title: iPhone crash log help, GPUImage/UIScrollView related
body: <p>I'm getting very random bugs that only occur a couple of times a day with heavy testing. I have a <code>UIScrollView</code> with some preview images of filter choices, and when the user stops scrolling in this <code>UIScrollView</code>, whichever image is highlighted, that respective filter previews gets applied to the image showing in a <code>UIImageView</code>. I've provided a crash log below for the respective thread that crashed (not the other threads in the crash log), but if you need more information please let me know. </p>
  
  <p>Any help in understanding this crash log is always appreciated.</p>
  
  <pre><code>Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
  Exception Subtype: KERN_INVALID_ADDRESS at 0x00000005
  Triggered by Thread:  0
  
  Thread 0 Crashed:
  0   CoreFoundation                  0x2edbe47e CFGetTypeID + 6
  1   CoreVideo                       0x2f5dd114 _getCVPixelBuffer + 12
  2   CoreVideo                       0x2f5dd1dc CVPixelBufferGetBytesPerRow + 4
  3   TheApp                          0x00168348 0xe9000 + 521032
  4   libdispatch.dylib               0x39b11d3c _dispatch_client_callout + 20
  5   libdispatch.dylib               0x39b1656a _dispatch_barrier_sync_f_slow + 226
  6   TheApp                          0x000f89b6 0xe9000 + 63926
  7   TheApp                          0x00168268 0xe9000 + 520808
  8   TheApp                          0x00162f8e 0xe9000 + 499598
  9   TheApp                          0x000f9638 0xe9000 + 67128
  10  TheApp                          0x0017b31c 0xe9000 + 598812
  11  TheApp                          0x00179c10 0xe9000 + 592912
  12  UIKit                           0x316f2c80 -[UIScrollView _endPanNormal:] + 1536
  13  UIKit                           0x31856d0c -[UIScrollView handlePan:] + 116
  14  UIKit                           0x318457f4 _UIGestureRecognizerSendActions + 192
  15  UIKit                           0x316f0a8e -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:] + 1134
  16  UIKit                           0x31a980ba ___UIGestureRecognizerUpdate_block_invoke + 42
  17  UIKit                           0x316b794c _UIGestureRecognizerRemoveObjectsFromArrayAndApplyBlocks + 216
  18  UIKit                           0x316b60ae _UIGestureRecognizerUpdate + 294
  19  UIKit                           0x316ef300 -[UIWindow _sendGesturesForEvent:] + 768
  20  UIKit                           0x316eec26 -[UIWindow sendEvent:] + 662
  21  UIKit                           0x316c3e50 -[UIApplication sendEvent:] + 192
  22  UIKit                           0x316c251c _UIApplicationHandleEventQueue + 7116
  23  CoreFoundation                  0x2ee58fac __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 12
  24  CoreFoundation                  0x2ee58472 __CFRunLoopDoSources0 + 202
  25  CoreFoundation                  0x2ee56c62 __CFRunLoopRun + 626
  26  CoreFoundation                  0x2edc1724 CFRunLoopRunSpecific + 520
  27  CoreFoundation                  0x2edc1506 CFRunLoopRunInMode + 102
  28  GraphicsServices                0x33d306ce GSEventRunModal + 134
  29  UIKit                           0x3172286c UIApplicationMain + 1132
  30  TheApp                          0x001c18e2 0xe9000 + 887010
  31  libdyld.dylib                   0x39b26ab4 start + 0
  </code></pre>