I have the following crash that I can't replicate on demand but does happen enough to get noticed by the users.
This crash report has been symbolicated as well. How would you find out the cause!!! This only seems to happen on 4.1
Exception Type: SIGSEGV Exception Codes: SEGV_ACCERR at 0x9f069184 Crashed Thread: 0 Thread 0 Crashed: 0 libobjc.A.dylib 0x000027d8 objc_msgSend + 16 1 CoreFoundation 0x0007d749 ____CFXNotificationPost_old_block_invoke_1 + 45 2 libSystem.B.dylib 0x000d5984 _dispatch_call_block_and_release + 20 3 libSystem.B.dylib 0x000d66b0 _dispatch_continuation_pop + 72 4 libSystem.B.dylib 0x000d69fc _dispatch_main_queue_callback_4CF + 220 5 CoreFoundation 0x0002789b __CFRunLoopRun + 1335 6 CoreFoundation 0x00027277 CFRunLoopRunSpecific + 231 7 CoreFoundation 0x0002717f CFRunLoopRunInMode + 59 8 GraphicsServices 0x000045f3 GSEventRunModal + 115 9 GraphicsServices 0x0000469f GSEventRun + 63 10 UIKit 0x00004123 -[UIApplication _run] + 403 11 UIKit 0x0000212f UIApplicationMain + 671 12 MyApp 0x000024e3 main (main.m:17)
I have since managed to get a little more info, but not much.
2012-02-12 18:03:04.556 MyApp[462:307] (null): unrecognized selector sent to class 0x3e0a360c 2012-02-12 18:03:04.618 MyApp[462:307] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '(null): unrecognized selector sent to class 0x3e0a360c' *** Call stack at first throw: ( 0 CoreFoundation 0x33506ed3 __exceptionPreprocess + 114 1 libobjc.A.dylib 0x30412811 objc_exception_throw + 24 2 CoreFoundation 0x335086ff +[NSObject(NSObject) doesNotRecognizeSelector:] + 102 3 CoreFoundation 0x334b01d9 ___forwarding___ + 508 4 CoreFoundation 0x334aff90 _CF_forwarding_prep_0 + 48 5 Foundation 0x302a86b3 _nsnote_callback + 142 6 CoreFoundation 0x334e4749 ____CFXNotificationPost_old_block_invoke_1 + 44 7 libSystem.B.dylib 0x31d05984 _dispatch_call_block_and_release + 20 8 libSystem.B.dylib 0x31d066b0 _dispatch_continuation_pop + 72 9 libSystem.B.dylib 0x31d069fc _dispatch_main_queue_callback_4CF + 220 10 CoreFoundation 0x3348e89b __CFRunLoopRun + 1334 11 CoreFoundation 0x3348e277 CFRunLoopRunSpecific + 230 12 CoreFoundation 0x3348e17f CFRunLoopRunInMode + 58 13 GraphicsServices 0x31b5e5f3 GSEventRunModal + 114 14 GraphicsServices 0x31b5e69f GSEventRun + 62 15 UIKit 0x341bd123 -[UIApplication _run] + 402 16 UIKit 0x341bb12f UIApplicationMain + 670
Now all of my addObservers are block based so I can't see why it would lead to an unrecognised selector.
This way won't help us much while Debugging crash. I found one of the best way to Debug the code for Crash. Follow the link for debugging technique:
You need to analyze your Console very carefully to see actually why the Crash occurs. This helped me in almost all of the Code that are without ARC enabled.
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