Question

我们从flutter应用程序的Testflight发行版中得到了一些崩溃信息。由于崩溃日志告诉我们的信息很少，因此我们很难查明问题出在哪里。

以下是日志（gist of full crash log / Xcode screenshot）：

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x00000003b3801090
VM Region Info: 0x3b3801090 is not in any region.  Bytes after previous region: 4622127249  
      REGION TYPE                      START - END             [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      MALLOC_NANO            0000000280000000-00000002a0000000 [512.0M] rw-/rwx SM=PRV  
--->  
      UNUSED SPACE AT END

Termination Signal: Segmentation fault: 11
Termination Reason: Namespace SIGNAL, Code 0xb
Terminating Process: exc handler [4572]
Triggered by Thread:  0

Thread 0 name:
Thread 0 Crashed:
0   libobjc.A.dylib                 0x000000018a902090 objc_msgSend + 16
1   Flutter                         0x00000001009d6f4c -[SemanticsObject hasChildren] + 60 (accessibility_bridge.mm:160)
2   Flutter                         0x00000001009d8334 -[SemanticsObject accessibilityContainer] + 36 (accessibility_bridge.mm:287)
3   UIAccessibility                 0x0000000195f88898 -[NSObject(AXPrivCategory) _accessibilityParentView] + 84 (NSObjectAccessibility.m:7787)
4   UIAccessibility                 0x0000000195f88734 -[NSObject(AXPrivCategory) _accessibilityWindow] + 92 (NSObjectAccessibility.m:7762)
5   UIAccessibility                 0x0000000195f8ff68 -[NSObject(AXPrivCategory) _accessibilityConvertSystemBoundedScreenRectToContextSpace:] + 48 (NSObjectAccessibility.m:10192)
6   UIAccessibility                 0x0000000195f83ee8 -[NSObject(AXPrivCategory) _iosAccessibilityAttributeValue:] + 4624 (NSObjectAccessibility.m:5303)
7   UIAccessibility                 0x0000000195f6637c _copyMultipleAttributeValuesCallback + 540 (UIAccessibilityRuntime.m:345)
8   AXRuntime                       0x0000000194fc56e0 ___AXXMIGCopyMultipleAttributeValues_block_invoke + 60 (AccessibilityPriv.m:1262)
9   AXRuntime                       0x0000000194fc5264 _handleNonMainThreadCallback + 60 (AccessibilityPriv.m:466)
10  AXRuntime                       0x0000000194fc5570 _AXXMIGCopyMultipleAttributeValues + 332 (AccessibilityPriv.m:1261)
11  AXRuntime                       0x0000000194fbf4b4 _XCopyMultipleAttributeValues + 392 (AccessibilityClientDefsServer.c:1354)
12  AXRuntime                       0x0000000194fd443c mshMIGPerform + 268 (MachServerHelper.c:447)
13  CoreFoundation                  0x000000018ab5d07c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 56 (CFRunLoop.c:1937)
14  CoreFoundation                  0x000000018ab5c7a8 __CFRunLoopDoSource1 + 444 (CFRunLoop.c:2075)
15  CoreFoundation                  0x000000018ab5767c __CFRunLoopRun + 2168 (CFRunLoop.c:3098)
16  CoreFoundation                  0x000000018ab56adc CFRunLoopRunSpecific + 464 (CFRunLoop.c:3192)
17  GraphicsServices                0x0000000194adc328 GSEventRunModal + 104 (GSEvent.c:2246)
18  UIKitCore                       0x000000018ec51ae0 UIApplicationMain + 1936 (UIApplication.m:4773)
19  Runner                          0x0000000100666cec main + 96 (AppDelegate.swift:5)
20  libdyld.dylib                   0x000000018a9e0360 start + 4

我们已按照本指南https://github.com/flutter/flutter/wiki/Crashes试图进一步表示日志。使用以下步骤：

获取我们的Flutter Engine版本
为我们的Flutter.framework版本下载正确的dSYM文件
尝试用以下符号表示：

export DEVELOPER_DIR="/Applications/Xcode.app/Contents/Developer"

cp -i /Applications/Xcode.app/Contents/SharedFrameworks/DVTFoundation.framework/Versions/A/Resources/symbolicatecrash ./

symbolicatecrash 2020-01-11.crash Flutter.dSYM > symbolicated.crash

但是它并没有真正改善，请参见更改in this gist

有关从何处开始查找导致此类崩溃的编程错误的任何提示。我们正在寻找有关在一般情况下以及在这种情况下调试内部抖动崩溃的两种技巧。

此外，由于我们不知道在哪里查看，所以我们无法重现此崩溃。

Answer 1

根据您的崩溃报告VM Region Info: 0x3b3801090 is not in any region.，崩溃可能是由于正在访问未分配的内存而发生的。。。这可能是因为从主线程外部调用___AXXMIGCopyMultipleAttributeValues_block_invoke（看起来像到堆栈跟踪）。但是我不知道您是否可以调试lib AXRuntime。

您是否尝试在Xcode中使用查看日志窗口来符号化崩溃报告？（您必须拥有物理iphone X（iphone10），以免架构在过程中迷路。此page可能会有所帮助。

如何调试Flutter iOS崩溃

1 个答案: