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        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [GTK] Crash in WebKit::supportsXDamageAndXComposite"
   href="https://bugs.webkit.org/show_bug.cgi?id=146347">146347</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>[GTK] Crash in WebKit::supportsXDamageAndXComposite
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>WebKit
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>528+ (Nightly build)
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>Normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P2
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>WebKit Gtk
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>webkit-unassigned&#64;lists.webkit.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>mcatanzaro&#64;igalia.com
          </td>
        </tr></table>
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        <pre>Created <span class=""><a href="attachment.cgi?id=255638" name="attach_255638" title="full backtrace">attachment 255638</a> <a href="attachment.cgi?id=255638&amp;action=edit" title="full backtrace">[details]</a></span>
full backtrace

I'm not really sure what to make of this crash report, whether it's a WebKit issue or an X11 issue:

Truncated backtrace:
Thread no. 1 (10 frames)
 #0 XQueryExtension at QuExt.c:43
 #1 XInitExtension at InitExt.c:47
 #2 XDamageExtAddDisplay at Xdamage.c:58
 #3 XDamageFindDisplay at Xdamage.c:202
 #4 XDamageQueryExtension at Xdamage.c:288
 #5 WebKit::supportsXDamageAndXComposite at /usr/src/debug/webkitgtk-2.9.3/Source/WebKit2/UIProcess/gtk/RedirectedXCompositeWindow.cpp:115
 #6 WebKit::RedirectedXCompositeWindow::create(_GdkWindow*, std::function&lt;void ()&gt;) at /usr/src/debug/webkitgtk-2.9.3/Source/WebKit2/UIProcess/gtk/RedirectedXCompositeWindow.cpp:135
 #7 webkitWebViewBaseRealize at /usr/src/debug/webkitgtk-2.9.3/Source/WebKit2/UIProcess/API/gtk/WebKitWebViewBase.cpp:332
 #12 gtk_widget_realize at gtkwidget.c:5551
 #13 gtk_widget_map at gtkwidget.c:5066

QuExt.c is pretty simple [1]; looks like we may have passed an invalid display (dpy=dpy&#64;entry=0x55c3119500b0).

[1] <a href="http://cgit.freedesktop.org/xorg/lib/libX11/tree/src/QuExt.c">http://cgit.freedesktop.org/xorg/lib/libX11/tree/src/QuExt.c</a></pre>
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