gh/vmtests: panic on RCU stalls

We have been hitting an issue, where the test will continuously print
RCU stalls. Set an option to just panic if that happens

[ 1109.837053] rcu: 	1-...!: (20984 ticks this GP) idle=a4a/1/0x4000000000000002 softirq=46388/46388 fqs=1
[ 1109.837053] 	(t=21001 jiffies g=140697 q=9)
[ 1109.837053] rcu: rcu_sched kthread starved for 20995 jiffies! g140697 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
[ 1109.837053] rcu: RCU grace-period kthread stack dump:
[ 1109.837053] rcu_sched       R  running task    14904    11      2 0x90004000
[ 1109.837053] Call Trace:
[ 1109.837053]  __schedule+0x237/0x610
[ 1109.837053]  ? __mod_timer+0x19d/0x3c0
[ 1109.837053]  schedule+0x34/0xa0
[ 1109.837053]  schedule_timeout+0x84/0x150
[ 1109.837053]  ? __next_timer_interrupt+0xc0/0xc0
[ 1109.837053]  rcu_gp_kthread+0x4f4/0xd50
[ 1109.837053]  ? kfree_call_rcu+0x10/0x10
[ 1109.837053]  kthread+0x112/0x130
[ 1109.837053]  ? __kthread_bind_mask+0x60/0x60
[ 1109.837053]  ret_from_fork+0x35/0x40
[ 1109.837053] NMI backtrace for cpu 1
[ 1109.837053] CPU: 1 PID: 533 Comm: pkg.sensors.tra Not tainted 5.4.206 #1
[ 1109.837053] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 1109.837053] Call Trace:
[ 1109.837053]  <IRQ>
[ 1109.837053]  dump_stack+0x50/0x63
[ 1109.837053]  nmi_cpu_backtrace.cold+0x14/0x53
[ 1109.837053]  ? lapic_can_unplug_cpu+0x70/0x70
[ 1109.837053]  nmi_trigger_cpumask_backtrace+0x7c/0x90
[ 1109.837053]  rcu_dump_cpu_stacks+0x7c/0xaa
[ 1109.837053]  rcu_sched_clock_irq.cold+0x1b3/0x39e
[ 1109.837053]  update_process_times+0x56/0x90
[ 1109.837053]  tick_sched_handle+0x2f/0x40
[ 1109.837053]  tick_sched_timer+0x4c/0xb0
[ 1109.837053]  ? can_stop_idle_tick+0x90/0x90
[ 1109.837053]  __hrtimer_run_queues+0x123/0x2a0
[ 1109.837053]  hrtimer_interrupt+0x10b/0x2c0
[ 1109.837053]  smp_apic_timer_interrupt+0x61/0x130
[ 1109.837053]  apic_timer_interrupt+0xf/0x20
[ 1109.837053]  </IRQ>
[ 1109.837053] RIP: 0010:syscall_trace_enter+0x1f1/0x290
[ 1109.837053] Code: 01 00 48 c7 80 88 07 00 00 00 00 00 00 48 8b 10 83 e2 04 74 af f6 80 c9 06 00 00 01 74 a6 48 c7 c0 ff ff ff ff e9 25 ff ff ff <e9> 40 00 00 00 e9 ec fe ff ff 4c 8b 4b 58 48 8b 73 28 49 89 d0 4c
[ 1109.837053] RSP: 0018:ffffbb0f40247ec8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
[ 1109.837053] RAX: 0000000010000000 RBX: ffffbb0f40247f58 RCX: 0000000000000000
[ 1109.837053] RDX: 0000000000000000 RSI: ffffbb0f40247f58 RDI: 00000000000000e4
[ 1109.837053] RBP: 00000000c000003e R08: 0000000000000000 R09: 0000000000000000
[ 1109.837053] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 1109.837053] R13: 00000000000000e4 R14: 0000000010000000 R15: 0000000000000000
[ 1109.837053]  ? _copy_to_user+0x28/0x30
[ 1109.837053]  ? put_timespec64+0x35/0x60
[ 1109.837053]  do_syscall_64+0xc8/0x110
[ 1109.837053]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1109.837053] RIP: 0033:0x7ffd2f7bb7ff

Signed-off-by: Kornilios Kourtis <[email protected]>

.github/workflows/vmtests.yml

@@ -69,6 +69,10 @@ jobs:
       run: |
         sudo chmod go+rX -R /boot/
 
+    - name: set panic on RCU stall
+      run: |
+        sudo sh -c 'echo 1 > /proc/sys/kernel/panic_on_rcu_stall'
+
     - name: download build data
       uses: actions/download-artifact@v3
       with: