如何调试：应用程序中的JNI DETECTED ERROR：使用无效的jobject [英] How to debug: JNI DETECTED ERROR IN APPLICATION: use of invalid jobject
问题描述
我正在使用 Xamarin Android项目，我收到以下错误（完整日志这里）
I am working on a Xamarin Android project, and I get the following error (full log here)
11-07 08:28:09.067: A/art(7164): art/runtime/java_vm_ext.cc:410] JNI DETECTED ERROR IN APPLICATION: use of invalid jobject 0xd4fd90e0
11-07 08:28:09.067: A/art(7164): art/runtime/java_vm_ext.cc:410] "Thread-1973" prio=10 tid=26 Runnable
11-07 08:28:09.067: A/art(7164): art/runtime/java_vm_ext.cc:410] | group="main" sCount=0 dsCount=0 obj=0x137270a0 self=0xc89d4900
11-07 08:28:09.067: A/art(7164): art/runtime/java_vm_ext.cc:410] | sysTid=9034 nice=-11 cgrp=default sched=0/0 handle=0xd4b3a930
11-07 08:28:09.067: A/art(7164): art/runtime/java_vm_ext.cc:410] | state=R schedstat=( 310795035 15833156 94 ) utm=24 stm=7 core=5 HZ=100
11-07 08:28:09.067: A/art(7164): art/runtime/java_vm_ext.cc:410] | stack=0xd4a3c000-0xd4a3e000 stackSize=1022KB
11-07 08:28:09.067: A/art(7164): art/runtime/java_vm_ext.cc:41n0] | held mutexes= "mutator lock"(shared held)
尝试播放电影时（自定义第三方）飞行模式下的ExoPlayer包装库。我没有寻求帮助只用这个信息找到错误，但只是一种调试应用程序的方法。出现崩溃时，调试器将断开连接。
when try to play a movie (custom third party ExoPlayer wrapper library) while in airplane mode. I am not seeking help to find the bug with only this info, but only a way to debug app. When crash appears the debugger is disconnected.
我也见过这个帖子： https://bugzilla.xamarin.com/show_bug.cgi?id=45281
，但是当我使用以下内容启用GC日志时：
Also I have seen this thread: https://bugzilla.xamarin.com/show_bug.cgi?id=45281 on Xamarin bugzilla, but when I enable GC logs with the following:
$ adb shell setprop debug.mono.log gref,gc
应用程序不会崩溃!!!
the app does not crash!!!
我在设备上测试 Samsung SM-G930F aka Samsung S7 并使用 API级别23 。该错误也出现在其他设备上。
I am testing on device Samsung SM-G930F aka Samsung S7 and using API level 23. The error appears also on other devices.
我的构建设置：
Xamarin Studio Community
Version 6.1.1 (build 15)
Installation UUID: b3096ed4-0118-4e0d-87f4-a1fe79ffc301
Runtime:
Mono 4.6.1 (mono-4.6.0-branch-c8sr0/ef43c15) (64-bit)
GTK+ 2.24.23 (Raleigh theme)
Package version: 406010005
NuGet
Version: 3.4.3.0
Xamarin.Profiler
Not Installed
Apple Developer Tools
Xcode 8.1 (11544)
Build 8B62
Xamarin.Mac
Version: 2.10.0.105 (Xamarin Studio Community)
Xamarin.iOS
Version: 10.0.1.10 (Xamarin Studio Community)
Hash: ad1cd42
Branch: cycle8-sr0-xi
Build date: 2016-10-03 15:18:44-0400
Xamarin.Android
Version: 7.0.1.3 (Xamarin Studio Community)
Android SDK: /Users/andi/Library/Android/sdk
Supported Android versions:
5.0 (API level 21)
6.0 (API level 23)
7.0 (API level 24)
SDK Tools Version: 25.2.2
SDK Platform Tools Version: 24.0.3
SDK Build Tools Version: 23.0.1
Java SDK: /usr
java version "1.8.0_91"
Java(TM) SE Runtime Environment (build 1.8.0_91-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.91-b14, mixed mode)
Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL
Xamarin Android Player
Version: 0.6.5
Location: /Applications/Xamarin Android Player.app
Build Information
Release ID: 601010015
Git revision: fa52f02641726146e2589ed86ec4097fbe101888
Build date: 2016-09-22 08:03:02-04
Xamarin addins: 75d65712af93d54dc39ae4c42b21dfa574859fd6
Build lane: monodevelop-lion-cycle8-sr0
Operating System
Mac OS X 10.12.1
Darwin Pentagon.local 16.1.0 Darwin Kernel Version 16.1.0
Thu Oct 13 21:26:57 PDT 2016
root:xnu-3789.21.3~60/RELEASE_X86_64 x86_64
编辑：
启用gref日志（无崩溃）： https://gist.github.com/sanandrea / b9a837b8c885ac037c4f4bc6e8030d10
With gref enabled log (no crash): https://gist.github.com/sanandrea/b9a837b8c885ac037c4f4bc6e8030d10
未启用gref（崩溃）： https://gist.github.com/sanandrea/d2c5c895b4bc15f45381421c9c21b859
Without gref enabled (crash): https://gist.github.com/sanandrea/d2c5c895b4bc15f45381421c9c21b859
编辑2
可以标记为#HeisenBug
EDIT 2 This can be tagged as #HeisenBug
推荐答案
理想情况下，如何调试此类情况非常接近您所遵循的路径。
Ideally how you would debug this type of situation is very close to the path you are following.
您要做的第一件事是通过adb或 environment.txt 文件启用gref日志使用构建操作 AndroidEnvironment （注意：使用后者opti有一些限制on - https://developer.xamarin.com/guides/android/advanced_topics/环境/＃概述）：
The first thing that you'd want to do is enable gref logs via adb or an environment.txt file with a Build Action of AndroidEnvironment(Note: There are limitations using the latter option - https://developer.xamarin.com/guides/android/advanced_topics/environment/#Overview):
adb shell setprop debug.mono.log gref
太棒了！现在我们可以看到各个全局引用的生命周期（简称gref）。这是一个起点。为了将来参考这篇文章，让我们定义一些项目：
Great! Now we can see the lifetime of respective global references(gref for short). This is a starting point. For future reference in this post, let's define a few items:
- gref - 全球参考
- wref - 弱全局引用
理想情况下，我们希望在物理设备上测试它，因为它将具有~52000 grefs的限制。而模拟器的限制为2000 grefs。如你想象的那样，如果你很快就越过这条线（你可能会这样），这可能会非常麻烦。
Ideally we want to test this on a physical device as it will have a limit of ~52000 grefs. Whereas an emulator has a limit of 2000 grefs. As you imagine this can be quite troublesome if you cross this line quite quickly(Which you just might).
接下来我们可以遵循我们想要的四条主要信息的惯例了解：
Next we can follow the convention of four main messages we want to know about:
- 以
开始+ g +- gref creation - 以
开头-g -- gref destruction - 以
开头+ w +- wref creation - 以
-w开头 -- wref destruction
- Start with
+g+- gref creation - Start with
-g-- gref destruction - Start with
+w+- wref creation - Start with
-w-- wref destruction
您可能还注意到，在这些行上有一个 grefc 值。这是指 gref count ，这是Xamarin.Android所做的总量。然后，您可以假设 grefwc 值为 wref count 。让我们在一个小表中定义：
You might also notice that on these lines there is a grefc value. This refers to the gref count which is the total amount that Xamarin.Android has made. You can then assume the same for the grefwc value being the wref count. Let's define this in a small table:
-
grefc- gref count -
grefwc- wref count
grefc- gref countgrefwc- wref count
让'看一下这种语法的一个例子：
Let' take a look at an example of this syntax:
I/monodroid-gref(12405): +g+ grefc 108 gwrefc 0 obj-handle 0x40517468/L -> new-handle 0x40517468/L from at Java.Lang.Object.RegisterInstance(IJavaObject instance, IntPtr value, JniHandleOwnership transfer)
I/monodroid-gref(12405): at Java.Lang.Object.SetHandle(IntPtr value, JniHandleOwnership transfer)
I/monodroid-gref(12405): at Java.Lang.Object..ctor(IntPtr handle, JniHandleOwnership transfer)
I/monodroid-gref(12405): at Java.Lang.Thread+RunnableImplementor..ctor(System.Action handler, Boolean removable)
I/monodroid-gref(12405): at Java.Lang.Thread+RunnableImplementor..ctor(System.Action handler)
I/monodroid-gref(12405): at Android.App.Activity.RunOnUiThread(System.Action action)
I/monodroid-gref(12405): at Mono.Samples.Hello.HelloActivity.UseLotsOfMemory(Android.Widget.TextView textview)
I/monodroid-gref(12405): at Mono.Samples.Hello.HelloActivity.<OnCreate>m__3(System.Object o)
I/monodroid-gref(12405): handle 0x40517468; key_handle 0x40517468: Java Type: `mono/java/lang/RunnableImplementor`; MCW type: `Java.Lang.Thread+RunnableImplementor`
I/monodroid-gref(12405): Disposing handle 0x40517468
I/monodroid-gref(12405): -g- grefc 107 gwrefc 0 handle 0x40517468/L from at Java.Lang.Object.Dispose(System.Object instance, IntPtr handle, IntPtr key_handle, JObjectRefType handle_type)
I/monodroid-gref(12405): at Java.Lang.Object.Dispose()
I/monodroid-gref(12405): at Java.Lang.Thread+RunnableImplementor.Run()
I/monodroid-gref(12405): at Java.Lang.IRunnableInvoker.n_Run(IntPtr jnienv, IntPtr native__this)
I/monodroid-gref(12405): at System.Object.c200fe6f-ac33-441b-a3a0-47659e3f6750(IntPtr , IntPtr )
I/monodroid-gref(27679): +w+ grefc 1916 gwrefc 296 obj-handle 0x406b2b98/G -> new-handle 0xde68f4bf/W from take_weak_global_ref_jni
I/monodroid-gref(27679): -w- grefc 1915 gwrefc 294 handle 0xde691aaf/W from take_global_ref_jni
句柄或obj-handle值是JNI句柄值，'/'后面的字符是句柄值的类型：/ L用于本地引用，/ G用于全局引用，和/ W用于弱全局引用。
The handle or obj-handle value is the JNI handle value, and the character after the ' /' is the type of handle value: /L for local reference, /G for global references, and /W for weak global references.
