我们的 iPad 应用程序“MyApp”从现场收到了多份无法重现的崩溃报告，每天约有 3000 名用户。原因：“无法识别的选择器发送到实例” 受影响的设备：仅 iPad 1。
崩溃报告是指[__NSCFDictionary buttonPressed:]whilebuttonPressed:是 UIButton 的操作。显然，在崩溃情况下，按钮还没有准备好接收消息。相反，消息被分派到内存中的某个其他实例（在大多数情况下是字典）。
该操作buttonPressed:通过一个 xib 文件附加到按钮上（还有一种情况，即该操作以编程方式附加到图像视图）。buttonPressed:是当应用程序被带到前面时用户可能首先触发的操作。我怀疑在这些情况下，应用程序没有完全初始化（回到前面）并且无法恢复。
我的怀疑是基于符号（总是与这些崩溃一起发生）：（_resourceLoadLoop在主线程中执行？）和_dispatch_mgr_wakeup.
你有什么意见？您是否与 iPad 1 客户有过类似的经历？有已知的错误吗？
以下是典型崩溃堆栈的内容：
Hardware Model: iPad1,1
Code Type: ARM
Parent Process: launchd [1]
Date/Time: 2012-12-04 06:35:48 +0000
OS Version: iPhone OS 5.1.1 (9B206)
Report Version: 104
Exception Type: SIGABRT
Exception Codes: #0 at 0x35a2f32c
Crashed Thread: 0
Application Specific Information:
*** Terminating app due to uncaught exception \'NSInvalidArgumentException\', reason: \'-[__NSCFDictionary buttonPressed:]: unrecognized selector sent to instance 0x40eaa0\'
Last Exception Backtrace:
0 CoreFoundation 0x359b988f __exceptionPreprocess + 163
1 libobjc.A.dylib 0x335dd259 objc_exception_throw + 33
2 CoreFoundation 0x359bca9b -[NSObject doesNotRecognizeSelector:] + 175
3 CoreFoundation 0x359bb915 ___forwarding___ + 301
4 CoreFoundation 0x35916650 _CF_forwarding_prep_0 + 48
5 CoreFoundation 0x359133fd -[NSObject performSelector:withObject:withObject:] + 53
6 UIKit 0x330d4e07 -[UIApplication sendAction:to:from:forEvent:] + 63
7 UIKit 0x330d4dc3 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 31
8 UIKit 0x330d4da1 -[UIControl sendAction:to:forEvent:] + 45
9 UIKit 0x330d4b11 -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 493
10 UIKit 0x330d5449 -[UIControl touchesEnded:withEvent:] + 477
11 UIKit 0x330d392b -[UIWindow _sendTouchesForEvent:] + 319
12 UIKit 0x330d3319 -[UIWindow sendEvent:] + 381
13 UIKit 0x330b9695 -[UIApplication sendEvent:] + 357
14 UIKit 0x330b8f3b _UIApplicationHandleEvent + 5827
15 GraphicsServices 0x336ab22b PurpleEventCallback + 883
16 CoreFoundation 0x3598d523 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 39
17 CoreFoundation 0x3598d4c5 __CFRunLoopDoSource1 + 141
18 CoreFoundation 0x3598c313 __CFRunLoopRun + 1371
19 CoreFoundation 0x3590f4a5 CFRunLoopRunSpecific + 301
20 CoreFoundation 0x3590f36d CFRunLoopRunInMode + 105
21 GraphicsServices 0x336aa439 GSEventRunModal + 137
22 UIKit 0x330e7cd5 UIApplicationMain + 1081
23 MyApp 0x0002411b main (main.m:14)
24 MyApp 0x000240c0 start + 40
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x35a2f32c __pthread_kill + 8
1 libsystem_c.dylib 0x34c1029f abort + 95
2 MyApp 0x0012d595 +[PLCrashReporter sharedReporter] + 1
3 CoreFoundation 0x359b9957 __handleUncaughtException + 75
4 libobjc.A.dylib 0x335dd345 _objc_terminate + 129
5 libc++abi.dylib 0x352253c5 safe_handler_caller(void (*)()) + 77
6 libc++abi.dylib 0x35225451 operator delete(void*) + 1
7 libc++abi.dylib 0x35226825 __cxa_current_exception_type + 1
8 libobjc.A.dylib 0x335dd2a9 objc_exception_rethrow + 13
9 CoreFoundation 0x3590f50d CFRunLoopRunSpecific + 405
10 CoreFoundation 0x3590f36d CFRunLoopRunInMode + 105
11 GraphicsServices 0x336aa439 GSEventRunModal + 137
12 UIKit 0x330e7cd5 UIApplicationMain + 1081
13 MyApp 0x0002411b main (main.m:14)
Thread 1:
0 libsystem_kernel.dylib 0x35a1f3a8 kevent + 24
1 libdispatch.dylib 0x33d52bc9 _dispatch_mgr_wakeup + 1
Thread 2:
0 libsystem_kernel.dylib 0x35a1f004 mach_msg_trap + 20
1 CoreFoundation 0x3598d3f3 __CFRunLoopServiceMachPort + 127
2 CoreFoundation 0x3598c12b __CFRunLoopRun + 883
3 CoreFoundation 0x3590f4a5 CFRunLoopRunSpecific + 301
