Got the following kernel BUG today.

Have had previous "hangs" but this is the first one I caught since connecting a serial console to track this down.

[100526.938347] kernel BUG at mm/page_alloc.c:2019!
[100526.942980] invalid opcode: 0000 [#1] SMP PTI
[100526.947420] Modules linked in: hidp rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache rfcomm fuse xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_conntrack tun devlink ebtable_filter ebtables ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc bnep it87 hwmon_vid btrfs xor zstd_compress raid6_pq libcrc32c zstd_decompress xxhash intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm gpio_ich iTCO_wdt iTCO_vendor_support ppdev irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel intel_cstate intel_uncore intel_rapl_perf btusb btrtl btbcm btintel bluetooth snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic snd_hda_intel ecdh_generic rfkill snd_hda_codec i2c_i801 snd_hda_core snd_hwdep
[100527.018194]  snd_seq snd_seq_device snd_pcm lpc_ich snd_timer mei_me snd mei soundcore shpchp parport_pc parport nfsd nfs_acl lockd grace auth_rpcgss sunrpc binfmt_misc i915 crc32c_intel serio_raw i2c_algo_bit drm_kms_helper r8169 sata_via mii drm video
[100527.040677] CPU: 1 PID: 11491 Comm: kworker/u4:2 Not tainted 4.17.6-200.fc28.x86_64 #1
[100527.048666] Hardware name: Gigabyte Technology Co., Ltd. H81M-S2PV/H81M-S2PV, BIOS F8 06/19/2014
[100527.057528] Workqueue: writeback wb_workfn (flush-253:3)
[100527.062924] RIP: 0010:move_freepages_block+0x167/0x2e0
[100527.068140] RSP: 0018:ffffa66d0f5b3488 EFLAGS: 00010083
[100527.073443] RAX: ffff9aa81f1d5680 RBX: 0000000000100000 RCX: ffff9aa81f1d5000
[100527.080654] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
[100527.087864] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff9aa81f1d5888
[100527.095075] R10: ffffffff87e28824 R11: ffff9aa81f1d1000 R12: ffffe798c31c5800
[100527.102286] R13: ffff9aa81f1d5680 R14: ffffa66d0f5b34ec R15: ffffe798c31c0000
[100527.109497] FS:  0000000000000000(0000) GS:ffff9aa81ef00000(0000) knlGS:0000000000000000
[100527.117661] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[100527.123485] CR2: 00001945e61d9008 CR3: 000000033420a004 CR4: 00000000000606e0
[100527.130696] Call Trace:
[100527.133230]  steal_suitable_fallback+0x119/0x1b0
[100527.137933]  get_page_from_freelist+0xfb8/0x16a0
[100527.142631]  __alloc_pages_nodemask+0x11e/0x2b0
[100527.147243]  new_slab+0x293/0x740
[100527.150648]  ___slab_alloc+0x3b4/0x550
[100527.154479]  ? mempool_alloc+0x70/0x1a0
[100527.158404]  ? mempool_alloc+0x70/0x1a0
[100527.162320]  __slab_alloc+0x1c/0x30
[100527.165892]  kmem_cache_alloc+0x19d/0x1d0
[100527.169985]  ? finish_wait+0x80/0x80
[100527.173648]  mempool_alloc+0x70/0x1a0
[100527.177392]  ? finish_wait+0x80/0x80
[100527.181050]  ? mempool_alloc+0x70/0x1a0
[100527.184967]  ? generic_make_request+0x192/0x3e0
[100527.189579]  bvec_alloc+0x82/0xe0
[100527.192984]  bio_alloc_bioset+0x12c/0x1d0
[100527.197076]  ext4_bio_write_page+0x302/0x4cb
[100527.201434]  mpage_submit_page+0x53/0x70
[100527.205437]  mpage_process_page_bufs+0xe6/0xf0
[100527.209962]  mpage_prepare_extent_to_map+0x1da/0x2b0
[100527.215008]  ext4_writepages+0x4b8/0xf00
[100527.219019]  ? mempool_alloc+0x70/0x1a0
[100527.222936]  ? update_load_avg+0x75/0x540
[100527.227027]  ? native_sched_clock+0x37/0x90
[100527.231292]  ? do_writepages+0x41/0xd0
[100527.235129]  ? ext4_mark_inode_dirty+0x1d0/0x1d0
[100527.239826]  do_writepages+0x41/0xd0
[100527.243485]  ? enqueue_entity+0xf6/0x680
[100527.247490]  ? wakeup_preempt_entity.isra.63+0x41/0x50
