Re: [RFC][Patch v8 0/7] KVM: Guest Free Page Hinting

[Alexander Duyck]

On Mon, Feb 4, 2019 at 1:47 PM Nitesh Narayan Lal <nitesh@xxxxxxxxxx> wrote:
>
> The following patch-set proposes an efficient mechanism for handing freed memory between the guest and the host. It enables the guests with no page cache to rapidly free and reclaims memory to and from the host respectively.
>
> Benefit:
> With this patch-series, in our test-case, executed on a single system and single NUMA node with 15GB memory, we were able to successfully launch atleast 5 guests
> when page hinting was enabled and 3 without it. (Detailed explanation of the test procedure is provided at the bottom).
>
> Changelog in V8:
> In this patch-series, the earlier approach [1] which was used to capture and scan the pages freed by the guest has been changed. The new approach is briefly described below:
>
> The patch-set still leverages the existing arch_free_page() to add this functionality. It maintains a per CPU array which is used to store the pages freed by the guest. The maximum number of entries which it can hold is defined by MAX_FGPT_ENTRIES(1000). When the array is completely filled, it is scanned and only the pages which are available in the buddy are stored. This process continues until the array is filled with pages which are part of the buddy free list. After which it wakes up a kernel per-cpu-thread.
> This kernel per-cpu-thread rescans the per-cpu-array for any re-allocation and if the page is not reallocated and present in the buddy, the kernel thread attempts to isolate it from the buddy. If it is successfully isolated, the page is added to another per-cpu array. Once the entire scanning process is complete, all the isolated pages are reported to the host through an existing virtio-balloon driver.
>
> Known Issues:
>         * Fixed array size: The problem with having a fixed/hardcoded array size arises when the size of the guest varies. For example when the guest size increases and it starts making large allocations fixed size limits this solution's ability to capture all the freed pages. This will result in less guest free memory getting reported to the host.
>
> Known code re-work:
>         * Plan to re-use Wei's work, which communicates the poison value to the host.
>         * The nomenclatures used in virtio-balloon needs to be changed so that the code can easily be distinguished from Wei's Free Page Hint code.
>         * Sorting based on zonenum, to avoid repetitive zone locks for the same zone.
>
> Other required work:
>         * Run other benchmarks to evaluate the performance/impact of this approach.
>
> Test case:
> Setup:
> Memory-15837 MB
> Guest Memory Size-5 GB
> Swap-Disabled
> Test Program-Simple program which allocates 4GB memory via malloc, touches it via memset and exits.
> Use case-Number of guests that can be launched completely including the successful execution of the test program.
> Procedure:
> The first guest is launched and once its console is up, the test allocation program is executed with 4 GB memory request (Due to this the guest occupies almost 4-5 GB of memory in the host in a system without page hinting). Once this program exits at that time another guest is launched in the host and the same process is followed. We continue launching the guests until a guest gets killed due to low memory condition in the host.
>
> Result:
> Without Hinting-3 Guests
> With Hinting-5 to 7 Guests(Based on the amount of memory freed/captured).
>
> [1] https://www.spinics.net/lists/kvm/msg170113.html

So I tried reproducing your test and I am not having much luck.
According to the sysctl in the guest  I am seeing
"vm.guest-page-hinting = 1" which is supposed to indicate that the
hinting is enabled in both QEMU and the guest right? I'm just wanting
to verify that this is the case before I start doing any debugging.

I'm assuming you never really ran any multi-threaded tests on a
multi-CPU guest did you? With the patches applied I am seeing
stability issues. If I enable a VM with multiple CPUs and run
something like the page_fault1 test from the will-it-scale suite I am
seeing multiple traces being generated by the guest kernel and it
ultimately just hangs.

I have included the traces below. There end up being 3 specific
issues, a double free that is detected, the RCU stall, and then starts
complaining about a soft lockup.

Thanks.

