title: iPhone Crash with "No Backtrace"
body: <p>My iPhone app was recently rejected from the App Store "because it crashes on launch". However, I cannot reproduce this crash. The app works perfectly on both the simulator and a device with the same hardware and software Apple tested it on (iPhone 3.1 running iOS 4). The crash logs they sent me say "No Backtrace Available", so I have nowhere to look in my code. Here's an example:</p>
  
  <pre><code>Incident Identifier: [...]
  CrashReporter Key:   [...]
  Hardware Model:      iPhone3,1
  Process:         [MyApp] [1172]
  Path:            /var/mobile/Applications/[...]-3F1B-4504-A572-[...]/[MyApp].app/[MyApp]
  Identifier:      [MyApp]
  Version:         ??? (???)
  Code Type:       ARM (Native)
  Parent Process:  launchd [1]
  
  Date/Time:       2010-07-08 [...]
  OS Version:      iPhone OS 4.0 (8A293)
  Report Version:  104
  
  Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
  Exception Codes: KERN_INVALID_ADDRESS at 0xfe42c648
  Highlighted Thread:  0
  
  Backtrace not available
  
  Unknown thread crashed with ARM Thread State:
      r0: 0x00002388    r1: 0x00000000      r2: 0x3e2b47c8      r3: 0x00000108
      r4: 0x2fe00000    r5: 0x00000000      r6: 0x00000000      r7: 0x00000000
      r8: 0x2ffffb48    r9: 0x2fffecfc     r10: 0x00000000     r11: 0x00000000
      ip: 0x00000010    sp: 0x2ffffb4c      lr: 0x2fe08907      pc: 0xfe42c648
    cpsr: 0x40000010
  
  Binary Images:
      0x1000 -    0x78fff +[MyApp] armv7  &lt;23af3d265c3086eaceb51cc649eb794f&gt; /var/mobile/Applications/[...]-3F1B-4504-A572-[...]/[MyApp].app/[MyApp]
  0x2fe00000 - 0x2fe26fff  dyld armv7  &lt;697ae459733a7f0b6c439b21ba62b110&gt; /usr/lib/dyld
  [many more libraries...]
  </code></pre>
  
  <p>How can I begin debugging this? Is it possible this is a build issue rather than a coding bug? And can I extract any useful information from the "ARM Thread State" or the "Binary Images" portions of the crash report?</p>
  
  <p>Thanks!</p>
  
  <p>*update: * I have installed the app for the first time on another iPhone running iOS 4 and still cannot reproduce the crash. I'm beginning to think this is an issue with build-time parameters such as libraries or targeted versions. Based on the crash report, is it likely that any of my application's code was executed? </p>