SIGSEGV crash in iOS devices from which I cannot work out the cause

There are many threads around about crash reports in iOS and how to debug crashes but I thought I'd also post mine here as I haven't read a post that helps specifically to my case. I released my app to the AppStore a week or so ago and I have heard from a small number of people that their app is crashing. I cannot personally replicate the crashes (nor can they) on their app - although it appears to be when the user returns to the game after having not played it for a while (they cannot confirm whether they quit the app via double-clicking the home button or not, though).

So in my attempts to solve this I ran the game on my phone as well as the simulator, and I cannot replicate this at all - which makes the problem all the harder to work out. I thought I would post the pertinent parts of the crash report and see if anyone can make sense of it!

Incident Identifier: 52C3B61C-D05A-4F2D-91A0-0192A668FCBC   
Hardware Model:      iPhone2,1  
Process:         Transfer Quiz [2474]    
Path:            /var/mobile/Applications/6BC39FBB-59F3-45A7-BD94-449914CFFFA8/Transfer      Quiz.app/Transfer Quiz 
Identifier:      Transfer Quiz  
Version:         ??? (???)  
Code Type:       ARM (Native)   
Parent Process:  launchd [1]    

Date/Time:       2012-08-29 16:49:03.080 +0100  
OS Version:      iPhone OS 5.1.1 (9B206)    
Report Version:  104    

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)   
Exception Codes: KERN_INVALID_ADDRESS at 0xc01236f2 
Crashed Thread:  0  

Thread 0 name:  Dispatch queue: com.apple.main-thread   
Thread 0 Crashed:   
0   libobjc.A.dylib                 0x374faf7e objc_msgSend + 22
1   Transfer Quiz                   0x000023c4 0x000013c4
2   Transfer Quiz                   0x0000230c 0x0000130c
3   libdispatch.dylib               0x359dac52 _dispatch_call_block_and_release
4   libdispatch.dylib               0x359e5e8a _dispatch_main_queue_callback_4CF$VARIANT$up
5   CoreFoundation                  0x311952a6 __CFRunLoopRun + 1262
6   CoreFoundation                  0x3111849e CFRunLoopRunSpecific
7   CoreFoundation                  0x31118366 CFRunLoopRunInMode
8   GraphicsServices                0x33192432 GSEventRunModal
9   UIKit                           0x3087bcce UIApplicationMain
10  Transfer Quiz                   0x000030d4 0x000020d4
11  Transfer Quiz                   0x000021a8 0x000011a8

I am using ARC in my project, and the problem appears to be more pertinent to older devices (3GS) as opposed to newer models, which makes things more interesting.

If anyone has any suggestions, I would love to hear them.

PS - I enabled NSZombies in Xcode too, without any luck in finding anything (probably as I cannot replicate the crash!) - I couldn't find any memory leaks, either.

Thanks,

Andy.

This might be related to your app getting cleared from memory while another app is running. This would also explain why it happens more often on older devices.

Put a log message into your didReceiveMemoryWarning delegate methods, they will probably appear in your crash log as one of the last lines.