title: WebKitLegacy - [_WebSafeForwarder forwardInvocation:] application crash in iOS10.0.1
body: <p>I am getting the following crash only in iOS10.0.1. Its not giving me enough stack trace information. The only clue I have is , seems to be happening from WebView.Because it says "WebKitLegacy  - [_WebSafeForwarder forwardInvocation:] ".</p>
  
  <p>The crash log is given below. I have another crash group related to "updateSubviewsOfScrollContentViews" seems like all are related. </p>
  
  <p>Any suggestions on this very helpful. Like how to debug this issue ? Where might be the problem?</p>
  
  <pre><code>Exception Type:  SIGSEGV
  Exception Codes: SEGV_ACCERR at 0xcec18beb8
  Crashed Thread:  0
  
  Application Specific Information:
  objc_msgSend() selector name: addObject:   
  
  
   Thread 0 Crashed:
      0   libobjc.A.dylib                      0x000000018d9fef30 objc_msgSend + 16
      1   UIKit                                0x000000019502abd8 updateSubviewsOfScrollContentViews + 184
      2   UIKit                                0x000000019502acdc updateSubviewsOfScrollContentViews + 444
      3   UIKit                                0x000000019502acdc updateSubviewsOfScrollContentViews + 444
      4   UIKit                                0x000000019502acdc updateSubviewsOfScrollContentViews + 444
      5   UIKit                                0x000000019502acdc updateSubviewsOfScrollContentViews + 444
      6   UIKit                                0x000000019502aad0 -[UIWebBrowserView _collectAdditionalSubviews] + 380
      7   UIKit                                0x000000019502a924 -[UIWebDocumentView _updateSubviewCaches] + 52
      8   UIKit                                0x000000019500d268 -[UIWebDocumentView webViewDidCommitCompositingLayerChanges:] + 44
      9   UIKit                                0x000000019500cf80 -[UIWebBrowserView webViewDidCommitCompositingLayerChanges:] + 80
      10  CoreFoundation                       0x000000018efba160 __invoking___ + 140
      11  CoreFoundation                       0x000000018eeadc3c -[NSInvocation invoke] + 280
      12  CoreFoundation                       0x000000018eeb26ec -[NSInvocation invokeWithTarget:] + 56
      13  WebKitLegacy                         0x0000000194ae77f8 -[_WebSafeForwarder forwardInvocation:] + 152
      14  libdispatch.dylib                    0x000000018de3d200 _dispatch_call_block_and_release + 20
      15  libdispatch.dylib                    0x000000018de3d1c0 _dispatch_client_callout + 12
      16  libdispatch.dylib                    0x000000018de41d6c _dispatch_main_queue_callback_4CF + 996
      17  CoreFoundation                       0x000000018ef61f2c __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 8
      18  CoreFoundation                       0x000000018ef5fb18 __CFRunLoopRun + 1656
      19  CoreFoundation                       0x000000018ee8e048 CFRunLoopRunSpecific + 440
      20  GraphicsServices                     0x0000000190911198 GSEventRunModal + 176
      21  UIKit                                0x0000000194e67818 -[UIApplication _run] + 680
      22  UIKit                                0x0000000194e62550 UIApplicationMain + 204
      23  Essentials                           0x00000001000f5f08 main (main.m:52)
      24  ???                                  0x000000018de705b8 0x0 + 0enter code here
  </code></pre>