- Alex

-- This looks like a page complaining about a double add when added to
the LRU --
[   50.479635] list_add double add: new=fffff64480000008,
prev=ffffa000fffd50c0, next=fffff64480000008.
[   50.481066] ------------[ cut here ]------------
[   50.481753] kernel BUG at lib/list_debug.c:31!
[   50.482448] invalid opcode: 0000 [#1] SMP PTI
[   50.483108] CPU: 1 PID: 852 Comm: hinting/1 Not tainted
5.0.0-rc7-next-20190219-baseline+ #50
[   50.486362] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Bochs 01/01/2011
[   50.487881] RIP: 0010:__list_add_valid+0x4b/0x70
[   50.488623] Code: 00 00 c3 48 89 c1 48 c7 c7 d8 70 10 9e 31 c0 e8
4f db c8 ff 0f 0b 48 89 c1 48 89 fe 31 c0 48 c7 c7 88 71 10 9e e8 39
db c8 ff <0f> 0b 48 89 d1 48 c7 c7 30 71 10 9e 48 89 f2 48 89 c6 31 c0
e8 20
[   50.492626] RSP: 0018:ffffb9a8c3b4bdf0 EFLAGS: 00010246
[   50.494189] RAX: 0000000000000058 RBX: ffffa000fffd50c0 RCX: 0000000000000000
[   50.496308] RDX: 0000000000000000 RSI: ffffa000df85e6c8 RDI: ffffa000df85e6c8
[   50.497876] RBP: ffffa000fffd50c0 R08: 0000000000000273 R09: 0000000000000005
[   50.498981] R10: 0000000000000000 R11: ffffb9a8c3b4bb70 R12: fffff64480000008
[   50.500077] R13: fffff64480000008 R14: fffff64480000000 R15: ffffa000fffd5000
[   50.501184] FS:  0000000000000000(0000) GS:ffffa000df840000(0000)
knlGS:0000000000000000
[   50.502432] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   50.503325] CR2: 00007ffff6e47000 CR3: 000000080f76c002 CR4: 0000000000160ee0
[   50.504431] Call Trace:
[   50.505464]  free_one_page+0x2b5/0x470
[   50.506070]  hyperlist_ready+0xa9/0xc0
[   50.506662]  hinting_fn+0x1db/0x3c0
[   50.507220]  smpboot_thread_fn+0x10e/0x160
[   50.507868]  kthread+0xf8/0x130
[   50.508371]  ? sort_range+0x20/0x20
[   50.508934]  ? kthread_bind+0x10/0x10
[   50.509520]  ret_from_fork+0x35/0x40
[   50.510098] Modules linked in: ip6t_rpfilter ip6t_REJECT
nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat
ebtable_broute bridge stp llc ip6table_nat nf_nat_ipv6 ip6table_mangle
ip6table_raw ip6table_security iptable_nat nf_nat_ipv4 nf_nat
nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw
iptable_security ebtable_filter ebtables ip6table_filter ip6_tables
sunrpc sb_edac crct10dif_pclmul crc32_pclmul ghash_clmulni_intel
kvm_intel kvm ppdev irqbypass parport_pc joydev virtio_balloon
pcc_cpufreq i2c_piix4 pcspkr parport xfs libcrc32c cirrus
drm_kms_helper ttm drm e1000 crc32c_intel virtio_blk ata_generic
floppy serio_raw pata_acpi qemu_fw_cfg
[   50.519202] ---[ end trace 141fe2acdf2e3818 ]---
[   50.519935] RIP: 0010:__list_add_valid+0x4b/0x70
[   50.520675] Code: 00 00 c3 48 89 c1 48 c7 c7 d8 70 10 9e 31 c0 e8
4f db c8 ff 0f 0b 48 89 c1 48 89 fe 31 c0 48 c7 c7 88 71 10 9e e8 39
db c8 ff <0f> 0b 48 89 d1 48 c7 c7 30 71 10 9e 48 89 f2 48 89 c6 31 c0
e8 20
[   50.523570] RSP: 0018:ffffb9a8c3b4bdf0 EFLAGS: 00010246
