Comment 9 for bug 1864063

On a arm64 node we had some more useful console logs:

https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-bionic/bionic/arm64/l/linux/20200223_153549_99119@/log.gz

[ 7400.666431] rcu_sched kthread starved for 240027 jiffies! g460241 c460240 f0x2 RCU_GP_WAIT_FQS(3)
 ->state=0x0 ->cpu=1
[ 7426.939201] watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [stress-ng-vm-se:29260]
[ 7427.941599] watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [stress-ng-vm-se:28674]
[ 7580.664232] INFO: rcu_sched self-detected stall on CPU
[ 7580.666689] 3-...!: (284881 ticks this GP) idle=cfa/140000000000001/0 softirq=1720701/1720703 fq
s=0
[ 7580.671124] (t=285031 jiffies g=460241 c=460240 q=979)
[ 7580.672223] INFO: rcu_sched detected stalls on CPUs/tasks:
[ 7580.673660] rcu_sched kthread starved for 285032 jiffies! g460241 c460240 f0x2 RCU_GP_WAIT_FQS(3)
 ->state=0x0 ->cpu=1
[ 7580.675893] 3-...!: (284881 ticks this GP) idle=cfa/140000000000001/0 softirq=1720701/1720703 fqs=0
[ 7580.685152]
[ 7580.686074] rcu_sched kthread starved for 285035 jiffies! g460241 c460240 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1
[ 7606.937596] watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [stress-ng-vm-se:29260]
[ 7607.947991] watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [stress-ng-vm-se:29259]