I often (but not always) get kernel backtrace, when closing a luks device via
"cryptsetup close":
mh-backup-e[22132]: closing encrypted backup duplicate partition
/dev/mapper/backup_dup_secure:
kernel: WARNING: CPU: 11 PID: 3090 at kernel/workqueue.c:4335
destroy_workqueue+0x64/0x1d0
kernel: Modules linked in: dm_crypt algif_skcipher af_alg nls_utf8 isofs loop
ipt_MASQUERADE iptable_nat xt_addrtype br_netfilter veth xt_conntrack nf_nat
nf_conntrack_netlink nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xfrm_user
xfrm_algo overlay nfnetlink vhost_net vhost tap tun ebtable_filter ebtables
ip6table_filter ip6_tables iptable_filter ip_tables x_tables bpfilter bridge
stp llc iscsi_ibft iscsi_boot_sysfs msr intel_rapl sb_edac x86_pkg_temp_thermal
intel_powerclamp coretemp kvm_intel kvm irqbypass ast ttm crct10dif_pclmul
crc32_pclmul drm_kms_helper ipmi_ssif ghash_clmulni_intel igb iTCO_wdt drm
iTCO_vendor_support ipmi_si aesni_intel ptp mei_me fb_sys_fops ipmi_devintf
aes_x86_64 ioatdma syscopyarea crypto_simd sysfillrect pps_core pcspkr cryptd
sysimgblt mxm_wmi mei i2c_i801 i2c_algo_bit dca joydev glue_helper lpc_ich
ipmi_msghandler acpi_pad pcc_cpufreq button nfsd nfs_acl lockd grace
auth_rpcgss sunrpc hid_generic usbhid xhci_pci xhci_hcd ehci_pci ehci_hcd
usbcore sr_mod
kernel: cdrom wmi 3w_sas aacraid xfs libcrc32c crc32c_intel sg dm_multipath
dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua
kernel: CPU: 11 PID: 3090 Comm: cryptsetup Kdump: loaded Not tainted
5.1.15-7.ge222743-default #1 openSUSE Tumbleweed (unreleased)
kernel: Hardware name: Supermicro X10DRi/X10DRi, BIOS 2.1a 05/05/2017
kernel: RIP: 0010:destroy_workqueue+0x64/0x1d0
kernel: Code: 74 19 8b 30 85 f6 74 f1 0f 0b 48 89 ef e8 04 54 7f 00 5b 5d 41 5c
e9 bb fd ff ff 48 39 8b a0 00 00 00 74 0a 83 79 18 01 7e 04 <0f> 0b eb dc 8b 41
58 85 c0 0f 85 b0 00 00 00 48 8b 41 60 48 8d 51
kernel: RSP: 0018:ffffba89eb927c10 EFLAGS: 00010202
kernel: RAX: ffff9c81e74f8058 RBX: ffff9c8b4d805400 RCX: ffff9c81e74f8000
kernel: RDX: ffff9c81e74f8058 RSI: 0000000000000000 RDI: ffff9c8b4d805420
kernel: RBP: ffff9c8b4d805420 R08: 0000000000000000 R09: 0000000000000000
kernel: R10: 0000000000000000 R11: 0000000000000000 R12: ffffba89c64bf040
kernel: R13: ffff9c8b61eb0518 R14: ffff9c9637ea4200 R15: ffffba89eb927d10
kernel: FS: 00007f78172ae880(0000) GS:ffff9c963f940000(0000)
knlGS:0000000000000000
kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kernel: CR2: 00007fdb3f8a8a60 CR3: 00000010e5800003 CR4: 00000000001626e0
kernel: Call Trace:
kernel: crypt_dtr+0x4c/0x1c0 [dm_crypt]
kernel: dm_table_destroy+0x5e/0x120 [dm_mod]
kernel: __dm_destroy+0x10b/0x150 [dm_mod]
kernel: dev_remove+0xd3/0x110 [dm_mod]
kernel: ctl_ioctl+0x1b3/0x420 [dm_mod]
kernel: ? remove_all+0x30/0x30 [dm_mod]
kernel: dm_ctl_ioctl+0xa/0x10 [dm_mod]
kernel: do_vfs_ioctl+0x447/0x640
kernel: ? ksys_semctl.constprop.0+0x168/0x180
kernel: ? task_work_run+0x82/0xc0
kernel: ksys_ioctl+0x5e/0x90
kernel: __x64_sys_ioctl+0x16/0x20
kernel: do_syscall_64+0x60/0x120
kernel: entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: RIP: 0033:0x7f781633a587
kernel: Code: b3 66 90 48 8b 05 11 49 2c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff
ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff
73 01 c3 48 8b 0d e1 48 2c 00 f7 d8 64 89 01 48
kernel: RSP: 002b:00007fffcaeec648 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
kernel: RAX: ffffffffffffffda RBX: 00007f7816002040 RCX: 00007f781633a587
kernel: RDX: 000055c72952a580 RSI: 00000000c138fd04 RDI: 0000000000000003
kernel: RBP: 0000000000000000 R08: 0000000000000000 R09: 000055c729528e60
kernel: R10: 000055c729528e60 R11: 0000000000000246 R12: 0000000000000001
kernel: R13: 000055c72952a5b0 R14: 000055c72952a580 R15: 000055c7295200b0
kernel: ---[ end trace 515af4a31f849310 ]---