Comment 19 for bug 1886277

Log from another machine:
[ 1388.217900] BUG: unable to handle page fault for address: ffff8cf4f6fc5d86
[ 1388.217907] #PF: supervisor read access in kernel mode
[ 1388.217908] #PF: error_code(0x0000) - not-present page
[ 1388.217910] PGD 75201067 P4D 75201067 PUD 0
[ 1388.217913] Oops: 0000 [#4] SMP PTI
[ 1388.217916] CPU: 3 PID: 471 Comm: dmcrypt_write/2 Tainted: G D 5.4.0-40-generic #44-Ubuntu
[ 1388.217918] Hardware name: Hewlett-Packard HP EliteBook 8540w/1521, BIOS 68CVD Ver. F.60 11/11/2015
[ 1388.217923] RIP: 0010:kmem_cache_alloc+0x7e/0x230
[ 1388.217925] Code: 99 01 00 00 4d 8b 07 65 49 8b 50 08 65 4c 03 05 40 9d 76 4f 4d 8b 20 4d 85 e4 0f 84 85 01 00 00 41 8b 47 20 49 8b 3f 4c 01 e0 <48> 8b 18 48 89 c1 49 33 9f 70 01 00 00 4c 89 e0 48 0f c9 48 31 cb
[ 1388.217927] RSP: 0018:ffff9b3200977948 EFLAGS: 00010282
[ 1388.217928] RAX: ffff8cf4f6fc5d86 RBX: 0000000000000000 RCX: 0000000000000001
[ 1388.217929] RDX: 000000000000001f RSI: 0000000000092a20 RDI: 0000000000031ca0
[ 1388.217930] RBP: ffff9b3200977978 R08: ffff8cf4b3af1ca0 R09: ffff8cf4a08138b8
[ 1388.217931] R10: ffff8cf4b3ad7848 R11: 000000000000002d R12: ffff8cf4f6fc5d86
[ 1388.217932] R13: 0000000000092a20 R14: ffff8cf4b227c380 R15: ffff8cf4b227c380
[ 1388.217934] FS: 0000000000000000(0000) GS:ffff8cf4b3ac0000(0000) knlGS:0000000000000000
[ 1388.217935] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1388.217936] CR2: ffff8cf4f6fc5d86 CR3: 000000007480a000 CR4: 00000000000006e0
[ 1388.217937] Call Trace:
[ 1388.217944] ? mempool_alloc_slab+0x17/0x20
[ 1388.217948] mempool_alloc_slab+0x17/0x20
[ 1388.217950] mempool_alloc+0x64/0x180
[ 1388.217956] ? try_to_wake_up+0x224/0x6a0
[ 1388.217960] ? __blk_bios_map_sg+0xe5/0x4c0
[ 1388.217964] sg_pool_alloc+0x4f/0x60
[ 1388.217968] __sg_alloc_table+0x10b/0x170
[ 1388.217971] sg_alloc_table_chained+0x47/0xa0
[ 1388.217972] ? mac_pton+0xb0/0xb0
[ 1388.217976] scsi_init_io+0x52/0x180
[ 1388.217981] sd_setup_read_write_cmnd+0x67/0x710
[ 1388.217984] ? __blk_mq_get_tag+0x28/0x80
[ 1388.217986] sd_init_command+0x11a/0x472
[ 1388.217988] scsi_queue_rq+0x32e/0xa00
[ 1388.217990] blk_mq_dispatch_rq_list+0x96/0x5a0
[ 1388.217993] ? deadline_remove_request+0x4e/0xb0
[ 1388.217995] ? dd_dispatch_request+0x1/0x1f0
[ 1388.217998] blk_mq_do_dispatch_sched+0x67/0x100
[ 1388.218000] blk_mq_sched_dispatch_requests+0x12d/0x180
[ 1388.218003] __blk_mq_run_hw_queue+0x5a/0x110
[ 1388.218005] __blk_mq_delay_run_hw_queue+0x15b/0x160
[ 1388.218008] blk_mq_run_hw_queue+0x92/0x120
[ 1388.218010] blk_mq_sched_insert_requests+0x74/0x100
[ 1388.218012] blk_mq_flush_plug_list+0x1e8/0x290
[ 1388.218013] ? blk_mq_make_request+0x35f/0x5b0
[ 1388.218016] blk_flush_plug_list+0xe3/0x110
[ 1388.218018] blk_finish_plug+0x26/0x34