[   50.524399] RAX: 0000000000000058 RBX: ffffa000fffd50c0 RCX: 0000000000000000
[   50.525516] RDX: 0000000000000000 RSI: ffffa000df85e6c8 RDI: ffffa000df85e6c8
[   50.526634] RBP: ffffa000fffd50c0 R08: 0000000000000273 R09: 0000000000000005
[   50.527754] R10: 0000000000000000 R11: ffffb9a8c3b4bb70 R12: fffff64480000008
[   50.528872] R13: fffff64480000008 R14: fffff64480000000 R15: ffffa000fffd5000
[   50.530004] FS:  0000000000000000(0000) GS:ffffa000df840000(0000)
knlGS:0000000000000000
[   50.531276] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   50.532189] CR2: 00007ffff6e47000 CR3: 000000080f76c002 CR4: 0000000000160ee0

-- This appears to be a deadlock on the zone lock --
[  156.436784] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[  156.439195] rcu: 0-...0: (0 ticks this GP)
idle=6ca/1/0x4000000000000000 softirq=10718/10718 fqs=2546
[  156.440810] rcu: 1-...0: (1 GPs behind)
idle=8f2/1/0x4000000000000000 softirq=8233/8235 fqs=2547
[  156.442320] rcu: 2-...0: (0 ticks this GP)
idle=ae2/1/0x4000000000000002 softirq=6779/6779 fqs=2547
[  156.443910] rcu: 3-...0: (0 ticks this GP)
idle=456/1/0x4000000000000000 softirq=1616/1616 fqs=2547
[  156.445454] rcu: (detected by 14, t=60109 jiffies, g=17493, q=31)
[  156.446545] Sending NMI from CPU 14 to CPUs 0:
[  156.448330] NMI backtrace for cpu 0
[  156.448331] CPU: 0 PID: 1308 Comm: page_fault1_pro Tainted: G
D           5.0.0-rc7-next-20190219-baseline+ #50
[  156.448331] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Bochs 01/01/2011
[  156.448332] RIP: 0010:queued_spin_lock_slowpath+0x21/0x1f0
[  156.448332] Code: c0 75 ec c3 90 90 90 90 90 0f 1f 44 00 00 0f 1f
44 00 00 ba 01 00 00 00 8b 07 85 c0 75 0a f0 0f b1 17 85 c0 75 f2 f3
c3 f3 90 <eb> ec 81 fe 00 01 00 00 0f 84 44 01 00 00 81 e6 00 ff ff ff
75 3e
[  156.448333] RSP: 0000:ffffb9a8c3e83c10 EFLAGS: 00000002
[  156.448339] RAX: 0000000000000001 RBX: 0000000000000007 RCX: 0000000000000001
[  156.448340] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffffa000fffd6240
[  156.448340] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000006f36aa
[  156.448341] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000081
[  156.448341] R13: 0000000000100dca R14: 0000000000000000 R15: ffffa000fffd5d00
[  156.448342] FS:  00007ffff7fec440(0000) GS:ffffa000df800000(0000)
knlGS:0000000000000000
[  156.448342] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  156.448342] CR2: 00007fffefe2d000 CR3: 0000000695904004 CR4: 0000000000160ef0
[  156.448343] Call Trace:
[  156.448343]  get_page_from_freelist+0x50f/0x1280
[  156.448343]  ? get_page_from_freelist+0xa44/0x1280
[  156.448344]  __alloc_pages_nodemask+0x141/0x2e0
[  156.448344]  alloc_pages_vma+0x73/0x180
[  156.448344]  __handle_mm_fault+0xd59/0x14e0
[  156.448345]  handle_mm_fault+0xfa/0x210
[  156.448345]  __do_page_fault+0x207/0x4c0
[  156.448345]  do_page_fault+0x32/0x140
