Hi,

from the kernel log when loading the 8821au kernel module (Arch linux with 5.12 kernel):

[ 6472.495584] ------------[ cut here ]------------
[ 6472.495585] WARNING: CPU: 1 PID: 110192 at net/wireless/core.c:912 wiphy_register+0x734/0x9f0 [cfg80211]
[ 6472.495622] Modules linked in: 8821au(OE+) nfsv3 nfs_acl nfs lockd grace sunrpc nfs_ssc fscache ds2490 wire pl2303 hid_logitech ftdi_sio ff_memless wacom xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_filter iptable_nat nf_nat nf_co
nntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter hid_cherry dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c loop dm_mod uas usb_storage snd_usb_audio snd_usbmidi_lib usbhid snd_rawmidi snd_seq_device 8021q garp mrp uvcvideo btusb videobuf2_vmalloc
btrtl videobuf2_memops btbcm videobuf2_v4l2 btintel videobuf2_common bluetooth videodev cdc_mbim cdc_wdm cdc_ncm cdc_ether mc usbnet qcserial usb_wwan mii ecdh_generic ecc joydev mousedev snd_soc_skl snd_soc_hdac_hda snd_hda_codec_hdmi snd_hda_ext_core intel_rapl_m
sr snd_soc_sst_ipc intel_rapl_common snd_soc_sst_dsp snd_soc_acpi_intel_match snd_soc_acpi x86_pkg_temp_thermal intel_powerclamp snd_soc_core snd_hda_codec_realtek kvm_intel snd_hda_codec_generic
[ 6472.495670]  ledtrig_audio snd_compress ac97_bus iwlmvm bridge snd_pcm_dmaengine stp llc kvm mac80211 snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec coretemp irqbypass crct10dif_pclmul libarc4 crc32_pclmul ghash_clmulni_intel i915 iwlwifi aesni_i
ntel snd_hda_core crypto_simd iTCO_wdt snd_hwdep cryptd snd_pcm mei_hdcp rapl intel_pmc_bxt intel_cstate ee1004 iTCO_vendor_support intel_wmi_thunderbolt i2c_algo_bit drm_kms_helper intel_uncore cfg80211 snd_timer cec intel_gtt mei_me pcspkr psmouse e1000e snd sysco
pyarea i2c_i801 sysfillrect soundcore i2c_smbus rfkill intel_xhci_usb_role_switch sysimgblt mei fb_sys_fops roles mac_hid wmi tpm_crb fujitsu_laptop tpm_tis tpm_tis_core sparse_keymap video acpi_pad tpm rng_core sg drm crypto_user fuse agpgart bpf_preload ip_tables
x_tables ext4 crc32c_generic crc16 mbcache jbd2 mmc_block serio_raw atkbd libps2 crc32c_intel sdhci_pci cqhci sr_mod sdhci i8042 xhci_pci mmc_core cdrom xhci_pci_renesas serio [last unloaded: 8821au]                                                                    
[ 6472.495726] CPU: 1 PID: 110192 Comm: modprobe Tainted: G        W  OE     5.12.14-arch1-1 #1
[ 6472.495729] Hardware name: FUJITSU LIFEBOOK E756/FJNB293, BIOS Version 1.13 12/21/2015
[ 6472.495730] RIP: 0010:wiphy_register+0x734/0x9f0 [cfg80211]
[ 6472.495750] Code: e9 9b fb ff ff 48 83 78 08 00 75 bd 0f 0b b8 ea ff ff ff e9 88 fb ff ff 80 7a 1e 00 74 38 0f 0b b8 ea ff ff ff e9 76 fb ff ff <0f> 0b b8 ea ff ff ff e9 6a fb ff ff 80 7a 1e 00 0f 84 77 fe ff ff
[ 6472.495752] RSP: 0018:ffffa489c24af960 EFLAGS: 00010246