[ 1388.218024] dmcrypt_write+0x155/0x170 [dm_crypt]
[ 1388.218028] kthread+0x104/0x140
[ 1388.218030] ? crypt_iv_lmk_ctr+0xd0/0xd0 [dm_crypt]
[ 1388.218032] ? kthread_park+0x90/0x90
[ 1388.218037] ret_from_fork+0x35/0x40
[ 1388.218039] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 nfs lockd grace fscache bnep bluetooth ecdh_generic ecc msr nls_iso8859_1 pata_pcmcia snd_hda_codec_hdmi snd_hda_codec_idt snd_hda_codec_generic ledtrig_audio snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core snd_hwdep snd_pcm intel_powerclamp coretemp kvm_intel snd_seq_midi snd_seq_midi_event kvm snd_rawmidi intel_cstate uvcvideo pcmcia iwldvm snd_seq mac80211 videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 libarc4 input_leds joydev videobuf2_common r852 hp_wmi snd_seq_device sm_common iwlwifi snd_timer sparse_keymap serio_raw videodev nand intel_ips nand_ecc mc bch r592 yenta_socket nandcore mtd pcmcia_rsrc memstick snd pcmcia_core cfg80211 mei_me wmi_bmof mei soundcore hp_accel lis3lv02d input_polldev tpm_infineon mac_hid nf_log_ipv6 ip6t_REJECT nf_reject_ipv6 xt_hl ip6t_rt nf_log_ipv4 nf_log_common ipt_REJECT nf_reject_ipv4 xt_LOG xt_limit xt_addrtype xt_tcpudp xt_conntrack nf_conntrack nf_defrag_ipv6
[ 1388.218087] nf_defrag_ipv4 libcrc32c sch_fq_codel ip6table_filter ip6_tables iptable_filter parport_pc ppdev bpfilter lp parport sunrpc ip_tables x_tables autofs4 dm_crypt crct10dif_pclmul nouveau crc32_pclmul mxm_wmi i2c_algo_bit ghash_clmulni_intel ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops aesni_intel firewire_ohci sdhci_pci crypto_simd firewire_core cqhci ahci psmouse cryptd glue_helper sdhci libahci drm crc_itu_t lpc_ich e1000e wmi video
[ 1388.218115] CR2: ffff8cf4f6fc5d86
[ 1388.218119] ---[ end trace 53f76f5ab9db54e9 ]---
[ 1388.218121] RIP: 0010:kmem_cache_alloc+0x7e/0x230
[ 1388.218124] Code: 99 01 00 00 4d 8b 07 65 49 8b 50 08 65 4c 03 05 40 9d 76 4f 4d 8b 20 4d 85 e4 0f 84 85 01 00 00 41 8b 47 20 49 8b 3f 4c 01 e0 <48> 8b 18 48 89 c1 49 33 9f 70 01 00 00 4c 89 e0 48 0f c9 48 31 cb
[ 1388.218125] RSP: 0018:ffff9b32020e7900 EFLAGS: 00010282
[ 1388.218127] RAX: ffff8cf4f6fc5d86 RBX: 0000000000000000 RCX: ffffffffb2351218
[ 1388.218129] RDX: 000000000000001f RSI: 0000000000092880 RDI: 0000000000031ca0
[ 1388.218130] RBP: ffff9b32020e7930 R08: ffff8cf4b3af1ca0 R09: ffff8cf4ae1c0b00
[ 1388.218132] R10: 0000000000000001 R11: 00000000000000d4 R12: ffff8cf4f6fc5d86
[ 1388.218134] R13: 0000000000092880 R14: ffff8cf4b227c380 R15: ffff8cf4b227c380
[ 1388.218136] FS: 0000000000000000(0000) GS:ffff8cf4b3ac0000(0000) knlGS:0000000000000000
[ 1388.218137] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1388.218138] CR2: ffff8cf4f6fc5d86 CR3: 000000007480a000 CR4: 00000000000006e0