[  156.448346]  ? async_page_fault+0x8/0x30
[  156.448346]  async_page_fault+0x1e/0x30
[  156.448346] RIP: 0033:0x401840
[  156.448347] Code: 00 00 45 31 c9 31 ff 41 b8 ff ff ff ff b9 22 00
00 00 ba 03 00 00 00 be 00 00 00 08 e8 d9 f5 ff ff 48 83 f8 ff 74 2b
48 89 c2 <c6> 02 00 48 01 ea 48 83 03 01 48 89 d1 48 29 c1 48 81 f9 ff
ff ff
[  156.448347] RSP: 002b:00007fffffffc0a0 EFLAGS: 00010293
[  156.448348] RAX: 00007fffeee48000 RBX: 00007ffff7ff7000 RCX: 0000000000fe5000
[  156.448348] RDX: 00007fffefe2d000 RSI: 0000000008000000 RDI: 0000000000000000
[  156.448349] RBP: 0000000000001000 R08: ffffffffffffffff R09: 0000000000000000
[  156.448349] R10: 0000000000000022 R11: 0000000000000246 R12: 00007fffffffc240
[  156.448349] R13: 0000000000000000 R14: 0000000000610710 R15: 0000000000000005
[  156.448355] Sending NMI from CPU 14 to CPUs 1:
[  156.489676] NMI backtrace for cpu 1
[  156.489677] CPU: 1 PID: 1309 Comm: page_fault1_pro Tainted: G
D           5.0.0-rc7-next-20190219-baseline+ #50
[  156.489677] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Bochs 01/01/2011
[  156.489678] RIP: 0010:queued_spin_lock_slowpath+0x21/0x1f0
[  156.489678] Code: c0 75 ec c3 90 90 90 90 90 0f 1f 44 00 00 0f 1f
44 00 00 ba 01 00 00 00 8b 07 85 c0 75 0a f0 0f b1 17 85 c0 75 f2 f3
c3 f3 90 <eb> ec 81 fe 00 01 00 00 0f 84 44 01 00 00 81 e6 00 ff ff ff
75 3e
[  156.489679] RSP: 0000:ffffb9a8c3b4bc10 EFLAGS: 00000002
[  156.489679] RAX: 0000000000000001 RBX: 0000000000000007 RCX: 0000000000000001
[  156.489680] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffffa000fffd6240
[  156.489680] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000006f36aa
[  156.489680] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000081
[  156.489681] R13: 0000000000100dca R14: 0000000000000000 R15: ffffa000fffd5d00
[  156.489681] FS:  00007ffff7fec440(0000) GS:ffffa000df840000(0000)
knlGS:0000000000000000
[  156.489682] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  156.489682] CR2: 00007ffff4608000 CR3: 000000081ddf6003 CR4: 0000000000160ee0
[  156.489682] Call Trace:
[  156.489683]  get_page_from_freelist+0x50f/0x1280
[  156.489683]  ? get_page_from_freelist+0xa44/0x1280
[  156.489683]  __alloc_pages_nodemask+0x141/0x2e0
[  156.489683]  alloc_pages_vma+0x73/0x180
[  156.489684]  __handle_mm_fault+0xd59/0x14e0
[  156.489684]  handle_mm_fault+0xfa/0x210
[  156.489684]  __do_page_fault+0x207/0x4c0
[  156.489685]  do_page_fault+0x32/0x140
[  156.489685]  ? async_page_fault+0x8/0x30
[  156.489685]  async_page_fault+0x1e/0x30
[  156.489686] RIP: 0033:0x401840
[  156.489686] Code: 00 00 45 31 c9 31 ff 41 b8 ff ff ff ff b9 22 00
00 00 ba 03 00 00 00 be 00 00 00 08 e8 d9 f5 ff ff 48 83 f8 ff 74 2b
48 89 c2 <c6> 02 00 48 01 ea 48 83 03 01 48 89 d1 48 29 c1 48 81 f9 ff
ff ff
[  156.489687] RSP: 002b:00007fffffffc0a0 EFLAGS: 00010293
[  156.489687] RAX: 00007fffeee48000 RBX: 00007ffff7ff7080 RCX: 00000000057c0000
