iPhone 应用程序在进入前台时崩溃

Question

我有一个通过附件端口与设备通信的应用程序。当设备向 iPhone 发送数据（以每 20 毫秒一个 13 字节数据包的速率，所以速度不是很快）时，如果我按主页按钮将应用程序发送到后台，然后再次打开它，它将崩溃。我在 UIApplicationDidBecomeActiveNotification 和 UIApplicationWillResignActiveNotification 中添加了监听器，以在应用程序进入后台时关闭数据传输，并在应用程序返回时重新打开它，现在它不会一直崩溃，而是不规律地崩溃。当它崩溃时，它甚至在发送 UIApplicationDidBecomeActiveNotification 之前就崩溃了。

这是错误的设备日志：

Exception Type:  EXC_BAD_ACCESS (SIGBUS)  
Exception Codes: KERN_PROTECTION_FAILURE at 0x00000004  
Crashed Thread:  3

Thread 0:  
0   libSystem.B.dylib               0x000016a8 semaphore_wait_trap + 8  
1   libSystem.B.dylib               0x0002ed9e semaphore_wait + 2  
2   libSystem.B.dylib               0x000d7ce4 _dispatch_semaphore_wait_slow + 296  
3   libSystem.B.dylib               0x000d64a0 _dispatch_barrier_sync_f_slow + 128  
4   CoreFoundation                  0x0001511e CFMachPortCreateRunLoopSource + 118  
5   QuartzCore                      0x00005466 CA::Context::client_port() + 78  
6   QuartzCore                      0x00005310 CA::Context::connect_remote() + 244  
7   QuartzCore                      0x00004fda -[CAContextImpl initRemoteWithOptions:] + 26  
8   QuartzCore                      0x00004f9c +[CAContext remoteContextWithOptions:] + 28  
9   UIKit                           0x0000dae0 -[UIWindow _createContext] + 532  
10  UIKit                           0x0015957e _UIWindowUpdateVisibleContextOrder + 98  
11  UIKit                           0x0015962a +[UIWindow _prepareWindowsForAppResume] + 10  
12  UIKit                           0x00152824 -[UIApplication _handleApplicationResumeEvent:] + 68  
13  UIKit                           0x0005da80 -[UIApplication handleEvent:withNewEvent:] + 3772  
14  UIKit                           0x0005ca56 -[UIApplication sendEvent:] + 38  
15  UIKit                           0x0005c500 _UIApplicationHandleEvent + 5016  
16  GraphicsServices                0x00004140 PurpleEventCallback + 660  
17  GraphicsServices                0x000041ca PurpleEventSignalCallback + 10  
18  CoreFoundation                  0x00071a86 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION_ + 6  
19  CoreFoundation                  0x000736ac _CFRunLoopDoSources0 + 188  
20  CoreFoundation                  0x00074504 _CFRunLoopRun + 224  
21  CoreFoundation                  0x0001d8e4 CFRunLoopRunSpecific + 224  
22  CoreFoundation                  0x0001d7ec CFRunLoopRunInMode + 52  
23  GraphicsServices                0x000036e8 GSEventRunModal + 108  
24  GraphicsServices                0x00003794 GSEventRun + 56  
25  UIKit                           0x000062a0 -[UIApplication _run] + 396  
26  UIKit                           0x00004e10 UIApplicationMain + 664  
27  TestRaspLayer                   0x00003034 main (main.m:14)  
28  TestRaspLayer                   0x00002fe8 start + 32  

Thread 1:  
0   libSystem.B.dylib               0x0002dc4c kevent + 24  
1   libSystem.B.dylib               0x000d6e44 _dispatch_mgr_invoke + 88  
2   libSystem.B.dylib               0x000d6894 _dispatch_queue_invoke + 96  
3   libSystem.B.dylib               0x000d6a34 _dispatch_worker_thread2 + 120  
4   libSystem.B.dylib               0x0007ad82 _pthread_wqthread + 258  
5   libSystem.B.dylib               0x00073fcc start_wqthread + 0  

Thread 2:  
0   libSystem.B.dylib               0x00001658 mach_msg_trap + 20  
1   libSystem.B.dylib               0x00003724 mach_msg + 44  
2   CoreFoundation                  0x000722c8 _CFRunLoopServiceMachPort + 88  
3   CoreFoundation                  0x00074582 _CFRunLoopRun + 350  
4   CoreFoundation                  0x0001d8e4 CFRunLoopRunSpecific + 224  
5   CoreFoundation                  0x0001d7ec CFRunLoopRunInMode + 52  
6   WebCore                         0x00003056 RunWebThread(void*) + 362  
7   libSystem.B.dylib               0x0007a986 _pthread_start + 242  
8   libSystem.B.dylib               0x000700e4 thread_start + 0  

