<html>
    <head>
      <base href="https://bugs.freedesktop.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Segmentation fault in Gnome Shell when resuming from blank screen"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=107520">107520</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Segmentation fault in Gnome Shell when resuming from blank screen
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>18.1
          </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>Drivers/DRI/i965
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>intel-3d-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>pbasista@gmail.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-3d-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=141004" name="attach_141004" title="full backtrace of gnome-shell crashing on SIGSEGV in image_get_buffers">attachment 141004</a> <a href="attachment.cgi?id=141004&action=edit" title="full backtrace of gnome-shell crashing on SIGSEGV in image_get_buffers">[details]</a></span>
full backtrace of gnome-shell crashing on SIGSEGV in image_get_buffers

When resuming from blank screen in Gnome Shell (can be configured in
Settings->Power), Gnome Shell process sometimes (around 40% to 50% of cases in
my experience) crashes on segmentation fault. The backtraces vary slightly, but
mostly they point to intel_update_image_buffers function in the
src/mesa/drivers/dri/i965/brw_context.c file.

There is a related bug report on Gnome Bugzilla:

<a href="https://bugzilla.gnome.org/show_bug.cgi?id=795537">https://bugzilla.gnome.org/show_bug.cgi?id=795537</a>

One person suggested that a crash inside mesa should never happen, so I am
reporting it here as well.

One of the backtraces that I have starts like this:

Core was generated by `/usr/bin/gnome-shell'.
Program terminated with signal SIGSEGV, Segmentation fault.

#0  0x00007f74143eed33 in image_get_buffers (driDrawable=0x56353e8ca4d0,
format=4098, stamp=0x56353e8ca500, loaderPrivate=0x56353e8d4510, buffer_mask=1,
buffers=0x7ffd94a282c0)
    at ../../../src/gbm/backends/dri/gbm_dri.c:132
#1  0x00007f7405c29741 in intel_update_image_buffers (drawable=0x56353e8ca4d0,
brw=0x56353e7a9980) at
../../../../../../src/mesa/drivers/dri/i965/brw_context.c:1751
#2  intel_update_renderbuffers (context=context@entry=0x56353e7c82d0,
drawable=drawable@entry=0x56353e8ca4d0) at
../../../../../../src/mesa/drivers/dri/i965/brw_context.c:1427
#3  0x00007f7405c29dc1 in intel_prepare_render (brw=brw@entry=0x56353e7a9980)
at ../../../../../../src/mesa/drivers/dri/i965/brw_context.c:1448
#4  0x00007f7405c2c012 in brw_prepare_drawing (max_index=4294967295,
min_index=0, index_bounds_valid=<optimized out>, ib=0x7ffd94a28430,
arrays=<optimized out>, ctx=0x56353e7a9980)
    at ../../../../../../src/mesa/drivers/dri/i965/brw_draw.c:730
#5  brw_draw_prims (ctx=0x56353e7a9980, prims=0x7ffd94a28450, nr_prims=1,
ib=0x7ffd94a28430, index_bounds_valid=<optimized out>, min_index=<optimized
out>, max_index=<optimized out>, 
    gl_xfb_obj=0x0, stream=0, indirect=0x0) at
../../../../../../src/mesa/drivers/dri/i965/brw_draw.c:992
#6  0x00007f74059c1b59 in vbo_validated_drawrangeelements (ctx=<optimized out>,
mode=<optimized out>, index_bounds_valid=<optimized out>, start=0,
end=<optimized out>, 
    count=<optimized out>, type=5123, indices=0x0, basevertex=0,
numInstances=1, baseInstance=0) at ../../../src/mesa/vbo/vbo_exec_array.c:843
#7  0x00007f74059c252e in vbo_exec_DrawElements (mode=4, count=1302, type=5123,
indices=0x0) at ../../../src/mesa/vbo/vbo_exec_array.c:1001


The full version is attached.</pre>
        </div>
      </p>


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