[  156.489692] RDX: 00007ffff4608000 RSI: 0000000008000000 RDI: 0000000000000000
[  156.489693] RBP: 0000000000001000 R08: ffffffffffffffff R09: 0000000000000000
[  156.489693] R10: 0000000000000022 R11: 0000000000000246 R12: 00007fffffffc240
[  156.489694] R13: 0000000000000000 R14: 000000000060f870 R15: 0000000000000005
[  156.489696] Sending NMI from CPU 14 to CPUs 2:
[  156.530601] NMI backtrace for cpu 2
[  156.530602] CPU: 2 PID: 858 Comm: hinting/2 Tainted: G      D
    5.0.0-rc7-next-20190219-baseline+ #50
[  156.530602] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Bochs 01/01/2011
[  156.530603] RIP: 0010:queued_spin_lock_slowpath+0x21/0x1f0
[  156.530603] Code: c0 75 ec c3 90 90 90 90 90 0f 1f 44 00 00 0f 1f
44 00 00 ba 01 00 00 00 8b 07 85 c0 75 0a f0 0f b1 17 85 c0 75 f2 f3
c3 f3 90 <eb> ec 81 fe 00 01 00 00 0f 84 44 01 00 00 81 e6 00 ff ff ff
75 3e
[  156.530604] RSP: 0018:ffffa000df883e38 EFLAGS: 00000002
[  156.530604] RAX: 0000000000000001 RBX: fffff644a05a0ec8 RCX: dead000000000200
[  156.530605] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffffa000fffd6240
[  156.530605] RBP: ffffa000df8af340 R08: ffffa000da2b2000 R09: 0000000000000100
[  156.530606] R10: 0000000000000004 R11: 0000000000000005 R12: fffff6449fb5fb08
[  156.530606] R13: ffffa000fffd5d00 R14: 0000000000000001 R15: 0000000000000001
[  156.530606] FS:  0000000000000000(0000) GS:ffffa000df880000(0000)
knlGS:0000000000000000
[  156.530607] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  156.530607] CR2: 00007ffff6e47000 CR3: 0000000813b34003 CR4: 0000000000160ee0
[  156.530607] Call Trace:
[  156.530608]  <IRQ>
[  156.530608]  free_pcppages_bulk+0x1af/0x6d0
[  156.530608]  free_unref_page+0x54/0x70
[  156.530608]  tlb_remove_table_rcu+0x23/0x40
[  156.530609]  rcu_core+0x2b0/0x470
[  156.530609]  __do_softirq+0xde/0x2bf
[  156.530609]  irq_exit+0xd5/0xe0
[  156.530610]  smp_apic_timer_interrupt+0x74/0x140
[  156.530610]  apic_timer_interrupt+0xf/0x20
[  156.530610]  </IRQ>
[  156.530611] RIP: 0010:_raw_spin_lock+0x10/0x20
[  156.530611] Code: b8 01 00 00 00 c3 48 8b 3c 24 be 00 02 00 00 e8
f6 cf 77 ff 31 c0 c3 0f 1f 00 0f 1f 44 00 00 31 c0 ba 01 00 00 00 f0
0f b1 17 <0f> 94 c2 84 d2 74 02 f3 c3 89 c6 e9 d0 e8 7c ff 0f 1f 44 00
00 65
[  156.530612] RSP: 0018:ffffb9a8c3bf3df0 EFLAGS: 00000246 ORIG_RAX:
ffffffffffffff13
[  156.530612] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
[  156.530613] RDX: 0000000000000001 RSI: fffff6449fd4aec0 RDI: ffffa000fffd6240
[  156.530613] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000002
[  156.530613] R10: 0000000000000000 R11: 0000000000003bf3 R12: 00000000007f52bb
[  156.530614] R13: 00000000007ecca4 R14: fffff6449fd4aec0 R15: ffffa000fffd5d00
[  156.530614]  free_one_page+0x32/0x470
[  156.530614]  ? __switch_to_asm+0x40/0x70
[  156.530615]  hyperlist_ready+0xa9/0xc0
