AVAudio, random crashes - avaudioplayer

Question

Here is a strange issue I am having with sound in an iOS app.
Since my code works about 90% of the time, it is not that easy to reproduce the bug.
But the problem seems to happen (once in a while) at the end of a recording; either when I stop the recording manually or when it stops automatically.
Under the debugger I see the crash showing up at a point in the program related to the plugging in/out of an earphone.
In reality there is no earphone plugged in and I am not plugging in or out any earphone at all.
I have this code at some point in my program:
AudioSessionPropertyID routeChangeID=kAudioSessionProperty_AudioRouteChange;
AudioSessionAddPropertyListener(routeChangeID,svcHandleRouteChange,(__bridge void *)(self));
and this:
void svcHandleRouteChange(void *inUserData,AudioSessionPropertyID inPropertyID,
UInt32 inPropertyValueSize,const void *inPropertyValue)
{
CFStringRef route;
UInt32 propertySize=sizeof(CFStringRef);
if (AudioSessionGetProperty(kAudioSessionProperty_AudioRoute,&propertySize,&route)==0) {
NSString *routeString = (__bridge NSString *) route;
if ([routeString isEqualToString: #"Headphone"]) {
// A headphone is now plugged in.
// We do nothing.
} else if ([routeString isEqualToString: #"Speaker"]) {
// No headphone is plugged in. The device is using the speaker.
LocalViewController* this=(__bridge LocalViewController*)inUserData;
//[this->audioPlayer pause]; // The private variable audioPlayer could be accessed like this.
[this headPhoneOut];
} else {
// This should not happen!!
}
}
}
The crash is happening in the line:
LocalViewController* this=(__bridge LocalViewController*)inUserData;
And finally here is the backtrace I get in the debugger after the crash in case that may help someone to give me a hint:
(lldb) bt
* thread #5: tid = 0x292d8, 0x3abba0ec libobjc.A.dylib`objc_retain + 12, stop reason = EXC_BAD_ACCESS (code=1, address=0x6e966a29)
frame #0: 0x3abba0ec libobjc.A.dylib`objc_retain + 12
frame #1: 0x000eb7d6 parl100`svcHandleRouteChange(inUserData=0x14e5f190, inPropertyID=1919902568, inPropertyValueSize=4, inPropertyValue=0x14f0b120) + 182 at LocalViewController.m:801
frame #2: 0x301ae944 AudioToolbox`AudioSessionPropertyListeners::CallPropertyListenersImp(unsigned long, unsigned long, void const*) + 684
frame #3: 0x301ae456 AudioToolbox`AudioSessionPropertyListeners::CallPropertyListeners(unsigned long, unsigned long, void const*) + 334
frame #4: 0x301aee90 AudioToolbox`HandleCFPropertyListChange(unsigned int, unsigned long, unsigned char*, unsigned int) + 412
frame #5: 0x301aec7e AudioToolbox`HandleAudioSessionPropertyChangedBlobListenerMessage(unsigned int, void*, unsigned int) + 206
frame #6: 0x301aeb0e AudioToolbox`ASCallbackReceiver_AudioSessionPropertyChangedBlobListenerMessage + 178
frame #7: 0x301aea3e AudioToolbox`_XAudioSessionPropertyChangedBlobListenerMessage + 94
frame #8: 0x301ae088 AudioToolbox`mshMIGPerform + 124
frame #9: 0x308dc9e6 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 34
frame #10: 0x308dc982 CoreFoundation`__CFRunLoopDoSource1 + 346
frame #11: 0x308db156 CoreFoundation`__CFRunLoopRun + 1398
frame #12: 0x30845ce6 CoreFoundation`CFRunLoopRunSpecific + 522
frame #13: 0x30845aca CoreFoundation`CFRunLoopRunInMode + 106
frame #14: 0x2f837588 libAVFAudio.dylib`GenericRunLoopThread::Entry(void*) + 128
frame #15: 0x2f82ba96 libAVFAudio.dylib`CAPThread::Entry(CAPThread*) + 178
frame #16: 0x3b1e4c1c libsystem_pthread.dylib`_pthread_body + 140
frame #17: 0x3b1e4b8e libsystem_pthread.dylib`_pthread_start + 102
(lldb)
Here is a second case where the same problem happens at a different point in the app:
2013-10-23 12:25:12.135 parl100[1532:60b] audioRecorderDidFinishRecording
(lldb) bt
* thread #5: tid = 0x2b37a, 0x3abba0ec libobjc.A.dylib`objc_retain + 12, stop reason = EXC_BAD_ACCESS (code=1, address=0xd0003511)
frame #0: 0x3abba0ec libobjc.A.dylib`objc_retain + 12
frame #1: 0x000f18a2 parl100`cvcHandleRouteChange(inUserData=0x176b5610, inPropertyID=1919902568, inPropertyValueSize=4, inPropertyValue=0x1762d660) + 182 at ZapViewController.m:566
frame #2: 0x301ae944 AudioToolbox`AudioSessionPropertyListeners::CallPropertyListenersImp(unsigned long, unsigned long, void const*) + 684
frame #3: 0x301ae456 AudioToolbox`AudioSessionPropertyListeners::CallPropertyListeners(unsigned long, unsigned long, void const*) + 334
frame #4: 0x301aee90 AudioToolbox`HandleCFPropertyListChange(unsigned int, unsigned long, unsigned char*, unsigned int) + 412
frame #5: 0x301aec7e AudioToolbox`HandleAudioSessionPropertyChangedBlobListenerMessage(unsigned int, void*, unsigned int) + 206
frame #6: 0x301aeb0e AudioToolbox`ASCallbackReceiver_AudioSessionPropertyChangedBlobListenerMessage + 178
frame #7: 0x301aea3e AudioToolbox`_XAudioSessionPropertyChangedBlobListenerMessage + 94
frame #8: 0x301ae088 AudioToolbox`mshMIGPerform + 124
frame #9: 0x308dc9e6 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 34
frame #10: 0x308dc982 CoreFoundation`__CFRunLoopDoSource1 + 346
frame #11: 0x308db156 CoreFoundation`__CFRunLoopRun + 1398
frame #12: 0x30845ce6 CoreFoundation`CFRunLoopRunSpecific + 522
frame #13: 0x30845aca CoreFoundation`CFRunLoopRunInMode + 106
frame #14: 0x2f837588 libAVFAudio.dylib`GenericRunLoopThread::Entry(void*) + 128
frame #15: 0x2f82ba96 libAVFAudio.dylib`CAPThread::Entry(CAPThread*) + 178
frame #16: 0x3b1e4c1c libsystem_pthread.dylib`_pthread_body + 140
frame #17: 0x3b1e4b8e libsystem_pthread.dylib`_pthread_start + 102
(lldb)
I can provide more code if necessary. Just tell me what I should include.
I hope someone can point me to something I must not be doing the proper way.