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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Patch for dangling disp->DriverData pointer in error path"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=94710">94710</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Patch for dangling disp->DriverData pointer in error path
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>Mesa
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>11.1
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Other
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

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

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>EGL
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>mesa-dev@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>john@feith.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>mesa-dev@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=122571" name="attach_122571" title="Patch for problem.">attachment 122571</a> <a href="attachment.cgi?id=122571&action=edit" title="Patch for problem.">[details]</a></span>
Patch for problem.

Noticed while looking at a crash the following code pattern:

    dri2_dpy = calloc(1, sizeof *dri2_dpy);

    disp->DriverData = (void *) dri2_dpy;

    ...

    if error goto cleanup

    return success

  cleanup:
    free(dri2_dpy)

    return failure

The problem being that on failure disp->DriverData is left pointing to
memory which has already been freed.  Granted no one should be accessing
it after a failure, however if someone does then random things may occur.
The attached patch sets disp->DriverData to NULL on failure so that more
predictable behavior occurs if someone does happen to accesses it.</pre>
        </div>
      </p>
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