objc_msgSend crash : how can I find where?

enabled nszombies Is there any additional information anyone can see in this debug log that I could use to find the problem?

(gdb) bt  
0  0x30b7eca4 in objc_msgSend ()  
1  0x36179302 in -[MKMapView annotationContainer:viewForAnnotation:] ()  
2  0x36178f94 in -[MKAnnotationContainerView _addViewForAnnotation:] ()  
3  0x361a2faa in -[MKAnnotationContainerView userLocationAnnotationWillShow] ()  
4  0x3619fcbe in -[MKMapView(UserPositioningInternal) _runPositioningChange] ()  
5  0x3619da8c in -[MKMapView(UserPositioningInternal) _startPositioningChange:] ()  
6  0x361a1050 in -[MKMapView(UserPositioningInternal) locationManagerUpdatedLocation:] ()  
7  0x365cff02 in -[NSObject(NSObject) performSelector:withObject:] ()  
8  0x3660d2f8 in -[NSArray makeObjectsPerformSelector:withObject:] ()  
9  0x36190808 in -[MKLocationManager _reportLocationStatus:] ()  
10 0x36191d72 in -[MKLocationManager _reportLocationSuccess] ()
11 0x361919cc in -[MKLocationManager locationManager:didUpdateToLocation:fromLocation:] ()  
12 0x33bfbc2c in -[CLLocationManager onClientEventLocation:] ()  
13开发者_如何转开发 0x33bfbf48 in -[CLLocationManager onClientEvent:supportInfo:] ()  
14 0x33bfdd04 in OnClientEventInternal ()  
15 0x33bf57a2 in CLClientInvokeCallback ()  
16 0x33bf7c46 in CLClientHandleDaemonDataLocation ()  
17 0x33bf7d9c in CLClientHandleDaemonData ()  
18 0x3663070c in __CFMessagePortPerform ()    
19 0x36639a96 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ ()  
20 0x3663b83e in __CFRunLoopDoSource1 ()  
21 0x3663c60c in __CFRunLoopRun ()  
22 0x365ccec2 in CFRunLoopRunSpecific ()  
23 0x365ccdca in CFRunLoopRunInMode ()  
24 0x313c141e in GSEventRunModal ()  
25 0x313c14ca in GSEventRun ()  
26 0x33390d68 in -[UIApplication _run] ()  
27 0x3338e806 in UIApplicationMain ()  
28 0x000039ca in main (argc=1, argv=0x2fdff55c) at main.m:14    
(gdb) 

UPDATE:

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation
{


 MKAnnotationView* annView = nil;

    if ( [annotation isKindOfClass: [AnnotationItem class]] )
    {
        MKPinAnnotationView* pin = (MKPinAnnotationView*)[mapView dequeueReusableAnnotationViewWithIdentifier: kListingAnnotationIdentifier];

        if ( nil == pin )
        {
            pin = [[[MKPinAnnotationView alloc] initWithAnnotation: annotation reuseIdentifier: kListingAnnotationIdentifier] autorelease];
        }
        else
        {
            [pin setAnnotation: annotation];
        }

        pin.canShowCallout = YES;

        pin.pinColor = MKPinAnnotationColorGreen;


        UIImage* img = [UIImage imageNamed: @"logap.png"] ;
        pin.leftCalloutAccessoryView = [[[UIImageView alloc] initWithImage: img] autorelease];


        pin.rightCalloutAccessoryView = [UIButton buttonWithType: UIButtonTypeDetailDisclosure];

        annView = pin;

    }
    return annView;



}

Your debug log shows a crash when the mapView is trying to display (a change in) the user's location. User location is an annotation of class MKUserLocation, and if that annotation gets passed to your implementation of mapView:viewForAnnotation, your code returns a pointer to nil (that is, it returns an MKAnnotationView object named annView, whose value is set to nil).

So I suspect you're crashing when the user's location appears or moves on screen, or that the difference between nil and "an MKAnnotationView object whose value is set to nil" may suddenly matter to Cocoa at hard-to-reproduce times. Try testing for whether the annotation is of class MKUserLocation, and explicitly returning nil in this case.