POWER9 with Linux 4.19.13+:

watchdog: CPU 63 detected hard LOCKUP on other CPUs 30
watchdog: CPU 63 TB:122015771914635, last SMP heartbeat TB:122008037684358 (15105ms ago)
watchdog: CPU 30 Hard LOCKUP
watchdog: CPU 30 TB:122015771998091, last heartbeat TB:122007775369048 (15618ms ago)
Modules linked in: ccm 8021q garp mrp stp llc arc4 binfmt_misc snd_usb_audio snd_hwdep snd_usbmidi_lib ath9k_htc snd_rawmidi snd_seq_device ath9k_common snd_pcm ath9k_hw snd_timer mac_hid snd soundcore usbkbd ath usbmouse vmx_crypto ahci libahci at24 ibmpowernv uio_pdrv_genirq uio dm_crypt algif_skcipher af_alg rt2800usb rt2x00usb rt2800lib rt2x00lib mac80211 cfg80211 hid_apple xhci_pci xhci_hcd ehci_pci ehci_hcd ohci_pci ohci_hcd usbhid usbcore usb_common hid_generic hid amdgpu hwmon chash i2c_algo_bit gpu_sched ttm drm_kms_helper cfbfillrect syscopyarea cfbimgblt sysfillrect sysimgblt fb_sys_fops cfbcopyarea drm drm_panel_orientation_quirks
CPU: 30 PID: 0 Comm: swapper/30 Not tainted 4.19.13+ #71
NIP:  c0000000000a6484 LR: c0000000000a6484 CTR: c00000000003cc70
REGS: c0000007fa6abc10 TRAP: 0100   Not tainted  (4.19.13+)
MSR:  9000000000001033 <SF,HV,ME,IR,DR,RI,LE>  CR: 24004282  XER: 20040000
CFAR: c0000007fa6abd70 IRQMASK: c0000007fa6abdc0 
GPR00: c0000000000a6484 c0000007fa6abd70 c000000003e01300 c0000007fa6abc10 
GPR04: b000000000001033 c0000000000a5ea0 0000000024004284 0000000000000004 
GPR08: 004040000182f012 c000000000bf0f20 00000000000000ff c0000007ffc42080 
GPR12: 9000000000121001 c0000007fffdd400 c0000007fa6abf90 0000000000000000 
GPR16: 0000000000000000 c00000000004a810 c00000000004a7e0 c0000007ffcb51c0 
GPR20: 0000000000000100 c000000003e27824 000000000000001e 0000000000000000 
GPR24: 0000000000000006 0000000000000006 0000000000000000 0000000000000006 
GPR28: c000000003d51e10 c0000007ffcd6248 c000000003d52068 0000000000000006 
NIP [c0000000000a6484] power9_idle_type+0x24/0x40
LR [c0000000000a6484] power9_idle_type+0x24/0x40
Call Trace:
[c0000007fa6abd70] [c0000000000a6484] power9_idle_type+0x24/0x40 (unreliable)
[c0000007fa6abd90] [c0000000009a5520] stop_loop+0x40/0x60
[c0000007fa6abdc0] [c0000000009a1734] cpuidle_enter_state+0xa4/0x4c0
[c0000007fa6abe30] [c0000000001592cc] call_cpuidle+0x4c/0x90
[c0000007fa6abe50] [c0000000001598fc] do_idle+0x32c/0x3e0
[c0000007fa6abec0] [c000000000159be8] cpu_startup_entry+0x38/0x50
[c0000007fa6abef0] [c00000000004cdc8] start_secondary+0x4f8/0x550
[c0000007fa6abf90] [c00000000000ab70] start_secondary_prolog+0x10/0x14
Instruction dump:
ebe1fff8 7c0803a6 4e800020 3c4c03d6 3842aea0 7c0802a6 60000000 7c0802a6 
f8010010 f821ffe1 4bfff9ad 4bf736e9 <60000000> 38210020 e8010010 7c0803a6 
watchdog: CPU 30 became unstuck TB:122018655929803
CPU: 30 PID: 0 Comm: swapper/30 Not tainted 4.19.13+ #71
NIP:  c00000000000a81c LR: c000000000019a04 CTR: 00007fffa48f8be0
REGS: c0000007fa6abb20 TRAP: 0901   Not tainted  (4.19.13+)
MSR:  9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 28004284  XER: 00000000
CFAR: 00007fff9a4c43d0 IRQMASK: 0 
GPR00: c0000000009a1780 c0000007fa6abda0 c000000003e01300 0000000000000900 
GPR04: b000000000001033 c0000000000a5ea0 0000000028004284 0000000000000008 
GPR08: c0000007fffdd400 0000000000000000 0000000000000000 00007fff58fe249e 
GPR12: 00007fffa48f8be0 00007fffa4dcc6f0 
NIP [c00000000000a81c] replay_interrupt_return+0x0/0x4
LR [c000000000019a04] arch_local_irq_restore.part.4+0x54/0x70
Call Trace:
[c0000007fa6abda0] [c0000007fa6abe50] 0xc0000007fa6abe50 (unreliable)
[c0000007fa6abdc0] [c0000000009a1780] cpuidle_enter_state+0xf0/0x4c0
[c0000007fa6abe30] [c0000000001592cc] call_cpuidle+0x4c/0x90
[c0000007fa6abe50] [c0000000001598fc] do_idle+0x32c/0x3e0
[c0000007fa6abec0] [c000000000159bec] cpu_startup_entry+0x3c/0x50
[c0000007fa6abef0] [c00000000004cdc8] start_secondary+0x4f8/0x550
[c0000007fa6abf90] [c00000000000ab70] start_secondary_prolog+0x10/0x14
Instruction dump:
7d200026 618c8000 2c030900 4182e7f8 2c030500 4182f2e0 2c030f00 4182f3f8 
2c030a00 4182ff9c 2c030e60 4182f088 <4e800020> 7c781b78 48000365 4800037d