autopkgtest never completes

The autopkgtest for liburing version 2.2-1 never completed (after running for multiple days) on architectures other than armhf. Looking at the nova console-log of a system on which the test quit we can see the following:

[ 124.252878] watchdog: BUG: soft lockup - CPU#0 stuck for 26s! [iou-wrk-20780:20781]
[ 152.252347] watchdog: BUG: soft lockup - CPU#0 stuck for 52s! [iou-wrk-20780:20781]
[ 157.144266] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 157.155080] rcu: All QSes seen, last rcu_sched kthread activity 15002 (4294931526-4294916524), jiffies_till_next_fqs=1, root ->qsmask 0x0
[ 157.159348] rcu: rcu_sched kthread starved for 15002 jiffies! g54173 f0x2 RCU_GP_WAIT_FQS(5) ->state=
0x0 ->cpu=0
[ 157.162870] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
[ 157.165941] rcu: RCU grace-period kthread stack dump:
[ 157.167718] rcu: Stack dump where RCU GP kthread last ran:
[ 184.251805] watchdog: BUG: soft lockup - CPU#0 stuck for 82s! [iou-wrk-20780:20781]
[ 212.251321] watchdog: BUG: soft lockup - CPU#0 stuck for 108s! [iou-wrk-20780:20781]
[ 240.250857] watchdog: BUG: soft lockup - CPU#0 stuck for 134s! [iou-wrk-20780:20781]
[ 268.250374] watchdog: BUG: soft lockup - CPU#0 stuck for 160s! [iou-wrk-20780:20781]
[ 296.249901] watchdog: BUG: soft lockup - CPU#0 stuck for 186s! [iou-wrk-20780:20781]
[ 324.249428] watchdog: BUG: soft lockup - CPU#0 stuck for 212s! [iou-wrk-20780:20781]
[ 337.161224] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 337.181627] rcu: All QSes seen, last rcu_sched kthread activity 60007 (4294976531-4294916524), jiffie
s_till_next_fqs=1, root ->qsmask 0x0
[ 337.186084] rcu: rcu_sched kthread starved for 60007 jiffies! g54173 f0x2 RCU_GP_WAIT_FQS(5) ->state=
0x0 ->cpu=0
[ 337.189767] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
[ 337.193001] rcu: RCU grace-period kthread stack dump:
[ 337.194932] rcu: Stack dump where RCU GP kthread last ran:
[ 364.248759] watchdog: BUG: soft lockup - CPU#0 stuck for 250s! [iou-wrk-20780:20781]
[ 392.248279] watchdog: BUG: soft lockup - CPU#0 stuck for 276s! [iou-wrk-20780:20781]
[ 420.247807] watchdog: BUG: soft lockup - CPU#0 stuck for 302s! [iou-wrk-20780:20781]
[ 448.247334] watchdog: BUG: soft lockup - CPU#0 stuck for 328s! [iou-wrk-20780:20781]
[ 476.246860] watchdog: BUG: soft lockup - CPU#0 stuck for 354s! [iou-wrk-20780:20781]
[ 504.246388] watchdog: BUG: soft lockup - CPU#0 stuck for 380s! [iou-wrk-20780:20781]
[ 517.178184] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 517.189702] rcu: All QSes seen, last rcu_sched kthread activity 105012 (4295021536-4294916524), jiffi
es_till_next_fqs=1, root ->qsmask 0x0
[ 517.194281] rcu: rcu_sched kthread starved for 105012 jiffies! g54173 f0x2 RCU_GP_WAIT_FQS(5) ->state
=0x0 ->cpu=0
[ 517.198006] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
[ 517.201259] rcu: RCU grace-period kthread stack dump:
[ 517.203255] rcu: Stack dump where RCU GP kthread last ran:
[ 544.245712] watchdog: BUG: soft lockup - CPU#0 stuck for 417s! [iou-wrk-20780:20781]
[ 572.245238] watchdog: BUG: soft lockup - CPU#0 stuck for 443s! [iou-wrk-20780:20781]
[ 600.244765] watchdog: BUG: soft lockup - CPU#0 stuck for 470s! [iou-wrk-20780:20781]
[ 628.244292] watchdog: BUG: soft lockup - CPU#0 stuck for 496s! [iou-wrk-20780:20781]
[ 656.243818] watchdog: BUG: soft lockup - CPU#0 stuck for 522s! [iou-wrk-20780:20781]
[ 684.243351] watchdog: BUG: soft lockup - CPU#0 stuck for 548s! [iou-wrk-20780:20781]
[ 697.195143] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 697.197433] rcu: All QSes seen, last rcu_sched kthread activity 150017 (4295066541-4294916524), jiffies_till_next_fqs=1, root ->qsmask 0x0