现在让我们看一下各种场景记住这一点：
Now let's take a look into various scenarios with this note in mind:
# Java instance is created and wrapped by a MCW
I/monodroid-gref(27679): +g+ grefc 2211 gwrefc 0 obj-handle 0x4066df10/L -> new-handle 0x4066df10/L from ...
I/monodroid-gref(27679): handle 0x4066df10; key_handle 0x4066df10: Java Type: `android/graphics/drawable/TransitionDrawable`; MCW type: `Android.Graphics.Drawables.TransitionDrawable`
# A GC is being performed...
I/monodroid-gref(27679): +w+ grefc 1953 gwrefc 259 obj-handle 0x4066df10/G -> new-handle 0xde68f95f/W from take_weak_global_ref_jni
I/monodroid-gref(27679): -g- grefc 1952 gwrefc 259 handle 0x4066df10/G from take_weak_global_ref_jni
# Object is still alive, as handle != null
# wref turned back into a gref
I/monodroid-gref(27679): *try_take_global obj=0x4976f080 -> wref=0xde68f95f handle=0x4066df10
I/monodroid-gref(27679): +g+ grefc 1930 gwrefc 39 obj-handle 0xde68f95f/W -> new-handle 0x4066df10/G from take_global_ref_jni
I/monodroid-gref(27679): -w- grefc 1930 gwrefc 38 handle 0xde68f95f/W from take_global_ref_jni
# Object is dead, as handle == null
# wref is freed, no new gref created
I/monodroid-gref(27679): *try_take_global obj=0x4976f080 -> wref=0xde68f95f handle=0x0
I/monodroid-gref(27679): -w- grefc 1914 gwrefc 296 handle 0xde68f95f/W from take_global_ref_jni
您可以在 Xamarin.Android垃圾收集算法，以确切了解这些句柄何时发生变化。
You can see my other answer on the Xamarin.Android Garbage Collection Algorithm to see exactly when these handles get changed.
现在您已了解各种模式可以在各种模式中看到方案，它将帮助您弄清楚无效作业时发生的事情。
So now that you have an idea of what patterns you can see during various scenarios, it will help you figure out what is going on at the time of your invalid jobject.
现在是有趣的部分，但也可能是最困难的部分：
Now is the fun part, but also can be the hardest part:
现在，您需要在启用此日志记录时复制崩溃。
You need to now replicate the crash while this logging is enabled.
完成后，您需要收到收到的新错误消息和给您的句柄。在您的原始帖子中，它指的是：
Once you have done that, you need to take the new error message you received and the handle given to you. In your original post it refers to:
JNI DETECTED ERROR IN APPLICATION: use of invalid jobject 0xd4fd90e0
但是，这个句柄可能会在问题的不同复制过程中发生变化。但是，一旦你有句柄，就可以使用像 grep 搜索句柄字符串：
However it's possible that this handle will change throughout different replications of the issue. However once you have that handle, you can use a tool like grep to search for the handle string:
0xd4fd90e0
完成此操作后，您可以选择通过上面的示例代码段查看此句柄的状态，并在相应区域中进行修复。 （过早GC，手动处理对象等）
Once you've done this, you can take a look at what state this handle is in via the sample snippet above and make a fix in the respective area. (Premature GC, Object manually being disposed, etc)
这篇关于如何调试：应用程序中的JNI DETECTED ERROR：使用无效的jobject的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
