On CI_DRM_3040, the machine shard-hsw, the test igt@kms_flip@flip-vs-modeset-interruptible generated the following dmesg:

[   50.826884] [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A
[   50.826963] [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun
[   50.877032] pipe C vblank wait timed out
[   50.877065] ------------[ cut here ]------------
[   50.877116] WARNING: CPU: 7 PID: 2550 at drivers/gpu/drm/i915/intel_display.c:12179 intel_atomic_commit_tail+0xf1d/0xf40 [i915]
[   50.877120] Modules linked in: snd_hda_codec_hdmi i915 snd_hda_codec_realtek snd_hda_codec_generic x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_intel snd_hda_codec crct10dif_pclmul crc32_pclmul snd_hwdep snd_hda_core ghash_clmulni_intel snd_pcm mei_me r8169 prime_numbers mii lpc_ich mei
[   50.877194] CPU: 7 PID: 2550 Comm: kms_flip Tainted: G     U          4.13.0-CI-CI_DRM_3040+ #1
[   50.877198] Hardware name: MSI MS-7924/Z97M-G43(MS-7924), BIOS V1.12 02/15/2016
[   50.877202] task: ffff8803fa6d2800 task.stack: ffffc90000fcc000
[   50.877249] RIP: 0010:intel_atomic_commit_tail+0xf1d/0xf40 [i915]
[   50.877253] RSP: 0018:ffffc90000fcfac0 EFLAGS: 00010282
[   50.877260] RAX: 000000000000001c RBX: 0000000000000002 RCX: 0000000000000001
[   50.877264] RDX: 0000000080000001 RSI: ffffffff81d021bf RDI: 00000000ffffffff
[   50.877267] RBP: ffffc90000fcfb70 R08: ffff8803fa6d3118 R09: 0000000000000000
[   50.877271] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8803f9780000
[   50.877274] R13: 0000000000000430 R14: 0000000000000008 R15: 0000000000000004
[   50.877279] FS:  00007fcd4295da40(0000) GS:ffff88041fbc0000(0000) knlGS:0000000000000000
[   50.877282] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   50.877286] CR2: 00007f568a836000 CR3: 00000004064ac000 CR4: 00000000001406e0
[   50.877290] Call Trace:
[   50.877303]  ? wait_woken+0x90/0x90
[   50.877350]  intel_atomic_commit+0x1bd/0x280 [i915]
[   50.877359]  drm_atomic_commit+0x4b/0x50
[   50.877365]  drm_atomic_helper_set_config+0x81/0x90
[   50.877372]  __drm_mode_set_config_internal+0x65/0x110
[   50.877379]  drm_mode_setcrtc+0x4c8/0x630
[   50.877386]  ? drm_modeset_acquire_fini+0x1f/0x60
[   50.877392]  ? drm_mode_page_flip_ioctl+0x269/0x530
[   50.877405]  ? drm_mode_getcrtc+0x180/0x180
[   50.877410]  drm_ioctl_kernel+0x69/0xb0
[   50.877417]  drm_ioctl+0x2f9/0x3d0
[   50.877422]  ? drm_mode_getcrtc+0x180/0x180
[   50.877435]  ? __vfs_read+0x28/0x120
[   50.877443]  do_vfs_ioctl+0x94/0x670
[   50.877450]  ? entry_SYSCALL_64_fastpath+0x5/0xb1
[   50.877457]  ? __this_cpu_preempt_check+0x13/0x20
[   50.877463]  ? trace_hardirqs_on_caller+0xe3/0x1b0
[   50.877470]  SyS_ioctl+0x41/0x70
[   50.877477]  entry_SYSCALL_64_fastpath+0x1c/0xb1
[   50.877481] RIP: 0033:0x7fcd40b5c587
[   50.877485] RSP: 002b:00007ffdd81615d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[   50.877492] RAX: ffffffffffffffda RBX: ffffffff8148a693 RCX: 00007fcd40b5c587
[   50.877496] RDX: 00007ffdd8161610 RSI: 00000000c06864a2 RDI: 0000000000000003
[   50.877499] RBP: ffffc90000fcff88 R08: 0000000000000000 R09: 00007ffdd8161ab8
[   50.877503] R10: 00007ffdd8161964 R11: 0000000000000246 R12: 0000000000000000
[   50.877506] R13: 0000000000000003 R14: 00000000c06864a2 R15: 0000000000000003
[   50.877513]  ? __this_cpu_preempt_check+0x13/0x20
[   50.877522] Code: ff ff ff 48 83 c7 08 e8 12 2e d1 e0 4c 8b 85 78 ff ff ff 4d 85 c0 0f 85 d3 fd ff ff 8d 73 41 48 c7 c7 28 b9 46 a0 e8 c4 73 d3 e0 <0f> ff e9 bd fd ff ff 8d 70 41 48 c7 c7 f8 b8 46 a0 e8 ae 73 d3 
[   50.877716] ---[ end trace d7c4def1351a7d58 ]---

Full logs: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_3040/shard-hsw5/igt@kms_flip@flip-vs-modeset-interruptible.html