Crash Report - iOS - View Controller Related? - ios

Question

Can anyone help me understand a crash report? This is the first time I have ever had to deal with one since iOS App developing in 8 months.
I know it is something to do with dismissing a view controller that is causing it, but I have made no changes to the code regarding this but all of a sudden it is starting to cause problems. Any guidance on where to start would be amazing.
Date/Time: 2013-03-10 14:56:06.091 +0000
OS Version: iOS 6.1.2 (10B146)
Report Version: 104
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x00000000
Crashed Thread: 0
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libobjc.A.dylib 0x3afee5b6 objc_msgSend + 22
1 AVFoundation 0x3247f752 -[AVAudioPlayer(AVAudioPlayerPriv) finishedPlaying:] + 74
2 Foundation 0x33c700f0 __NSThreadPerformPerform + 456
3 CoreFoundation 0x3332e680 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 12
4 CoreFoundation 0x3332dee4 __CFRunLoopDoSources0 + 208
5 CoreFoundation 0x3332ccb2 __CFRunLoopRun + 642
6 CoreFoundation 0x3329feb8 CFRunLoopRunSpecific + 352
7 CoreFoundation 0x3329fd44 CFRunLoopRunInMode + 100
8 GraphicsServices 0x36e612e6 GSEventRunModal + 70
9 UIKit 0x351b52fc UIApplicationMain + 1116
10 iWhovian 0x000391fe main (main.m:15)
11 iWhovian 0x0002f56c start + 36
Thread 1 name: Dispatch queue: com.apple.libdispatch-manager
Thread 1:
0 libsystem_kernel.dylib 0x3b4e1648 kevent64 + 24
1 libdispatch.dylib 0x3b41a4ec _dispatch_mgr_invoke + 792
2 libdispatch.dylib 0x3b40cdf4 _dispatch_mgr_thread$VARIANT$up + 32
Thread 2 name: WebThread
Thread 2:
0 libsystem_kernel.dylib 0x3b4e0eb4 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x3b4e1048 mach_msg + 36
2 CoreFoundation 0x3332e040 __CFRunLoopServiceMachPort + 124
3 CoreFoundation 0x3332cd9e __CFRunLoopRun + 878
4 CoreFoundation 0x3329feb8 CFRunLoopRunSpecific + 352
5 CoreFoundation 0x3329fd44 CFRunLoopRunInMode + 100
6 WebCore 0x39294500 RunWebThread(void*) + 440
7 libsystem_c.dylib 0x3b44a30e _pthread_start + 306
8 libsystem_c.dylib 0x3b44a1d4 thread_start + 4
Thread 3:
0 libsystem_kernel.dylib 0x3b4f108c __psynch_cvwait + 24
1 libsystem_c.dylib 0x3b442d2a _pthread_cond_wait + 642
2 libsystem_c.dylib 0x3b44cf14 pthread_cond_wait + 36
3 Foundation 0x33bec4d2 -[NSCondition wait] + 190
4 iWhovian 0x0006ef90 -[PFCommandCache runLoop] (PFCommandCache.m:491)
5 Foundation 0x33c6fe80 __NSThread__main__ + 968
6 libsystem_c.dylib 0x3b44a30e _pthread_start + 306
7 libsystem_c.dylib 0x3b44a1d4 thread_start + 4
Thread 4 name: AQClient
Thread 4:
0 libsystem_kernel.dylib 0x3b4e0eb4 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x3b4e1048 mach_msg + 36
2 CoreFoundation 0x3332e040 __CFRunLoopServiceMachPort + 124
3 CoreFoundation 0x3332cd9e __CFRunLoopRun + 878
4 CoreFoundation 0x3329feb8 CFRunLoopRunSpecific + 352
5 CoreFoundation 0x3329fd44 CFRunLoopRunInMode + 100
6 AudioToolbox 0x32d816fe GenericRunLoopThread::Entry(void*) + 134
7 AudioToolbox 0x32d62882 CAPThread::Entry(CAPThread*) + 294
8 libsystem_c.dylib 0x3b44a30e _pthread_start + 306
9 libsystem_c.dylib 0x3b44a1d4 thread_start + 4
Thread 5:
0 libsystem_kernel.dylib 0x3b4f1d98 __workq_kernreturn + 8
1 libsystem_c.dylib 0x3b43fcf6 _pthread_workq_return + 14
