlideshowPresenter.java:531)

定位到代码:

mHandler.post(new Runnable() {
    public void run() {
        try {
            presentRegionMedia(view, (RegionMediaModel) model, dataChanged);
        } catch (OMADRMException e) {
            Log.e(TAG, e.getMessage(), e);
            Toast.makeText(mContext,
                    mContext.getString(R.string.insufficient_drm_rights),
                    Toast.LENGTH_SHORT).show();
        } catch (IOException e){
            Log.e(TAG, e.getMessage(), e);
            Toast.makeText(mContext,
                    mContext.getString(R.string.insufficient_drm_rights),
                    Toast.LENGTH_SHORT).show();
        
        }
    }
}

这就很清楚了, Handler.post 方法之后执行时间太长的问题 。 继续看presentRegionMedia(view, (RegionMediaModel) model, dataChanged) 这个方法 , 发现最终是调用的framework 中MediaPlayer.stop 方法 。至此日志分析告一段落 。 

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