FYI, we noticed the following commit (built with gcc-7):

commit: 0ab3c0ebc06b87cdcf7a6a7595c1e02ae978bace ("[Intel-gfx] [CI HACK PATCH] HACK: drm/i915: see what breaks with display disabled")
url: https://github.com/0day-ci/linux/commits/Jani-Nikula/HACK-drm-i915-see-what-breaks-with-display-disabled/20180609-165922
base: git://anongit.freedesktop.org/drm-intel for-linux-next

in testcase: piglit
with following parameters:

	group: igt-basic

test-description: Piglit is a collection of automated tests for OpenGL implementations.
test-url: https://people.freedesktop.org/~nh/piglit/


on test machine: 8 threads Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 8G memory

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):




2018-06-13 15:56:29 piglit run igt -t igt.kms_addfb_basic.addfb25-framebuffer-vs-set-tiling /tmp/lkp/piglit-results -x igt.kms_addfb_basic.addfb25-framebuffer-vs-set-tiling.
[1/1] fail: 1 |
[1/1] fail: 1  

             
Thank you for running Piglit!
Results have been written to /tmp/lkp/piglit-results
igt.kms_addfb_basic.addfb25-framebuffer-vs-set-tiling.seconds: 4.492297596
2018-06-13 15:56:34 piglit summary console /tmp/lkp/piglit-results/results.json.bz2
igt/kms_addfb_basic/addfb25-framebuffer-vs-set-tiling: fail
summary:
       name: piglit-results
       ----  --------------
       pass:              0
       fail:              1
      crash:              0
       skip:              0
    timeout:              0
       warn:              0
 incomplete:              0
 dmesg-warn:              0
 dmesg-fail:              0
    changes:              0
      fixes:              0
regressions:              0
      total:              1
       time:       00:00:04
2018-06-13 15:56:34 piglit run igt -t igt.kms_addfb_basic.addfb25-x-tiled /tmp/lkp/piglit-results -x igt.kms_addfb_basic.addfb25-x-tiled.
[1/1] fail: 1 |
[1/1] fail: 1  

             

Thanks,
Xiaolong