Comment 8 for bug 1769053

BTW this is the stacktrace I get from a Xenial guest on Xenial host:

[ 0.000000] BUG: unable to handle kernel paging request at ffffc90000000004
[ 0.000000] IP: [<ffffffff81f7dc60>] hpet_enable.part.13+0x23/0x2a5
[ 0.000000] PGD 171629ab067 PUD 171629ac067 PMD 171629ad067 PTE 80000000fed00073
[ 0.000000] Oops: 0009 [#1] SMP
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-122-generic #146-Ubuntu
[ 0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 0.000000] task: ffffffff81e13500 ti: ffffffff81e00000 task.ti: ffffffff81e00000
[ 0.000000] RIP: 0010:[<ffffffff81f7dc60>] [<ffffffff81f7dc60>] hpet_enable.part.13+0x23/0x2a5
[ 0.000000] RSP: 0000:ffffffff81e03ef0 EFLAGS: 00010282
[ 0.000000] RAX: ffffc90000000000 RBX: ffffffffffffffff RCX: 0000000000000000
[ 0.000000] RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000000000000000
[ 0.000000] RBP: ffffffff81e03f10 R08: 000000000001ad50 R09: 00000000000001f0
[ 0.000000] R10: ffff89773fa20000 R11: 0000000000000001 R12: ffff89773f99f6c0
[ 0.000000] R13: ffffffff8200e920 R14: ffffffff8201c2e0 R15: ffffffff81e03fa8
[ 0.000000] FS: 0000000000000000(0000) GS:ffff897162c00000(0000) knlGS:0000000000000000
[ 0.000000] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 0.000000] CR2: ffffc90000000004 CR3: 0000000001e0a000 CR4: 0000000000000630
[ 0.000000] Stack:
[ 0.000000] ffffffffffffffff ffff89773f99f6c0 ffffffff8200e920 ffffffff8201c2e0
[ 0.000000] ffffffff81e03f20 ffffffff81f7df00 ffffffff81e03f30 ffffffff81f6ee7a
[ 0.000000] ffffffff81e03f40 ffffffff81f6ee4a ffffffff81e03f80 ffffffff81f63f71
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff81f7df00>] hpet_enable+0x1e/0x20
[ 0.000000] [<ffffffff81f6ee7a>] hpet_time_init+0x9/0x19
[ 0.000000] [<ffffffff81f6ee4a>] x86_late_time_init+0x10/0x17
[ 0.000000] [<ffffffff81f63f71>] start_kernel+0x3d8/0x4aa
[ 0.000000] [<ffffffff81f63120>] ? early_idt_handler_array+0x120/0x120
[ 0.000000] [<ffffffff81f63339>] x86_64_start_reservations+0x2a/0x2c
[ 0.000000] [<ffffffff81f63485>] x86_64_start_kernel+0x14a/0x16d
[ 0.000000] Code: 01 00 00 00 41 5c 5d c3 55 48 8b 3d 63 f4 18 00 be 00 04 00 00 48 89 e5 41 56 41 55 41 54 53 e8 f7 f2 0e ff 48 89 05 d8 f4 18 00 <8b> 48 04 b8 e9 03 00 00 48 8b 15 c9 f4 18 00 8b 52 10 ff c2 75
[ 0.000000] RIP [<ffffffff81f7dc60>] hpet_enable.part.13+0x23/0x2a5
[ 0.000000] RSP <ffffffff81e03ef0>
[ 0.000000] CR2: ffffc90000000004
[ 0.000000] ---[ end trace 404be15fe05aa681 ]---
[ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[ 0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task!