App Crashes with EXC_BAD_INSTRUCTION (SIGILL)?

Yesterday, I released a new version of my app and today i found, a lot of users that upgraded form old version, encountered a crash.

After checking the crash log, Ii still can't find what the problem is and so, i come here to seek help.

The crash log shows, an unknown thread crash, and it looks like the APP have not finish launch, and none of my code was running.

I can't reproduce the crash when i run the APP from XCode

And I can's reproduce the crash when i newly install the APP from appStore

Below is the crash log:

Incident Identifier: 7E991A17-1EAE-41CD-9B5D-ED915DEEB149
CrashReporter Key:   18ac1fb1671fd0ac6d2bde874eca5e132946f8f7
Hardware Model:      iPhone3,1
Process:         YoudaoDictNormal [3843]
Path:            /var/mobile/Applications/1FE76C37-584F-4D8B-A700-E72582DFB0ED/YoudaoDictNormal. app/YoudaoDictNormal
Identifier:      YoudaoDictNormal
Version:         ??? (???)
Code Type:       ARM (Native)
Parent Process:  launchd [1]


Date/Time:       2013-07-16 00:12:21.128 +0800
OS Version:      iOS 6.1.2 (10B146)
Report Version:  104


Exception Type:  EXC_BAD_INSTRUCTION (SIGILL)
Exception Codes: 0x0000000000000001, 0x000000000000b6d2
Highlighted Thread:  1


Thread 0 name:  Dispatch queue: com.apple.libdispatch-manager
Thread 0:
0   libsystem_kernel.dylib                  0x3bda7648 kevent64 + 24
1   libdispatch.dylib                       0x3bce04ec _dispatch_mgr_invoke + 792
2   libdispatch.dylib                       0x3bcd2df4 _dispatch_mgr_thread$VARIANT$up + 32


Thread 1:
0   libsystem_kernel.dylib                  0x3bdb7d98 __workq_kernreturn + 8
1   libsystem_c.dylib                       0x3bd05cf6 _pthread_workq_return + 14
2   libsystem_c.dylib                       0x3bd05a12 _pthread_wqthread + 362
3   libsystem_c.dylib                       0x3bd058a0 start_wqthread + 4


Thread 2:
0   libsystem_kernel.dylib                  0x3bdb7d98 __workq_kernreturn + 8
1   libsystem_c.dylib                       0x3bd05cf6 _pthread_workq_return + 14
2   libsystem_c.dylib                       0x3bd05a12 _pthread_wqthread + 362
3   libsystem_c.dylib                       0x3bd058a0 start_wqthread + 4


Unknown thread crashed with ARM Thread State (32-bit):
    r0: 0x000a50f8    r1: 0x2fd68cd4      r2: 0x000a4fd4      r3: 0x2fd68d08
    r4: 0x2ff0614c    r5: 0x2ff060ec      r6: 0x000a4ebd      r7: 0x0000002f
    r8: 0x2ff086ac    r9: 0x0000ab00     r10: 0x00000000     r11: 0x00000049
    ip: 0x1c52c200    sp: 0x2fd67a20      lr: 0x2fef251d      pc: 0x000a4e88
  cpsr: 0x80000030

There's not much information here, as others pointed out, but this appears to be a problem when upgrading. You didn't mention how you tested this, but you should test it basically like this:

• Use two projects, one with the previously released version, and one with the new one.
• Run the previously released version of the app. Do some typical stuff, then close.
• Now run the new verion of the app.

If there is an upgrade problem, you should be able to trigger it this way.