title: iOS 6 Maps occasional Crash
body: <p>I'm getting occasionally crash with iOS 6 MapKit. Can't really reproduce it. What can cause this?</p>
  
  <pre><code>Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
  Exception Codes: KERN_INVALID_ADDRESS at 0x00000044
  Crashed Thread:  0
  
  Thread 0 name:  Dispatch queue: com.apple.main-thread
  Thread 0 Crashed:
  0   IMGSGX543GLDriver               0x38f231b4 sgxTextureGetImageRowBytes(GLDTextureRec*, unsigned int, unsigned int) + 8
  1   IMGSGX543GLDriver               0x38f23160 CalculateChunkPlaneSizes(GLDTextureRec*, int, unsigned int*, unsigned int*, unsigned int*, unsigned int*) + 104
  2   IMGSGX543GLDriver               0x38f25906 sgxConfigureTexturePrivate(GLDTextureRec*) + 82
  3   IMGSGX543GLDriver               0x38f24584 glrUpdateTexture + 616
  4   libGPUSupportMercury.dylib      0x342c76b6 gldLoadFramebuffer + 102
  5   GLEngine                        0x31b50e52 gleUpdateDrawFramebufferState + 178
  6   GLEngine                        0x31b52556 gleDoDrawDispatchCoreES2 + 126
  7   GLEngine                        0x31aedbc0 gleDrawArraysOrElements_Entries_Body + 140
  8   GLEngine                        0x31aea5ec glDrawArrays_ES2Exec + 160
  9   VectorKit                       0x3780dcd6 -[VKSkyModel drawScene:withContext:] + 326
  10  VectorKit                       0x377e76d6 -[VKModelObject recursiveDrawScene:whenReadyWithContext:] + 118
  11  VectorKit                       0x377621ea -[VKMapModel recursiveDrawScene:withContext:] + 278
  12  VectorKit                       0x37762096 -[VKModelObject recursiveDrawScene:withContext:] + 186
  13  VectorKit                       0x3775d4da -[VKScreenCanvas onTimerFired:] + 1014
  14  VectorKit                       0x3775b548 -[VKMapCanvas onTimerFired:] + 500
  15  VectorKit                       0x3775a3d2 -[VKMainLoop displayTimerFired:] + 610
  16  QuartzCore                      0x3095b06c CA::Display::DisplayLink::dispatch(unsigned long long, unsigned long long) + 156
  17  QuartzCore                      0x3095afc4 CA::Display::IOMFBDisplayLink::callback(__IOMobileFramebuffer*, unsigned long long, unsigned long long, unsigned long long, void*) + 60
  18  IOMobileFramebuffer             0x331e4fd4 IOMobileFramebufferVsyncNotifyFunc + 152
  19  IOKit                           0x36fc4446 IODispatchCalloutFromCFMessage + 190
  20  CoreFoundation                  0x382a95d8 __CFMachPortPerform + 116
  21  CoreFoundation                  0x382b4170 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 32
  22  CoreFoundation                  0x382b4112 __CFRunLoopDoSource1 + 134
  23  CoreFoundation                  0x382b2f94 __CFRunLoopRun + 1380
  24  CoreFoundation                  0x38225eb8 CFRunLoopRunSpecific + 352
  25  CoreFoundation                  0x38225d44 CFRunLoopRunInMode + 100
  26  GraphicsServices                0x3415f2e6 GSEventRunModal + 70
  27  UIKit                           0x351b72fc UIApplicationMain + 1116
  28  MyApp                           0x0005d78a main (main.m:14)
  29  MyApp                           0x0005d744 start + 36
  </code></pre>