iOS Crash分析

SDK维护涉及2方面工作：1.排查crash是否是SDK引起 2.根据crash信息解决bug。主要思路：先识别常见模式，然后再具体分析。

Crash 类型

singal全部类型可#import <sys/signal.h>点进去查看。常见类型见 Apple官方 或 译文

识别常见Crash模式

apple官方文档

• Swift Runtime Error：

Exception Type:  EXC_BREAKPOINT (SIGTRAP)
...
Termination Signal: Trace/BPT trap: 5
Termination Reason: Namespace SIGNAL, Code 0x5
...
Thread 0 Crashed:
0   MyCoolApp                         0x0000000100a71a88 @objc ViewController.viewDidLoad() (in MyCoolApp) (ViewController.swift:18)

• Language Exception

// 数组越界
Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note:  EXC_CORPSE_NOTIFY
...
Last Exception Backtrace:
0   CoreFoundation                    0x19aae2a48 __exceptionPreprocess + 220
1   libobjc.A.dylib                   0x19a809fa4 objc_exception_throw + 55

• Watchdog

// 主要是 0x8badf00d
Exception Type:  EXC_CRASH (SIGKILL)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note:  EXC_CORPSE_NOTIFY
Termination Reason: Namespace SPRINGBOARD, Code 0x8badf00d

• Zombie objects

// 包含objc_msgSend或doesNotRecognizeSelector
Thread 0 Crashed:
0   libobjc.A.dylib                   0x00000001a186d190 objc_msgSend + 16
1   Foundation                        0x00000001a1f31238 __NSThreadPerformPerform + 232
2   CoreFoundation                    0x00000001a1ac67e0 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24

Last Exception Backtrace:
0   CoreFoundation                    0x1bf596a48 __exceptionPreprocess + 220
1   libobjc.A.dylib                   0x1bf2bdfa4 objc_exception_throw + 55
2   CoreFoundation                    0x1bf49a5a8 -[NSObject+ 193960 (NSObject) doesNotRecognizeSelector:] + 139

• Memory Access Issue

//类型EXC_BAD_ACCESS，并且有VM Region Info
Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000000
VM Region Info: 0 is not in any region.  Bytes before following region: 4307009536

      REGION TYPE                      START - END             [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      UNUSED SPACE AT START
--->
      __TEXT                 0000000100b7c000-0000000100b84000 [   32K] r-x/r-x SM=COW  ...pp/MyGreatApp

• Framework Missing

Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Termination Description: DYLD, dependent dylib '@rpath/MyFramework.framework/MyFramework'
    not found for '<path>/MyCoolApp.app/MyCoolApp', tried but didn't find: 
    '/usr/lib/swift/MyFramework.framework/MyFramework' 
    '<path>/MyCoolApp.app/Frameworks/MyFramework.framework/MyFramework' 
    '@rpath/MyFramework.framework/MyFramework' 
    '/System/Library/Frameworks/MyFramework.framework/MyFramework'

详细分析思路

https://developer.apple.com/documentation/xcode/analyzing-a-crash-report

参考：

iOS 了解和分析Crash Report-官方译文
iOS Crash分析模型
SIGKILL 初探