Thread 3 Crashed:  
0   libicucore.A.dylib              0x00001bd0 uhash_get + 24  
1   libicucore.A.dylib              0x00055b10 ures_hasNext + 720  
2   libicucore.A.dylib              0x00055d08 ures_hasNext + 1224  
3   libicucore.A.dylib              0x00055e64 ures_hasNext + 1572  
4   libicucore.A.dylib              0x00003a28 ures_openDirect + 80  
5   libicucore.A.dylib              0x000b4dee icu::TimeZone::getGMT() + 442  
6   libicucore.A.dylib              0x0000861a icu::TimeZone::createSystemTimeZone(icu::UnicodeString const&) + 22  
7   libicucore.A.dylib              0x0000cf90 icu::TimeZone::createTimeZone(icu::UnicodeString const&) + 4  
8   libicucore.A.dylib              0x000bc6f8 ucal_setAttribute + 96  
9   libicucore.A.dylib              0x0000d650 ucal_open + 32  
10  CoreFoundation                  0x000a7968 _CFCalendarCreateUCalendar + 160  
11  CoreFoundation                  0x00029cde CFCalendarCreateWithIdentifier + 362  
12  CoreFoundation                  0x0008d128 _CFLogCString + 472  
13  CoreFoundation                  0x00029b52 _CFLogvEx + 166  
14  CoreFoundation                  0x0003d63e CFLog + 26  
15  CoreFoundation                  0x00015184 _CFAutoreleasePoolPop + 52  
16  Foundation                      0x0000422a NSPopAutoreleasePool + 2  
17  Foundation                      0x0000de16 -[_NSOperationInternal start] + 910  
18  Foundation                      0x0000da78 -[NSOperation start] + 16  
19  Foundation                      0x0007e5b4 _startOperations_block_invoke_2 + 40  
20  libSystem.B.dylib               0x000d5c54 _dispatch_call_block_and_release + 12  
21  libSystem.B.dylib               0x000d6a34 _dispatch_worker_thread2 + 120  
22  libSystem.B.dylib               0x0007ad82 _pthread_wqthread + 258  
23  libSystem.B.dylib               0x00073fcc start_wqthread + 0  

Thread 4:  
0   libSystem.B.dylib               0x00001f8e memcpy + 718  
1   TestRaspLayer                   0x00007718 _inline_memcpy_chk (_string.h:58)  
2   TestRaspLayer                   0x00007678 -[SERIALPort processRxBuffer]   (SERIALPort.m:243)   
3   CoreFoundation                  0x0009f06c _invoking_ + 60  
4   CoreFoundation                  0x00032706 -[NSInvocation invoke] + 102  
5   Foundation                      0x0007eb50 -[NSInvocationOperation main] + 72  
6   Foundation                      0x0000dd14 -[_NSOperationInternal start] + 652  
7   Foundation                      0x0000da78 -[NSOperation start] + 16  
8   Foundation                      0x0007e5b4 _startOperations_block_invoke_2 + 40  
9   libSystem.B.dylib               0x000d5c54 _dispatch_call_block_and_release + 12  
10  libSystem.B.dylib               0x000d6a34 _dispatch_worker_thread2 + 120  
11  libSystem.B.dylib               0x0007ad82 _pthread_wqthread + 258  
12  libSystem.B.dylib               0x00073fcc start_wqthread + 0  

Thread 3 crashed with ARM Thread State:  
    r0: 0x00000000    r1: 0x0000007f      r2: 0x00000077      r3: 0x80000001  
    r4: 0x0013fc50    r5: 0x0038003c      r6: 0x0038012c      r7: 0x0037ff70  
    r8: 0x00000000    r9: 0xffffffff     r10: 0x0013fcb4     r11: 0x00000000  
    ip: 0x00000077    sp: 0x0037ff68      lr: 0x339fbe09      pc: 0x339b8bd0  
  cpsr: 0x50000030  

Answer 1

当设备断开连接或空闲时，您的应用程序会崩溃吗？还是仅在设备发送数据时才会发生崩溃？

Answer 2

我认为

Thread 4:  
0   libSystem.B.dylib               0x00001f8e memcpy + 718  
1   TestRaspLayer                   0x00007718 _inline_memcpy_chk (_string.h:58)  
2   TestRaspLayer                   0x00007678 -[SERIALPort processRxBuffer]   (SERIALPort.m:243)

应用程序崩溃的地方，问题可能来自 SERIALPort 类中的 processRXBuffer 方法。
仔细检查你的代码，你就会发现问题出在哪里。