Comment 6 for bug 1787260

Still present on 4.18:

$ dmesg | grep -FB3 -A50 ' cut here '
[ 0.776810] shpchp: Standard Hot Plug PCI Controller Driver version: 0.4
[ 0.776847] efifb: probing for efifb
[ 0.776849] efifb: cannot reserve video memory at 0xe0000000
[ 0.776851] ------------[ cut here ]------------
[ 0.776853] ioremap on RAM at 0x00000000e0000000 - 0x00000000e12fffff
[ 0.776859] WARNING: CPU: 4 PID: 1 at arch/x86/mm/ioremap.c:166 __ioremap_caller+0x2bc/0x2d0
[ 0.776861] Modules linked in:
[ 0.776863] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 4.18.0-041800-generic #201808122131
[ 0.776865] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X370 Taichi, BIOS P4.70 04/17/2018
[ 0.776868] RIP: 0010:__ioremap_caller+0x2bc/0x2d0
[ 0.776870] Code: 0f b7 05 a9 51 3c 01 49 09 c7 e9 f1 fe ff ff 48 8d 55 c8 48 8d 75 b8 48 c7 c7 7d 2c ae ac c6 05 d2 c6 5b 01 01 e8 26 78 01 00 <0f> 0b 31 db e9 64 ff ff ff e8 76 75 01 00 66 0f 1f 44 00 00 0f 1f
[ 0.776886] RSP: 0018:ffffb3cbc005fbd8 EFLAGS: 00010286
[ 0.776887] RAX: 0000000000000000 RBX: 0000000000000001 RCX: fffffffface62608
[ 0.776889] RDX: 0000000000000001 RSI: 0000000000000092 RDI: 0000000000000246
[ 0.776891] RBP: ffffb3cbc005fc40 R08: 0000000000000000 R09: 000000000000029c
[ 0.776893] R10: ffff9a77ce949f00 R11: 0766073207310765 R12: 00000000e0000000
[ 0.776894] R13: 0000000001300000 R14: 0000000001300000 R15: 0000000001300000
[ 0.776896] FS: 0000000000000000(0000) GS:ffff9a77ced00000(0000) knlGS:0000000000000000
[ 0.776898] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.776900] CR2: 0000000000000000 CR3: 00000001a6c0a000 CR4: 00000000003406e0
[ 0.776901] Call Trace:
[ 0.776906] ? _cond_resched+0x19/0x30
[ 0.776909] ? efifb_probe.cold.5+0x2db/0x55f
[ 0.776912] ioremap_wc+0x17/0x20
[ 0.776914] efifb_probe.cold.5+0x2db/0x55f
[ 0.776917] platform_drv_probe+0x3d/0x90
[ 0.776919] driver_probe_device+0x2e3/0x460
[ 0.776921] __driver_attach+0xe4/0x110
[ 0.776923] ? driver_probe_device+0x460/0x460
[ 0.776925] bus_for_each_dev+0x74/0xb0
[ 0.776929] ? kmem_cache_alloc_trace+0x1c4/0x1d0
[ 0.776931] driver_attach+0x1e/0x20
[ 0.776932] bus_add_driver+0x159/0x230
[ 0.776936] ? vesafb_driver_init+0x19/0x19
[ 0.776939] ? do_early_param+0x95/0x95
[ 0.776941] driver_register+0x70/0xc0
[ 0.776943] ? vesafb_driver_init+0x19/0x19
[ 0.776945] __platform_driver_register+0x36/0x40
[ 0.776947] efifb_driver_init+0x17/0x19
[ 0.776950] do_one_initcall+0x4a/0x1c4
[ 0.776952] ? do_early_param+0x95/0x95
[ 0.776954] kernel_init_freeable+0x1b7/0x261
[ 0.776957] ? rest_init+0xb0/0xb0
[ 0.776958] kernel_init+0xe/0x104
[ 0.776960] ret_from_fork+0x22/0x40
[ 0.776963] ---[ end trace 1748f2102269e213 ]---
[ 0.776965] efifb: abort, cannot ioremap video memory 0x1300000 @ 0xe0000000
[ 0.776969] efi-framebuffer: probe of efi-framebuffer.0 failed with error -5
[ 0.777053] input: Power Button as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0C:00/input/input0
[ 0.777061] ACPI: Power Button [PWRB]
[ 0.777085] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input1
[ 0.777096] ACPI: Power Button [PWRF]
[ 0.777142] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)
[ 0.777243] [Firmware Bug]: ACPI MWAIT C-state 0x0 not supported by HW (0x0)

I think the MWAIT firmware bug was not reported before this oops first occurred (although I would normally assume they are unrelated).