Can not reproduce a crash found by the app review. Can anyone help make sense of this crash report? - iphone

Question

Apple rejected our iphone app, showing that it crashed on iPad. We could not reproduce the crash on 3 different iPads and asked them to confirm. Apple came back saying that they produced the crash on iPhone 4 (although the log shows iPhone 3). We can not reproduce it...
They produce the crash by: Launch app. Select Let me look around
first. App crashes.
The log they sent us back seems to not show any of the apps own methods called:
ncident Identifier: 8B5E90DE-99FD-4279-B634-2C777209F2B3
CrashReporter Key: 6e9ccd0fcdc29915ebe22fb7376bd343cdcc252a
Hardware Model: iPhone3,1
Process: Snug [297]
Path: /var/mobile/Applications/DB3EFF00-7E5E-492A-9108-1341B6371B0D/Snug.app/Snug
Identifier: Snug
Version: ??? (???)
Code Type: ARM (Native)
Parent Process: launchd [1]
Date/Time: 2012-09-09 13:00:32.642 -0700
OS Version: iPhone OS 5.1.1 (9B206)
Report Version: 104
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x00000000, 0x00000000
Crashed Thread: 6
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0:
0 libsystem_kernel.dylib 0x319e7660 __semwait_signal_nocancel + 24
1 libsystem_c.dylib 0x3410b4da nanosleep$NOCANCEL + 118
2 libsystem_c.dylib 0x340dd3a0 usleep$NOCANCEL + 44
3 libsystem_c.dylib 0x340dd2b6 abort + 118
4 Snug 0x001f8760 uncaught_exception_handler + 12
5 CoreFoundation 0x37830950 __handleUncaughtException + 68
6 libobjc.A.dylib 0x3553533e _objc_terminate + 122
7 libc++abi.dylib 0x36f683be safe_handler_caller(void (*)()) + 70
8 libc++abi.dylib 0x36f6844a std::terminate() + 14
9 libc++abi.dylib 0x36f6981e __cxa_rethrow + 82
10 libobjc.A.dylib 0x355352a2 objc_exception_rethrow + 6
11 CoreFoundation 0x37786506 CFRunLoopRunSpecific + 398
12 CoreFoundation 0x37786366 CFRunLoopRunInMode + 98
13 GraphicsServices 0x33f45432 GSEventRunModal + 130
14 UIKit 0x31532cce UIApplicationMain + 1074
15 Snug 0x000f590c main (main.m:16)
16 Snug 0x000f58c0 start + 32
Thread 1 name: Dispatch queue: com.apple.libdispatch-manager
Thread 1:
0 libsystem_kernel.dylib 0x319d73a8 kevent + 24
1 libdispatch.dylib 0x3095cea4 _dispatch_mgr_invoke + 708
2 libdispatch.dylib 0x3095cbc2 _dispatch_mgr_thread + 30
Thread 2:
0 libsystem_kernel.dylib 0x319e7cd4 __workq_kernreturn + 8
1 libsystem_c.dylib 0x3409ff36 _pthread_wqthread + 610
2 libsystem_c.dylib 0x3409fcc8 start_wqthread + 0
Thread 3:
0 libsystem_kernel.dylib 0x319e7cd4 __workq_kernreturn + 8
1 libsystem_c.dylib 0x3409ff36 _pthread_wqthread + 610
2 libsystem_c.dylib 0x3409fcc8 start_wqthread + 0
Thread 4 name: WebThread
Thread 4:
0 libsystem_kernel.dylib 0x319d7004 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x319d71fa mach_msg + 50
2 CoreFoundation 0x378043ec __CFRunLoopServiceMachPort + 120
3 CoreFoundation 0x37803124 __CFRunLoopRun + 876
4 CoreFoundation 0x3778649e CFRunLoopRunSpecific + 294
5 CoreFoundation 0x37786366 CFRunLoopRunInMode + 98
6 WebCore 0x3312fc9c RunWebThread(void*) + 396
7 libsystem_c.dylib 0x340a572e _pthread_start + 314
8 libsystem_c.dylib 0x340a55e8 thread_start + 0
Thread 5 name: com.apple.NSURLConnectionLoader
Thread 5:
0 libsystem_kernel.dylib 0x319d7004 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x319d71fa mach_msg + 50
2 CoreFoundation 0x378043ec __CFRunLoopServiceMachPort + 120
3 CoreFoundation 0x37803124 __CFRunLoopRun + 876
4 CoreFoundation 0x3778649e CFRunLoopRunSpecific + 294
5 CoreFoundation 0x37786366 CFRunLoopRunInMode + 98
6 Foundation 0x38016bb2 +[NSURLConnection(Loader) _resourceLoadLoop:] + 302
7 Foundation 0x38016a7a -[NSThread main] + 66
8 Foundation 0x380aa58a __NSThread__main__ + 1042
9 libsystem_c.dylib 0x340a572e _pthread_start + 314
10 libsystem_c.dylib 0x340a55e8 thread_start + 0
Thread 6 Crashed:
0 libsystem_kernel.dylib 0x319e7cd4 __workq_kernreturn + 8
1 libsystem_c.dylib 0x3409ff36 _pthread_wqthread + 610
2 libsystem_c.dylib 0x3409fcc8 start_wqthread + 0
Thread 7:
0 libsystem_kernel.dylib 0x319e7cd4 __workq_kernreturn + 8
1 libsystem_c.dylib 0x3409ff36 _pthread_wqthread + 610
2 libsystem_c.dylib 0x3409fcc8 start_wqthread + 0
Thread 8:
0 libsystem_kernel.dylib 0x319e7cd4 __workq_kernreturn + 8
1 libsystem_c.dylib 0x3409ff36 _pthread_wqthread + 610
2 libsystem_c.dylib 0x3409fcc8 start_wqthread + 0
Thread 9 name: com.apple.CFSocket.private
Thread 9:
0 libsystem_kernel.dylib 0x319e7570 __select + 20
1 CoreFoundation 0x3780863a __CFSocketManager + 726
2 libsystem_c.dylib 0x340a572e _pthread_start + 314
3 libsystem_c.dylib 0x340a55e8 thread_start + 0
Thread 6 crashed with ARM Thread State:
r0: 0x00000004 r1: 0x00000000 r2: 0x00000000 r3: 0x00000000
r4: 0x0c8cc800 r5: 0x0036a08c r6: 0x04339000 r7: 0x04338fe0
r8: 0x3f29fd30 r9: 0x00000000 r10: 0x3f29fd50 r11: 0x00000000
ip: 0x00000170 sp: 0x04338fc0 lr: 0x3409ff3d pc: 0x319e7cd4
cpsr: 0x40000010
Can anyone enlighten us with this crash report?
UPDATE:
We nagged the app review team to send us the console trace, they did. In the trace it was evident that a call is being made to a String category method that does not exists.
The fault was that the particular category implementation file was not added to our release target. So everything worked perfectly but when the app was archived an implementation file was missing.