[ 6472.495754] RAX: ffffffffc19ac550 RBX: ffff93644f98e300 RCX: ffffffffc19ac540
[ 6472.495755] RDX: ffffffffc19ac5b0 RSI: 000000000000001c RDI: 0000000000000001
[ 6472.495756] RBP: ffffa489c24af9e0 R08: 0000000000000004 R09: 0000000000000005
[ 6472.495758] R10: 0000000000000000 R11: 0000000000000000 R12: ffff93644f98e300
[ 6472.495759] R13: ffffa489c24af970 R14: ffffa489c11fc41a R15: ffff93643eaeb000
[ 6472.495760] FS:  00007f3606bc7740(0000) GS:ffff9365e3480000(0000) knlGS:0000000000000000
[ 6472.495762] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 6472.495764] CR2: 00007f3606cc7ce0 CR3: 000000029e4b6003 CR4: 00000000003706e0
[ 6472.495765] Call Trace:
[ 6472.495767]  ? __rtnl_unlock+0x24/0x40
[ 6472.495774]  ? rtw_regd_apply_flags+0xd1/0xe2 [8821au]
[ 6472.495863]  rtw_wiphy_register+0x2a/0x54 [8821au]
[ 6472.495936]  rtw_cfg80211_ndev_res_register+0x15/0x56 [8821au]
[ 6472.496007]  rtw_os_ndev_register+0x115/0x177 [8821au]
[ 6472.496094]  rtw_os_ndevs_register+0xa7/0xf2 [8821au]
[ 6472.496170]  rtw_os_ndevs_init+0x24/0x38 [8821au]
[ 6472.496236]  rtw_drv_init+0x4a5/0x5c6 [8821au]
[ 6472.496305]  usb_probe_interface+0xe2/0x2a0
[ 6472.496308]  really_probe+0xf2/0x440
[ 6472.496312]  driver_probe_device+0xe1/0x150
[ 6472.496315]  device_driver_attach+0xa1/0xb0
[ 6472.496317]  __driver_attach+0x8a/0x150
[ 6472.496319]  ? device_driver_attach+0xb0/0xb0
[ 6472.496320]  ? device_driver_attach+0xb0/0xb0
[ 6472.496321]  bus_for_each_dev+0x89/0xd0
[ 6472.496325]  bus_add_driver+0x12b/0x1e0
[ 6472.496328]  driver_register+0x8f/0xe0
[ 6472.496330]  usb_register_driver+0x84/0x120
[ 6472.496332]  ? 0xffffffffc1ab9000
[ 6472.496334]  rtw_drv_entry+0xc0/0x1000 [8821au]
[ 6472.496375]  do_one_initcall+0x57/0x220
[ 6472.496379]  do_init_module+0x5c/0x270
[ 6472.496382]  load_module+0x2545/0x2740
[ 6472.496386]  ? __do_sys_finit_module+0xb1/0x110
[ 6472.496388]  __do_sys_finit_module+0xb1/0x110
[ 6472.496390]  do_syscall_64+0x33/0x40
[ 6472.496394]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 6472.496397] RIP: 0033:0x7f3606ced18d
[ 6472.496399] Code: b4 0c 00 0f 05 eb a9 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b3 6c 0c 00 f7 d8 64 89 01 48
[ 6472.496401] RSP: 002b:00007ffc0f9d9e28 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 6472.496403] RAX: ffffffffffffffda RBX: 000055bdcae38c40 RCX: 00007f3606ced18d
[ 6472.496404] RDX: 0000000000000000 RSI: 000055bdc9cb6270 RDI: 0000000000000003
[ 6472.496405] RBP: 0000000000040000 R08: 0000000000000000 R09: 000055bdcae40520
[ 6472.496406] R10: 0000000000000003 R11: 0000000000000246 R12: 000055bdc9cb6270
[ 6472.496407] R13: 0000000000000000 R14: 000055bdcae38d50 R15: 000055bdcae38c40
[ 6472.496409] ---[ end trace b26197e94f2b1cb1 ]---

Kind regards

Nazdravi