[  156.530615]  hinting_fn+0x1db/0x3c0
[  156.530615]  smpboot_thread_fn+0x10e/0x160
[  156.530616]  kthread+0xf8/0x130
[  156.530616]  ? sort_range+0x20/0x20
[  156.530616]  ? kthread_bind+0x10/0x10
[  156.530616]  ret_from_fork+0x35/0x40
[  156.530619] Sending NMI from CPU 14 to CPUs 3:
[  156.577112] NMI backtrace for cpu 3
[  156.577113] CPU: 3 PID: 1311 Comm: page_fault1_pro Tainted: G
D           5.0.0-rc7-next-20190219-baseline+ #50
[  156.577113] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Bochs 01/01/2011
[  156.577114] RIP: 0010:queued_spin_lock_slowpath+0x21/0x1f0
[  156.577114] Code: c0 75 ec c3 90 90 90 90 90 0f 1f 44 00 00 0f 1f
44 00 00 ba 01 00 00 00 8b 07 85 c0 75 0a f0 0f b1 17 85 c0 75 f2 f3
c3 f3 90 <eb> ec 81 fe 00 01 00 00 0f 84 44 01 00 00 81 e6 00 ff ff ff
75 3e
[  156.577115] RSP: 0000:ffffb9a8c407fc10 EFLAGS: 00000002
[  156.577115] RAX: 0000000000000001 RBX: 0000000000000007 RCX: 0000000000000001
[  156.577116] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffffa000fffd6240
[  156.577116] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000006f36aa
[  156.577121] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000081
[  156.577122] R13: 0000000000100dca R14: 0000000000000000 R15: ffffa000fffd5d00
[  156.577122] FS:  00007ffff7fec440(0000) GS:ffffa000df8c0000(0000)
knlGS:0000000000000000
[  156.577122] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  156.577123] CR2: 00007ffff398a000 CR3: 000000081aa00003 CR4: 0000000000160ee0
[  156.577123] Call Trace:
[  156.577123]  get_page_from_freelist+0x50f/0x1280
[  156.577124]  ? get_page_from_freelist+0xa44/0x1280
[  156.577124]  ? try_charge+0x637/0x860
[  156.577124]  __alloc_pages_nodemask+0x141/0x2e0
[  156.577125]  alloc_pages_vma+0x73/0x180
[  156.577125]  __handle_mm_fault+0xd59/0x14e0
[  156.577125]  handle_mm_fault+0xfa/0x210
[  156.577126]  __do_page_fault+0x207/0x4c0
[  156.577126]  do_page_fault+0x32/0x140
[  156.577126]  ? async_page_fault+0x8/0x30
[  156.577127]  async_page_fault+0x1e/0x30
[  156.577127] RIP: 0033:0x401840
[  156.577128] Code: 00 00 45 31 c9 31 ff 41 b8 ff ff ff ff b9 22 00
00 00 ba 03 00 00 00 be 00 00 00 08 e8 d9 f5 ff ff 48 83 f8 ff 74 2b
48 89 c2 <c6> 02 00 48 01 ea 48 83 03 01 48 89 d1 48 29 c1 48 81 f9 ff
ff ff
[  156.577128] RSP: 002b:00007fffffffc0a0 EFLAGS: 00010293
[  156.577129] RAX: 00007fffeee48000 RBX: 00007ffff7ff7180 RCX: 0000000004b42000
[  156.577129] RDX: 00007ffff398a000 RSI: 0000000008000000 RDI: 0000000000000000
[  156.577130] RBP: 0000000000001000 R08: ffffffffffffffff R09: 0000000000000000
[  156.577130] R10: 0000000000000022 R11: 0000000000000246 R12: 00007fffffffc240
[  156.577130] R13: 0000000000000000 R14: 000000000060db00 R15: 0000000000000005

-- After the above two it starts spitting this one out every 10 - 30
seconds or so --
[  183.788386] watchdog: BUG: soft lockup - CPU#14 stuck for 23s!