[ 697.201942] rcu: rcu_sched kthread starved for 150017 jiffies! g54173 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
[ 697.205683] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
[ 697.208946] rcu: RCU grace-period kthread stack dump:
[ 697.210867] rcu: Stack dump where RCU GP kthread last ran:
[ 724.242670] watchdog: BUG: soft lockup - CPU#0 stuck for 585s! [iou-wrk-20780:20781]
[ 752.242198] watchdog: BUG: soft lockup - CPU#0 stuck for 611s! [iou-wrk-20780:20781]
[ 780.241724] watchdog: BUG: soft lockup - CPU#0 stuck for 637s! [iou-wrk-20780:20781]
[ 808.241251] watchdog: BUG: soft lockup - CPU#0 stuck for 663s! [iou-wrk-20780:20781]
[ 836.240777] watchdog: BUG: soft lockup - CPU#0 stuck for 689s! [iou-wrk-20780:20781]
[ 864.240304] watchdog: BUG: soft lockup - CPU#0 stuck for 715s! [iou-wrk-20780:20781]
[ 877.212093] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 877.231984] rcu: All QSes seen, last rcu_sched kthread activity 195022 (4295111546-4294916524), jiffies_till_next_fqs=1, root ->qsmask 0x0
[ 877.236384] rcu: rcu_sched kthread starved for 195022 jiffies! g54173 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
[ 877.240073] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
[ 877.243246] rcu: RCU grace-period kthread stack dump:
[ 877.245144] rcu: Stack dump where RCU GP kthread last ran:
[ 904.239629] watchdog: BUG: soft lockup - CPU#0 stuck for 753s! [iou-wrk-20780:20781]
[ 932.239155] watchdog: BUG: soft lockup - CPU#0 stuck for 779s! [iou-wrk-20780:20781]
[ 960.238696] watchdog: BUG: soft lockup - CPU#0 stuck for 805s! [iou-wrk-20780:20781]
[ 988.238213] watchdog: BUG: soft lockup - CPU#0 stuck for 831s! [iou-wrk-20780:20781]
[ 1016.237736] watchdog: BUG: soft lockup - CPU#0 stuck for 857s! [iou-wrk-20780:20781]
[ 1044.237265] watchdog: BUG: soft lockup - CPU#0 stuck for 883s! [iou-wrk-20780:20781]
[ 1057.229052] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 1057.239921] rcu: All QSes seen, last rcu_sched kthread activity 240027 (4295156551-4294916524), jiffies_till_next_fqs=1, root ->qsmask 0x0
[ 1057.244147] rcu: rcu_sched kthread starved for 240027 jiffies! g54173 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
[ 1057.247614] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
[ 1057.250553] rcu: RCU grace-period kthread stack dump:
[ 1057.252334] rcu: Stack dump where RCU GP kthread last ran:
[ 1084.236586] watchdog: BUG: soft lockup - CPU#0 stuck for 920s! [iou-wrk-20780:20781]
[ 1112.236116] watchdog: BUG: soft lockup - CPU#0 stuck for 946s! [iou-wrk-20780:20781]
[ 1140.235643] watchdog: BUG: soft lockup - CPU#0 stuck for 972s! [iou-wrk-20780:20781]
[ 1168.235168] watchdog: BUG: soft lockup - CPU#0 stuck for 999s! [iou-wrk-20780:20781]
[ 1196.234696] watchdog: BUG: soft lockup - CPU#0 stuck for 1025s! [iou-wrk-20780:20781]
[ 1224.234222] watchdog: BUG: soft lockup - CPU#0 stuck for 1051s! [iou-wrk-20780:20781]
[ 1237.246018] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 1237.248209] rcu: All QSes seen, last rcu_sched kthread activity 285032 (4295201556-4294916524), jiffies_till_next_fqs=1, root ->qsmask 0x0
[ 1237.252563] rcu: rcu_sched kthread starved for 285032 jiffies! g54173 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
[ 1237.256170] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
[ 1237.259309] rcu: RCU grace-period kthread stack dump:
[ 1237.261174] rcu: Stack dump where RCU GP kthread last ran:
[ 1264.233546] watchdog: BUG: soft lockup - CPU#0 stuck for 1088s! [iou-wrk-20780:20781] [ 1292.233073] watchdog: BUG: soft lockup - CPU#0 stuck for 1114s! [iou-wrk-20780:20781]