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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 - CNL unable to handle kernel paging request at 00000000fffffffc"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=103800">103800</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>CNL unable to handle kernel paging request at 00000000fffffffc
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>DRI
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>XOrg git
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>x86-64 (AMD64)
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux (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>DRM/Intel
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>rafael.antognolli@intel.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=135561" name="attach_135561" title="Dmesg output showing the error.">attachment 135561</a> <a href="attachment.cgi?id=135561&action=edit" title="Dmesg output showing the error.">[details]</a></span>
Dmesg output showing the error.

I can run into this issue by executing piglit on CNL with the following branch:

<a href="https://cgit.freedesktop.org/~rantogno/mesa/log/?h=wip/cnl_disable_pc">https://cgit.freedesktop.org/~rantogno/mesa/log/?h=wip/cnl_disable_pc</a>

The kernel emits a backtrace and the machine becomes unusable shortly after
(it's not a simple GPU hang). Even ssh eventually stops working.

It takes a couple tries to happen. I had it happen with other branches too, and
I believe master also has the same issue.

I was using drm-tip from today, commit hash:
74ae8acff97c1739330154fa34bf5a64e28d608f

I also artificially disabled preemption by setting .has_logical_ring_preemption
= 0 on GEN9_FEATURES. I'll re-enable it and confirm that the bug still happens
(just wanted to start the discussion early).

Steps to reproduce:

 - Disable gdm so that no X or gnome-wayland or anything like that is running
 - with the above kernel, the mentioned mesa branch, and piglit installed, run
something like:

$ EGL_PLATFORM=gbm PIGLIT_PLATFORM=gbm ./piglit run gpu ~/piglit_output/

Make sure you have mesa, waffle and piglit built with gbm support. I believe
the bug would also happen in other platforms too, like X or wayland.</pre>
        </div>
      </p>


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