[100527.252707]  ? check_preempt_wakeup+0x113/0x230
[100527.257318]  __writeback_single_inode+0x3d/0x350
[100527.262024]  writeback_sb_inodes+0x1d0/0x460
[100527.266374]  __writeback_inodes_wb+0x5d/0xb0
[100527.270724]  wb_writeback+0x255/0x2f0
[100527.274470]  ? get_nr_inodes+0x35/0x50
[100527.278309]  ? cpumask_next+0x17/0x20
[100527.282061]  wb_workfn+0x342/0x400
[100527.285552]  ? dequeue_task_fair+0x3e/0x6d0
[100527.289817]  process_one_work+0x187/0x340
[100527.293907]  worker_thread+0x2e/0x380
[100527.297651]  ? pwq_unbound_release_workfn+0xd0/0xd0
[100527.302609]  kthread+0x112/0x130
[100527.305920]  ? kthread_create_worker_on_cpu+0x70/0x70
[100527.311052]  ret_from_fork+0x35/0x40
[100527.314715] Code: 80 58 38 88 48 89 c6 48 c1 e8 33 83 e0 07 48 c1 ee 36 48 8d 3c 40 48 8d 04 b8 48 c1 e0 07 48 03 04 f5 80 58 38 88 48 39 c1 74 17 <0f> 0b 45 31 e4 48 83 c4 28 44 89 e0 5b 5d 41 5c 41 5d 41 5e 41 
[100527.333651] RIP: move_freepages_block+0x167/0x2e0 RSP: ffffa66d0f5b3488
[100527.340343] ---[ end trace 10667fb2f15c4eae ]---
[100527.345043] WARNING: CPU: 1 PID: 11491 at kernel/exit.c:771 do_exit+0x4f/0xae0
[100527.352344] Modules linked in: hidp rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache rfcomm fuse xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_conntrack tun devlink ebtable_filter ebtables ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc bnep it87 hwmon_vid btrfs xor zstd_compress raid6_pq libcrc32c zstd_decompress xxhash intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm gpio_ich iTCO_wdt iTCO_vendor_support ppdev irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel intel_cstate intel_uncore intel_rapl_perf btusb btrtl btbcm btintel bluetooth snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic snd_hda_intel ecdh_generic rfkill snd_hda_codec i2c_i801 snd_hda_core snd_hwdep
[100527.423108]  snd_seq snd_seq_device snd_pcm lpc_ich snd_timer mei_me snd mei soundcore shpchp parport_pc parport nfsd nfs_acl lockd grace auth_rpcgss sunrpc binfmt_misc i915 crc32c_intel serio_raw i2c_algo_bit drm_kms_helper r8169 sata_via mii drm video
[100527.445583] CPU: 1 PID: 11491 Comm: kworker/u4:2 Tainted: G      D           4.17.6-200.fc28.x86_64 #1
[100527.454960] Hardware name: Gigabyte Technology Co., Ltd. H81M-S2PV/H81M-S2PV, BIOS F8 06/19/2014
[100527.463817] Workqueue: writeback wb_workfn (flush-253:3)
[100527.469209] RIP: 0010:do_exit+0x4f/0xae0
[100527.473211] RSP: 0018:ffffa66d0f5b3ed8 EFLAGS: 00010006
[100527.478516] RAX: ffffa66d0f5b3d90 RBX: ffff9aa7e7b83c00 RCX: 0000000000000000
[100527.485727] RDX: ffff9aa4c9b69040 RSI: 0000000000000000 RDI: ffffffff88266320
[100527.492937] RBP: 000000000000000b R08: 0000000000000005 R09: 0000000000000440
[100527.500148] R10: 0000000000000000 R11: ffffffff889981ae R12: ffffa66d0f5b33d8
[100527.507358] R13: 0000000000000000 R14: 0000000000000004 R15: ffffa66d0f5b33d8
[100527.514570] FS:  0000000000000000(0000) GS:ffff9aa81ef00000(0000) knlGS:0000000000000000
[100527.522734] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[100527.528558] CR2: 00001945e61d9008 CR3: 000000033420a004 CR4: 00000000000606e0
[100527.535766] Call Trace:
[100527.538299]  ? worker_thread+0x2e/0x380
[100527.542215]  ? pwq_unbound_release_workfn+0xd0/0xd0
[100527.547174]  ? kthread+0x112/0x130
[100527.550656]  rewind_stack_do_exit+0x17/0x20
[100527.554922] Code: 8b 04 25 28 00 00 00 48 89 44 24 40 31 c0 e8 a9 30 07 00 48 8b 83 18 08 00 00 48 85 c0 74 0e 48 8b 10 48 39 d0 0f 84 a8 04 00 00 <0f> 0b 65 44 8b 2d b7 4e f6 78 41 81 e5 00 ff 1f 00 44 89 6c 24 
[100527.573858] ---[ end trace 10667fb2f15c4eaf ]---