Answer 1

Unfortunately this log doesn't look like it'll be too useful - it just shows the main thread handling an exception that's being re-thrown from another thread; that thread has gone off to do something else at the time of the log.
You mention your suspicion about the RestKit loop and the possibility NSOperation is throwing the exception. That's possible and worth putting a check in (and crossing your fingers that it doesn't break something else...), but it's probably time to beg the app review team to give you better steps to reproduce. See if you can pin down what you all are doing differently. I wish I had a better answer for you, but I think exploring all you can about what you're doing in the background while in this part of the app and trying to figure out the missing steps to reproduce is going to be your best bet. Good luck!

Answer 2

The crash happened in Thread 0 at the top most Snug line 4
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0:
0 libsystem_kernel.dylib 0x319e7660 __semwait_signal_nocancel + 24
1 libsystem_c.dylib 0x3410b4da nanosleep$NOCANCEL + 118
2 libsystem_c.dylib 0x340dd3a0 usleep$NOCANCEL + 44
3 libsystem_c.dylib 0x340dd2b6 abort + 118
4 Snug 0x001f8760 uncaught_exception_handler + 12
5 CoreFoundation 0x37830950 __handleUncaughtException + 68
6 libobjc.A.dylib 0x3553533e _objc_terminate + 122
7 libc++abi.dylib 0x36f683be safe_handler_caller(void (*)()) + 70
8 libc++abi.dylib 0x36f6844a std::terminate() + 14
9 libc++abi.dylib 0x36f6981e __cxa_rethrow + 82
10 libobjc.A.dylib 0x355352a2 objc_exception_rethrow + 6
11 CoreFoundation 0x37786506 CFRunLoopRunSpecific + 398
12 CoreFoundation 0x37786366 CFRunLoopRunInMode + 98
13 GraphicsServices 0x33f45432 GSEventRunModal + 130
14 UIKit 0x31532cce UIApplicationMain + 1074
15 Snug 0x000f590c main (main.m:16)
16 Snug 0x000f58c0 start + 32
There the app caused an exception which was not caught.
To symbolicate the report just drag it into xCode - you need to have the dSYM file for the reviewed version. Then xCode will show you the exact line where the problem occured. To get the dSym you need to "build and archive".
Also since the crash code is
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x00000000, 0x00000000
the reason for the crash is a memory access problem. These kind of crash reports are generated in many cases where one tries to instert a nil object into an array or dictionary. (since the crash is in the main thread and not in Thread 6 as reported)
In your case I do not see any obvious insert, however I would check the logic starting in line 16 of your main file and all the subsequent. I would assume you are accessing an object which is not existent anymore at the time of this invokation.

Answer 3

You can analyze the crash report using the below
Steps to analyze crash report from apple:
Copy the release .app file which was pushed to the appstore, the .dSYM file that was created at the time of release and the crash report receive from APPLE into a FOLDER.
OPEN terminal application and go to the folder created above (using CD command)
atos -arch armv7 -o YOURAPP.app/YOURAPP MEMORY_LOCATION_OF_CRASH. The memory location should be the one at which the app crashed as per the report.
Ex: atos -arch armv7 -o 'app name.app'/'app name' 0x0003b508
This would show you the exact line, method name which resulted in crash.
Ex: [classname functionName:]; -510
Symbolicating IPA
if we use IPA for symbolicating - just rename the extention .ipa with .zip , extract it then we can get a Payload Folder which contain app. In this case we don't need .dSYM file.
Link for this Symbolicating iPhone App Crash Reports