I was about to give up trying to recreate this.  Everything was updated as a hour or so earlier today.  Meaning in the last 5 days, whatever updates were prompted had been applied as and when they showed up and I got around to doing the updates.  System had not been restarted since the time below.  It had been up for over 5 days now since the last time it froze.

00:28:01 up 5 days,  5:53,  1 user,  load average: 2.58, 0.96, 0.62

$ uname -a
Linux roke 4.15.0-10-generic #11-Ubuntu SMP Tue Feb 13 18:23:35 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu Bionic Beaver (development branch)
Release:	18.04
Codename:	bionic

But then this happened.  This is the first time I have seen any logs that could be useful ...

Mar 10 00:32:01 roke kernel: [453428.641614] [drm:drm_atomic_helper_wait_for_dependencies [drm_kms_helper]] *ERROR* [CRTC:43:crtc-0] flip_done timed out
Mar 10 00:33:51 roke kernel: [453478.603354] INFO: rcu_sched detected stalls on CPUs/tasks:
Mar 10 00:33:51 roke kernel: [453478.603364]    8-...!: (1 GPs behind) idle=b6c/0/0 softirq=4280452/4280453 fqs=0 
Mar 10 00:33:51 roke kernel: [453478.603368]    9-...!: (11 GPs behind) idle=3bc/0/0 softirq=962607/962607 fqs=0 
Mar 10 00:33:51 roke kernel: [453478.603371]    10-...!: (0 ticks this GP) idle=a2c/0/0 softirq=3620248/3620248 fqs=0 
Mar 10 00:33:51 roke kernel: [453478.603375]    11-...!: (40 GPs behind) idle=cd8/0/0 softirq=3434620/3434620 fqs=0 
Mar 10 00:33:51 roke kernel: [453478.603378]    12-...!: (1 GPs behind) idle=ac8/0/0 softirq=5369219/5369220 fqs=0 
Mar 10 00:33:51 roke kernel: [453478.603381]    13-...!: (39 GPs behind) idle=528/0/0 softirq=10045630/10045630 fqs=0 
Mar 10 00:33:51 roke kernel: [453478.603383]    (detected by 4, t=15002 jiffies, g=8374930, c=8374929, q=535)
Mar 10 00:33:51 roke kernel: [453478.603388] Sending NMI from CPU 4 to CPUs 8:
Mar 10 00:33:51 roke kernel: [453488.529115] Sending NMI from CPU 4 to CPUs 9:
Mar 10 00:33:51 roke kernel: [453498.453348] Sending NMI from CPU 4 to CPUs 10:
Mar 10 00:33:51 roke kernel: [453508.377571] Sending NMI from CPU 4 to CPUs 11:
Mar 10 00:33:51 roke kernel: [453518.301796] Sending NMI from CPU 4 to CPUs 12:
Mar 10 00:33:51 roke kernel: [453528.226048] Sending NMI from CPU 4 to CPUs 13:
Mar 10 00:33:51 roke kernel: [453538.150337] rcu_sched kthread starved for 26177 jiffies! g8374930 c8374929 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=10
Mar 10 00:33:51 roke kernel: [453538.150340] rcu_sched       I    0     8      2 0x80000000
Mar 10 00:33:51 roke kernel: [453538.150344] Call Trace:
Mar 10 00:33:51 roke kernel: [453538.150351]  __schedule+0x297/0x8a0
Mar 10 00:33:51 roke kernel: [453538.150354]  schedule+0x2c/0x80
Mar 10 00:33:51 roke kernel: [453538.150356]  schedule_timeout+0x15d/0x350
Mar 10 00:33:51 roke kernel: [453538.150360]  ? __next_timer_interrupt+0xe0/0xe0
Mar 10 00:33:51 roke kernel: [453538.150364]  rcu_gp_kthread+0x53a/0x960
Mar 10 00:33:51 roke kernel: [453538.150367]  kthread+0x121/0x140
Mar 10 00:33:51 roke kernel: [453538.150370]  ? rcu_note_context_switch+0x150/0x150
Mar 10 00:33:51 roke kernel: [453538.150371]  ? kthread_create_worker_on_cpu+0x70/0x70
Mar 10 00:33:51 roke kernel: [453538.150373]  ret_from_fork+0x22/0x40
Mar 10 00:34:06 roke kernel: [453553.171401] sysrq: SysRq : Emergency Remount R/O