One note: I used 8677 on minnie over weekend with no problem.

8683 on minnie also has no problems.  I've only seen the problems with cyan right now.

cyan frecon doesn't start with 
[    1.974301] frecon(506): Frecon using drm driver i915, version 1.6, date(20150717), desc(Intel Graphics)
[    7.411646] frecon(506): Chrome started, splash screen is not needed anymore.
[ 1260.505388] frecon(506): Could not set master when switching to foreground Invalid argument.
[ 1260.660233] frecon(506): Unable to set crtc: Permission denied
[ 1260.660690] frecon(506): drmModeDirtyFB failed: Permission denied


network is reachable so I can ssh into it still, console is unusable.

It looks like a number of kernel patches for the DRM subsystem landed on Friday. After filtering out some CLs specific to other platforms:

590c4da BACKPORT/FROMLIST: drm/plane-helper: Add drm_plane_helper_check_state()
a9b61d2 FROMLIST: drm: Warn about negative sizes when calculating scale factor
2e279b9 BACKPORT: drm: Deal with rotation in drm_plane_helper_check_update()
00bad88 UPSTREAM: drm/armada: convert overlay to use drm_plane_helper_check_update()
f2fe6a6 UPSTREAM: drm: Print the src/dst/clip rectangles in error in drm_plane_helper
d057172 UPSTREAM: drm: Add "prefix" parameter to drm_rect_debug_print()
f4472ef UPSTREAM: drm: Fix primary plane size for stereo doubled modes for legacy setcrtc
acb5131 UPSTREAM: drm: Swap w/h when converting the mode to src coordidates for a rotated primary plane
86b6d02 UPSTREAM: drm/fb-helper: atomic restore_fbdev_mode()..
67c103864 UPSTREAM: drm/fb-helper: Use -errno return in restore_mode_unlocked
f5eac20 UPSTREAM: drm/fb_helper: move deferred fb checking into restore mode (v2)
0ede3ce UPSTREAM: drm/atomic: Paper over locking WARN in default_state_clear
8c75f1e UPSTREAM: drm/atomic: Clear crtcs, connectors and planes when clearing state

I hear chrome might already have started, looked into /var/log/ui/ui, some suspicious log:

[1823:1823:0808/140117:ERROR:gpu_info_collector_ozone.cc(11)] Not implemented reached in std::string gpu::CollectDriverVersionNVidia()
libva info: VA-API version 0.39.2
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib64/va/drivers/i965_drv_video.so
libva info: Found init function __vaDriverInit_0_39
libva info: va_openDriver() returns 0

 . 
 .

[3144:3152:0808/140118:ERROR:drm_device_manager.cc(53)] Could not initialize DRM device for /sys/devices/platform/vgem/drm/card1
[3144:3152:0808/140118:ERROR:hardware_display_plane_manager_legacy.cc(67)] Cannot page flip: crtc=32 framebuffer=59: No space left on device
[3144:3144:0808/140118:ERROR:gles2_cmd_decoder.cc(14145)] Context lost because SwapBuffers failed.
[3144:3144:0808/140118:ERROR:gles2_cmd_decoder.cc(4085)]   GLES2DecoderImpl: Trying to make lost context current.
 .
 .

flashed 8684.0.0 to samus and minnie and they are fine.

#8 would suggest that it's indeed related to the kernel patches listed above, since cyan uses 3.18 kernel, while samus and minnie are on 3.14.

8678.0.0 dev-channel test image on link works fine.

Duplicate: http://crosbug.com/p/56008

Fix is in 8686.0.0, but last successful cyan build seems to be still 8678.0.0 due to other issues on the builder.