[kworker/14:1:121]
[  183.790003] Modules linked in: ip6t_rpfilter ip6t_REJECT
nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat
ebtable_broute bridge stp llc ip6table_nat nf_nat_ipv6 ip6table_mangle
ip6table_raw ip6table_security iptable_nat nf_nat_ipv4 nf_nat
nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw
iptable_security ebtable_filter ebtables ip6table_filter ip6_tables
sunrpc sb_edac crct10dif_pclmul crc32_pclmul ghash_clmulni_intel
kvm_intel kvm ppdev irqbypass parport_pc joydev virtio_balloon
pcc_cpufreq i2c_piix4 pcspkr parport xfs libcrc32c cirrus
drm_kms_helper ttm drm e1000 crc32c_intel virtio_blk ata_generic
floppy serio_raw pata_acpi qemu_fw_cfg
[  183.799984] CPU: 14 PID: 121 Comm: kworker/14:1 Tainted: G      D
        5.0.0-rc7-next-20190219-baseline+ #50
[  183.801674] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Bochs 01/01/2011
[  183.803078] Workqueue: events netstamp_clear
[  183.803873] RIP: 0010:smp_call_function_many+0x206/0x260
[  183.804847] Code: e8 0f 97 7c 00 3b 05 bd d1 1e 01 0f 83 7c fe ff
ff 48 63 d0 48 8b 4d 00 48 03 0c d5 80 28 18 9e 8b 51 18 83 e2 01 74
0a f3 90 <8b> 51 18 83 e2 01 75 f6 eb c7 0f b6 4c 24 0c 48 83 c4 10 89
ef 5b
[  183.808273] RSP: 0018:ffffb9a8c35a3d38 EFLAGS: 00000202 ORIG_RAX:
ffffffffffffff13
[  183.809662] RAX: 0000000000000000 RBX: ffffa000dfba9d88 RCX: ffffa000df8301c0
[  183.810971] RDX: 0000000000000001 RSI: 0000000000000100 RDI: ffffa000dfba9d88
[  183.812268] RBP: ffffa000dfba9d80 R08: 0000000000000000 R09: 0000000000003fff
[  183.813582] R10: 0000000000000000 R11: 000000000000000f R12: ffffffff9d02f690
[  183.814884] R13: 0000000000000000 R14: ffffa000dfba9da8 R15: 0000000000000100
[  183.816195] FS:  0000000000000000(0000) GS:ffffa000dfb80000(0000)
knlGS:0000000000000000
[  183.817673] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  183.818729] CR2: 00007ffff704b080 CR3: 0000000814c48001 CR4: 0000000000160ee0
[  183.820038] Call Trace:
[  183.820510]  ? netif_receive_skb_list+0x68/0x4a0
[  183.821367]  ? poke_int3_handler+0x40/0x40
[  183.822126]  ? netif_receive_skb_list+0x69/0x4a0
[  183.822975]  on_each_cpu+0x28/0x60
[  183.823611]  ? netif_receive_skb_list+0x68/0x4a0
[  183.824467]  text_poke_bp+0x68/0xe0
[  183.825126]  ? netif_receive_skb_list+0x68/0x4a0
[  183.825983]  __jump_label_transform+0x101/0x140
[  183.826829]  arch_jump_label_transform+0x26/0x40
[  183.827687]  __jump_label_update+0x56/0xc0
[  183.828456]  static_key_enable_cpuslocked+0x57/0x80
[  183.829358]  static_key_enable+0x16/0x20
[  183.830085]  process_one_work+0x16c/0x380
[  183.830831]  worker_thread+0x49/0x3e0
[  183.831516]  kthread+0xf8/0x130
[  183.832106]  ? rescuer_thread+0x340/0x340
[  183.832848]  ? kthread_bind+0x10/0x10
[  183.833532]  ret_from_fork+0x35/0x40