How to track down strange crashes of iPad app in AQClient thread?
Date/Time:       2011-11-08 19:07:21.044 +0100
OS Version:      iPhone OS 5.0 (9A334)
Report Version:  104

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x406cad3d
Crashed Thread:  9

Thread 9 name:  AQClient
Thread 9 Crashed:
0   libobjc.A.dylib                 0x30107fbc objc_msgSend + 16
1   AVFoundation                    0x3420cdc8 _ZL27AudioPlayerAQOutputCallbackPvP16OpaqueAudioQueueP16AudioQueueBuffer + 28
2   AudioToolbox                    0x32a409fe ClientMessageHandler::OutputBufferComplete(unsigned int) + 98
3   AudioToolbox                    0x32a425d6 AQClientCallbackMessageReader::DispatchCallbacks(unsigned char*, unsigned int, void*, unsigned int) + 198
4   AudioToolbox                    0x32a408dc AQCallbackReceiver_CallbackNotificationsAvailable + 364
5   AudioToolbox                    0x329ee4b6 _XCallbackNotificationsAvailable + 54
6   AudioToolbox                    0x329e436c mshMIGPerform + 368
7   CoreFoundation                  0x34fa454c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 32
8   CoreFoundation                  0x34fa44ee __CFRunLoopDoSource1 + 134
9   CoreFoundation                  0x34fa333c __CFRunLoopRun + 1364
10  CoreFoundation                  0x34f264d6 CFRunLoopRunSpecific + 294
11  CoreFoundation                  0x34f2639e CFRunLoopRunInMode + 98
12  AudioToolbox                    0x32a3d29c GenericRunLoopThread::Entry(void*) + 116
13  AudioToolbox                    0x329c5aac CAPThread::Entry(CAPThread*) + 208
14  libsystem_c.dylib               0x35756c16 _pthread_start + 314
15  libsystem_c.dylib               0x35756ad0 thread_start + 0

Nov  8 19:17:19 unknown XXX[1753] <Warning>: Finished movie
Nov  8 19:17:19 unknown XXX[1753] <Warning>: Finished movie
Nov  8 19:17:20 unknown XXX[1753] <Warning>: flipping
Nov  8 19:17:20 unknown XXX[1753] <Warning>: flipping
Nov  8 19:17:20 unknown XXX[1753] <Warning>: --> dealloc <AVAudioPlayer: 0x6887530> (d2_s3_l3_q9.aif)
Nov  8 19:17:20 unknown XXX[1753] <Warning>: --> dealloc <AVAudioPlayer: 0x6887530> (d2_s3_l3_q9.aif)
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x68859f0 of class __NSCFString autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x11ef30 of class __NSCFString autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x1a6720 of class __NSCFString autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x6872400 of class __NSCFString autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug

(...)

Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x6872ed0 of class __NSCFDictionary autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x10cf80 of class __NSCFNumber autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x6850480 of class __NSCFString autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x10a530 of class __NSCFNumber autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x1d15d0 of class __NSCFNumber autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x6884550 of class TFCrashHandler autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x685ec10 of class __NSCFString autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:20 unknown UIKitApplication:com.bundle.name[0x2432][1753] <Notice>: objc[1753]: Object 0x6856270 of class __NSCFDictionary autoreleased with no pool in place - just leaking - break on objc_autoreleaseNoPool() to debug
Nov  8 19:17:21 unknown com.apple.networkd[1763] <Notice>: main:212 networkd.1763 built Sep 16 2011 00:02:59
Nov  8 19:17:25 unknown ReportCrash[1764] <Notice>: Formulating crash report for process XXX[1753]
Nov  8 19:17:25 unknown com.apple.launchd[1] <Warning>: (UIKitApplication:com.bundle.name[0x2432]) Job appears to have crashed: Segmentation fault: 11
Nov  8 19:17:25 unknown SpringBoard[15] <Warning>: Application 'XXX' exited abnormally with signal 11: Segmentation fault: 11
Nov  8 19:17:25 unknown ReportCrash[1764] <Error>: Saved crashreport to /var/mobile/Library/Logs/CrashReporter/XXX_2011-11-08-191724_iKotapad.plist using uid: 0 gid: 0, synthetic_euid: 501 egid: 0

@autoreleasepool {
    NSData *data = [NSData dataWithBytes:myBytes length:myLength];
    //do something with data
}