iPhone App get random crash on iOS 4.0 or higher.

Question

I'm facing a random crash with my App on iPhone. Here is the crash log which makes me feel it probably related to thread-safe or UI behavior issues.

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x60000008
Crashed Thread:  0

Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libobjc.A.dylib                 0x30de0c98 0x30dde000 + 11416
1   UIKit                           0x335e0ec2 0x335c4000 + 118466
2   UIKit                           0x3366dc1a 0x335c4000 + 695322
3   CoreFoundation                  0x3683456a 0x36826000 + 58730
4   UIKit                           0x335e0ec2 0x335c4000 + 118466
5   UIKit                           0x335e0e62 0x335c4000 + 118370
6   UIKit                           0x335e0e34 0x335c4000 + 118324
7   UIKit                           0x335e0b86 0x335c4000 + 117638
8   UIKit                           0x335e141c 0x335c4000 + 119836
9   UIKit                           0x335dfbee 0x335c4000 + 113646
10  UIKit                           0x335df568 0x335c4000 + 111976
11  UIKit                           0x335c830c 0x335c4000 + 17164
12  UIKit                           0x335c7c4c 0x335c4000 + 15436
13  GraphicsServices                0x31623e70 0x3161f000 + 20080
14  CoreFoundation                  0x3689ba90 0x36826000 + 481936
15  CoreFoundation                  0x3689d838 0x36826000 + 489528
16  CoreFoundation                  0x3689e606 0x36826000 + 493062
17  CoreFoundation                  0x3682eebc 0x36826000 + 36540
18  CoreFoundation                  0x3682edc4 0x36826000 + 36292
19  GraphicsServices                0x31623418 0x3161f000 + 17432
20  GraphicsServices                0x316234c4 0x3161f000 + 17604
21  UIKit                           0x335f2d62 0x335c4000 + 191842
22  UIKit                           0x335f0800 0x335c4000 + 182272
23  Tapatalk X                      0x00002fa6 0x1000 + 8102
24  Tapatalk X                      0x00002f3c 0x1000 + 7996

Sometimes I find global variables get corrupted randomly too.

Any suggestion how I can trace down this issue or what tools can help? Thanks!

Answer 1

EXEC_BAD_ACCESS is usually caused by an attempt to access an already deallocated object. You can get more information in two ways:

1. execute the program in debug mode, so when it crashes you will be able to see the stack content;

2. activate NSZombies or run the program using the performance tool Zombies; this will tell you exactly which object was accessed after its deallocation.

From your crash report is very difficult to understand what is happening ,since it does not show method names... what is tapatalk?