title: App Crashes with EXC_BAD_INSTRUCTION (SIGILL)?
body: <p>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.</p>
  
  <p>After checking the crash log, Ii still can't find what the problem is and so, i come here to seek help.</p>
  
  <p>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.</p>
  
  <p>I can't reproduce the crash when i run the APP from XCode</p>
  
  <p>And I can's reproduce the crash when i newly install the APP from appStore</p>
  
  <p>Below is the crash log:</p>
  
  <pre><code>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
  </code></pre>