4 CoreFoundation 0x3590f36d CFRunLoopRunInMode + 105
5 WebCore 0x37655ca3 RunWebThread(void*) + 403
6 libsystem_c.dylib 0x34bd8735 _pthread_start + 321
Thread 3:
0 libsystem_kernel.dylib 0x35a1f004 mach_msg_trap + 20
1 CoreFoundation 0x3598d3f3 __CFRunLoopServiceMachPort + 127
2 CoreFoundation 0x3598c12b __CFRunLoopRun + 883
3 CoreFoundation 0x3590f4a5 CFRunLoopRunSpecific + 301
4 CoreFoundation 0x3590f36d CFRunLoopRunInMode + 105
5 Foundation 0x34d54bb9 +[NSURLConnection(Loader) _resourceLoadLoop:] + 309
6 Foundation 0x34d54a81 -[NSThread main] + 73
7 Foundation 0x34de8591 __NSThread__main__ + 1049
8 libsystem_c.dylib 0x34bd8735 _pthread_start + 321
Thread 4:
0 libsystem_kernel.dylib 0x35a2f570 __select + 20
1 libsystem_c.dylib 0x34bd8735 _pthread_start + 321
Thread 5:
0 libsystem_kernel.dylib 0x35a2fcd4 __workq_kernreturn + 8
Thread 6:
0 libsystem_kernel.dylib 0x35a2fcd4 __workq_kernreturn + 8
Thread 0 crashed with ARM Thread State:
r0: 0x00000000 r1: 0x00000000 r2: 0x00000001 r3: 0x00000000
r4: 0x00000006 r5: 0x3f2dbd98 r6: 0x00000002 r7: 0x2fe20a38
r8: 0x00469e00 r9: 0x00000000 r10: 0x00000000 r11: 0x0040eaa0
ip: 0x00000148 sp: 0x2fe20a2c lr: 0x34c1720f pc: 0x35a2f32c
cpsr: 0x00080010
Binary Images:
0x22000 - 0x288fff +MyApp armv7 <1f677ffc81aa3ccf958c65a92cce8418> /var/mobile/Applications/1D49C89A-36EA-43FC-BE76-7B770E36491B/MyApp.app/MyApp
0x3049d000 - 0x30550fff iTunesStore armv7 <b3c0cce5f8e632e18f841c32b68f57a1> /System/Library/PrivateFrameworks/iTunesStore.framework/iTunesStore
0x30555000 - 0x305d8fff MapKit armv7 <e39706ac199134a497954e1f1d6d7245> /System/Library/Frameworks/MapKit.framework/MapKit
0x305d9000 - 0x305dffff liblaunch.dylib armv7 <aa2bcba6fc7a36a191958fef2e995475> /usr/lib/system/liblaunch.dylib
0x306dd000 - 0x306f1fff PersistentConnection armv7 <54091a638f8731cd85ccf00fa06972c3> /System/Library/PrivateFrameworks/PersistentConnection.framework/PersistentConnection
0x30745000 - 0x30824fff RawCamera armv7 <293f818ba6533dceae8b900b6ed3c887> /System/Library/CoreServices/RawCamera.bundle/RawCamera
0x30825000 - 0x30882fff StoreServices armv7 <6ce256d3cf433e4aa1af8d696bf1f75d> /System/Library/PrivateFrameworks/StoreServices.framework/StoreServices
0x30883000 - 0x308cffff CoreTelephony armv7 <b8f80d5d594c31d2b5d8fba9fdedb7e1> /System/Library/Frameworks/CoreTelephony.framework/CoreTelephony
0x308f1000 - 0x30929fff VideoToolbox armv7 <9f25f38d1cd13a1daff99cfde8884410> /System/Library/PrivateFrameworks/VideoToolbox.framework/VideoToolbox
0x3092a000 - 0x30956fff libtidy.A.dylib armv7 <3aacc5b650e037c086a8ff6657d154bf> /usr/lib/libtidy.A.dylib
0x30ef1000 - 0x30f42fff CoreText armv7 <5bfac4ee88d03d5b87a1f105abb7756c> /System/Library/Frameworks/CoreText.framework/CoreText
0x30f43000 - 0x30f47fff CertUI armv7 <f503892ef60e36108d28d8f9d6144d2a> /System/Library/PrivateFrameworks/CertUI.framework/CertUI
0x30fb3000 - 0x30fb3fff liblangid.dylib armv7 <644ff4bcfbf337b5b5859e3f0fc0a9a8> /usr/lib/liblangid.dylib
0x30fb4000 - 0x30fcafff EAP8021X armv7 <952fcfdec0633aff923768fca1a26fcb> /System/Library/PrivateFrameworks/EAP8021X.framework/EAP8021X
0x30fcb000 - 0x30fe0fff libresolv.9.dylib armv7 <66f7557fa4b43979b186e00271839fdb> /usr/lib/libresolv.9.dylib
0x3129d000 - 0x312bafff libsystem_info.dylib armv7 <50863bcbf478323e96a8e5b1a83ea6f9> /usr/lib/system/libsystem_info.dylib
0x312c0000 - 0x31433fff MediaPlayer armv7 <63cdf8f9c66d36e7a4e69e2f6cae854f> /System/Library/Frameworks/MediaPlayer.framework/MediaPlayer
0x315ea000 - 0x315eafff vecLib armv7 <a2cfe25e77aa36bfb4a30b2d0d2dd465>
[...]