2 libsystem_c.dylib 0x3b43fa12 _pthread_wqthread + 362
3 libsystem_c.dylib 0x3b43f8a0 start_wqthread + 4
Thread 6 name: Dispatch queue: com.apple.NSXPCConnection.m-user.com.apple.gamed
Thread 6:
0 libobjc.A.dylib 0x3afee5b0 objc_msgSend + 16
1 CoreFoundation 0x332b0fdc -[__NSSetI member:] + 140
2 CoreFoundation 0x332b0f44 -[NSSet containsObject:] + 28
3 Foundation 0x33c08978 -[NSCoder _validateAllowedClass:forKey:allowingInvocations:] + 124
4 Foundation 0x33c08402 _decodeObjectStuff + 282
5 Foundation 0x33c08200 -[NSXPCDecoder decodeObjectOfClasses:forKey:] + 76
6 GameKit 0x33e2f8fa -[GKInternalRepresentation initWithCoder:] + 238
7 Foundation 0x33c086f2 _decodeObjectStuff + 1034
8 Foundation 0x33d1fda8 -[NSXPCDecoder _decodeArrayOfObjectsForKey:] + 532
9 Foundation 0x33bf4ebc -[NSArray(NSArray) initWithCoder:] + 784
10 Foundation 0x33c086f2 _decodeObjectStuff + 1034
11 Foundation 0x33c08200 -[NSXPCDecoder decodeObjectOfClasses:forKey:] + 76
12 GameKit 0x33e2f8fa -[GKInternalRepresentation initWithCoder:] + 238
13 Foundation 0x33c086f2 _decodeObjectStuff + 1034
14 Foundation 0x33c08200 -[NSXPCDecoder decodeObjectOfClasses:forKey:] + 76
15 Foundation 0x33c09fe8 _walkAndDecodeData + 1708
16 Foundation 0x33c0988c decodeInvocationArguments + 1368
17 Foundation 0x33c08fc8 -[NSXPCDecoder decodeInvocation] + 860
18 Foundation 0x33c08630 _decodeObjectStuff + 840
19 Foundation 0x33c08200 -[NSXPCDecoder decodeObjectOfClasses:forKey:] + 76
20 Foundation 0x33c07c04 -[NSXPCConnection _decodeAndInvokeReplyBlockWithData:] + 548
21 Foundation 0x33d1eedc __message_handler_block_invoke_0 + 32
22 libdispatch.dylib 0x3b40b11c _dispatch_call_block_and_release + 8
23 libdispatch.dylib 0x3b40a996 _dispatch_queue_drain$VARIANT$up + 142
24 libdispatch.dylib 0x3b40a890 _dispatch_queue_invoke$VARIANT$up + 32
25 libdispatch.dylib 0x3b419212 _dispatch_root_queue_drain + 190
26 libdispatch.dylib 0x3b4193b4 _dispatch_worker_thread2 + 80
27 libsystem_c.dylib 0x3b43fa0e _pthread_wqthread + 358
28 libsystem_c.dylib 0x3b43f8a0 start_wqthread + 4
Thread 7:
0 libsystem_kernel.dylib 0x3b4f1d98 __workq_kernreturn + 8
1 libsystem_c.dylib 0x3b43fcf6 _pthread_workq_return + 14
2 libsystem_c.dylib 0x3b43fa12 _pthread_wqthread + 362
3 libsystem_c.dylib 0x3b43f8a0 start_wqthread + 4
Thread 0 crashed with ARM Thread State (32-bit):
r0: 0x208a4ef0 r1: 0x38e042ae r2: 0x33f0ac6c r3: 0x00000008
r4: 0x20747372 r5: 0x2089ac70 r6: 0x33f0ac6c r7: 0x2fdd2df8
r8: 0x3b667530 r9: 0x0e3810ab r10: 0x00000000 r11: 0x1fd4dd90
ip: 0x3b5734ac sp: 0x2fdd2de0 lr: 0x3247f757 pc: 0x3afee5b6
cpsr: 0x20070030

Answer 1

I ran into this one a while ago. The problem can be fixed by setting the AVAudioPlayer instance's delegate to nil in your view controller's dealloc method. Unless you do this, the audio player tries to make one last call to its delegate to let it know that is is done playing. But if the delegate has been deallocated, you get this crash.
- (void)dealloc {
_myPlayer.delegate = nil; // _myPlayer is your AVAudioPlayer instance
[super dealloc]; // Only is you are not using ARC
}

Answer 2

You're most likely trying to access an object, that hast been deallocated. Have a look at
Debugging EXC_BAD_ACCESS Error in Xcode using Instruments (Archived)
to see how you can track it down.