我从 App Store 中已有的应用程序中获得了崩溃日志。崩溃日志的奇怪之处在于，一个类方法在崩溃线程的回溯中出现了两次，就好像该类方法递归地调用了自己一样。我说很奇怪，因为该类方法非常简单，并且它不会在方法体内进行递归调用。这是崩溃日志中的一部分：
Exception Type: EXC_BAD_ACCESS (SIGABRT)
Exception Codes: KERN_INVALID_ADDRESS at 0x00000000
Crashed Thread: 0
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x3b788350 __pthread_kill + 8
1 libsystem_c.dylib 0x3b6fefb2 pthread_kill + 54
2 libsystem_c.dylib 0x3b73b366 abort + 90
3 btg2 0x0172a358 ___lldb_unnamed_function128645$$btg2 + 280
4 btg2 0x0171af34 ___lldb_unnamed_function128478$$btg2 + 256
5 libsystem_c.dylib 0x3b708d38 _sigtramp + 40
6 btg2 0x0129fd7c +[PHAPIRequest expectedSignatureValueForResponse:nonce:secret:] (PHAPIRequest.m:129)
7 btg2 0x0129fd7c +[PHAPIRequest expectedSignatureValueForResponse:nonce:secret:] (PHAPIRequest.m:129)
8 btg2 0x012a1ee4 -[PHAPIRequest connectionDidFinishLoadingWithRequest:response:data:context:] (PHAPIRequest.m:501)
9 btg2 0x012aee04 -[PHConnectionManager connectionDidFinishLoading:] (PHConnectionManager.m:234)
10 Foundation 0x33d46912 __65-[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:]_block_invoke_0 + 14
11 Foundation 0x33c86764 -[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:] + 196
12 Foundation 0x33c86680 -[NSURLConnectionInternal _withActiveConnectionAndDelegate:] + 56
13 CFNetwork 0x330e764c ___delegate_didFinishLoading_block_invoke_0 + 24
14 CFNetwork 0x330e6d30 ___withDelegateAsync_block_invoke_0 + 52
15 CFNetwork 0x3310f010 ___performAsync_block_invoke_068 + 16
16 CoreFoundation 0x33350aca CFArrayApplyFunction + 174
17 CFNetwork 0x3310f46e RunloopBlockContext::perform() + 70
18 CFNetwork 0x3307345e MultiplexerSource::perform() + 186
19 CoreFoundation 0x333df8f4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 12
20 CoreFoundation 0x333df158 __CFRunLoopDoSources0 + 208
21 CoreFoundation 0x333ddf2a __CFRunLoopRun + 642
22 CoreFoundation 0x33351238 CFRunLoopRunSpecific + 352
23 CoreFoundation 0x333510c4 CFRunLoopRunInMode + 100
24 GraphicsServices 0x36f0c336 GSEventRunModal + 70
25 UIKit 0x3526d2b4 UIApplicationMain + 1116
26 btg2 0x0007da00 main (main.mm:21)
27 btg2 0x0007a504 ___lldb_unnamed_function1$$btg2 + 36
有没有人知道为什么 +[PHAPIRequest expectedSignatureValueForResponse:nonce:secret:] 在回溯中出现两次或者可能知道崩溃的原因？感谢你的帮助！