Debugging a EXEC_BAD_ACCESS on iOS

Question

I have a very strange EXEC_BAD_ACCESS error, the error happens on application start. No breakpoint or NSLog was reached it cancels when UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class])) get called.

It only crashes on simulator not on the device or with instruments. Zombies give me no informations, when I enable GUARDMALLOC on simulator it doesnt crash. The EXEC_BAD_ACCESS happens always on the same memory address.

I can get following backtrace

#0  0xcd58a2f6 in ?? ()
#1  0x0102b524 in -[UIWindow _commonInit] ()
#2  0x0102b66f in -[UIWindow initWithFrame:] ()
#3  0x0137be58 in -[UIStatusBarWindow initWithFrame:] ()
#4  0x0103c28f in -[UIView init] ()
#5  0x01000a5e in -[UIApplication _createStatusBarWithRequestedStyle:orientation:hidden:] ()
#6  0x00ffbe6b in -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] ()
#7  0x0100d315 in -[UIApplication handleEvent:withNewEvent:] ()
#8  0x0100e24b in -[UIApplication sendEvent:] ()
#9  0x00fffcf8 in _UIApplicationHandleEvent ()
#10 0x02fe7df9 in _PurpleEventCallback ()
#11 0x02fe7ad0 in PurpleEventCallback ()
#12 0x022cabf5 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ ()
#13 0x022ca962 in __CFRunLoopDoSource1 ()
#14 0x022fbbb6 in __CFRunLoopRun ()
#15 0x022faf44 in CFRunLoopRunSpecific ()
#16 0x022fae1b in CFRunLoopRunInMode ()
#17 0x00ffb7da in -[UIApplication _run] ()
#18 0x00ffd65c in UIApplicationMain ()
#19 0x00002ea2 in main (argc=1, argv=0xbffff2a0) at /Users/user/Projects/App/App/main.m:16

When I try to get informations about the memory I get

Cannot access memory at address 0xcd58a2f6

I can resolve it sometimes when I change some code but it happens again when I only create a local variable in some other functions, so I think the problem lays a bit deeper.

I'm a bit confused because didFinishLaunchingWithOptions never get reached when the error occurs, so what sort of influence can have code in my viewcontrollers?

As 3rd party components I use Phonegap 2.1 as a component and Reachability from Apple.

Answer 1

You can add exception breakpoints to get the location of the error. Here is a nice link of tutorial for the same. Hope it works for you.

Link is here.

Answer 2

Assuming it is not an xib issue, you could use atos (address to symbol) debugging to help you find the location of the issue.

A good tutorial on this method is available at http://saveme-dot-txt.blogspot.com/2011/04/using-atos-for-reading-crash-logs.html