RCU WARNING Splat from rtw8822bu

[Larry Finger <Larry.Finger@lwfinger.net>]

Hi,

I got the following WARNING splat from rtw8822bu. Driver rtw89_8852be was 
loaded, but inactive. This is the only instance of this warning in my logs even 
though I have been testing this driver quite a lot.

[18177.576316] ------------[ cut here ]------------
[18177.576320] Voluntary context switch within RCU read-side critical section!
[18177.576323] WARNING: CPU: 0 PID: 4621 at kernel/rcu/tree_plugin.h:318 
rcu_note_context_switch+0x571/0x5d0
[18177.576330] Modules linked in: rtw89_8852be(E) rtw89_8852b(E) rtw89_pci(E) 
ccm(E) rfcomm(E) rpcsec_gss_krb5(E) auth_rpcgss(E) nfsv4(E) dns_resolver(E) 
nfs(E) lockd(E) grace(E) sunrpc(E) fscache(E) netfs(E) af_packet(E) cmac(E) 
algif_hash(E) algif_skcipher(E) af_alg(E) bnep(E) vboxnetadp(OE) vboxnetflt(OE) 
qrtr(E) btusb(E) btrtl(E) btbcm(E) vboxdrv(OE) btintel(E) btmtk(E) bluetooth(E) 
rtw88_8822bu(E) rtw_usb(OE) rtw_8822b(OE) rtw_core(OE) ecdh_generic(E) 
binfmt_misc(E) nls_iso8859_1(E) nls_cp437(E) vfat(E) fat(E) intel_rapl_msr(E) 
intel_rapl_common(E) x86_pkg_temp_thermal(E) intel_powerclamp(E) coretemp(E) 
kvm_intel(E) iTCO_wdt(E) iwlmvm(E) spi_intel_platform(E) intel_pmc_bxt(E) 
rtw89_core(E) snd_hda_codec_realtek(E) spi_intel(E) iTCO_vendor_support(E) 
mei_hdcp(E) mei_pxp(E) snd_hda_codec_generic(E) ledtrig_audio(E) kvm(E) 
snd_hda_codec_hdmi(E) irqbypass(E) mac80211(E) pcspkr(E) wmi_bmof(E) iwlwifi(E) 
snd_hda_intel(E) snd_intel_dspcfg(E) snd_hda_codec(E) libarc4(E) snd_hwdep(E) 
lpc_ich(E) snd_hda_core(E) cfg80211(E)
[18177.576372]  snd_pcm(E) toshiba_acpi(E) snd_timer(E) mei_me(E) snd(E) 
sparse_keymap(E) e1000e(E) tiny_power_button(E) soundcore(E) mei(E) thermal(E) 
industrialio(E) toshiba_bluetooth(E) tpm_infineon(E) battery(E) button(E) ac(E) 
joydev(E) fuse(E) configfs(E) dmi_sysfs(E) ext4(E) mbcache(E) jbd2(E) 
crct10dif_pclmul(E) crc32_pclmul(E) crc32c_intel(E) polyval_clmulni(E) 
polyval_generic(E) ghash_clmulni_intel(E) sha512_ssse3(E) i915(E) 
i2c_algo_bit(E) drm_buddy(E) drm_display_helper(E) xhci_pci(E) rtsx_pci_sdmmc(E) 
xhci_pci_renesas(E) drm_kms_helper(E) syscopyarea(E) sysfillrect(E) sysimgblt(E) 
cec(E) aesni_intel(E) ttm(E) sr_mod(E) mmc_core(E) crypto_simd(E) ehci_pci(E) 
xhci_hcd(E) cryptd(E) ehci_hcd(E) cdrom(E) rtsx_pci(E) drm(E) usbcore(E) 
video(E) wmi(E) serio_raw(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) 
scsi_dh_emc(E) scsi_dh_alua(E) msr(E)
[18177.576406] Unloaded tainted modules: rtw89_8852b(E):1 rtw89_pci(E):1 
rtw89_8852be(E):1 rtw_8822bu(OE):1 acpi_cpufreq(E):1 ie31200_edac(E):1 [last 
unloaded: rtw89_8852b(E)]
[18177.576414] CPU: 0 PID: 4621 Comm: kworker/u16:2 Tainted: G        W  OE 
6.4.0-rc0-gddc703714c0b-dirty #60 b8779e6b3528dc339549b3de720a59d95f1c4cf5
[18177.576417] Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.50 
   09/29/2014
[18177.576418] Workqueue: phy3 ieee80211_chswitch_work [mac80211]
[18177.576469] RIP: 0010:rcu_note_context_switch+0x571/0x5d0
[18177.576472] Code: 00 00 00 00 0f 85 65 fd ff ff 49 89 84 24 a0 00 00 00 e9 58 
fd ff ff 48 c7 c7 60 66 ec b0 c6 05 96 5f 76 01 01 e8 af 0d f6 ff <0f> 0b e9 de 
fa ff ff c6 43 11 00 48 8b 73 20 ba 01 00 00 00 48 8b
[18177.576473] RSP: 0018:ffffa937cb0afa50 EFLAGS: 00010086
[18177.576475] RAX: 0000000000000000 RBX: ffff8d5b23233e80 RCX: 0000000000000027
[18177.576476] RDX: ffff8d5b232224c8 RSI: 0000000000000001 RDI: ffff8d5b232224c0
[18177.576477] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffa937cb0af8f8
[18177.576478] R10: 0000000000000003 R11: ffff8d5b2f546fa8 R12: ffff8d5b23233040
[18177.576479] R13: ffff8d59a3475100 R14: ffff8d59a3475100 R15: ffffa937cb0afc00
[18177.576480] FS:  0000000000000000(0000) GS:ffff8d5b23200000(0000) 
knlGS:0000000000000000
[18177.576481] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[18177.576483] CR2: 00007f0b70230fc4 CR3: 000000010dc34004 CR4: 00000000001706f0
[18177.576484] Call Trace:
[18177.576485]  <TASK>
[18177.576486]  __schedule+0xb0/0x1460
[18177.576492]  ? __mod_timer+0x116/0x360
[18177.576495]  schedule+0x5a/0xc0
[18177.576497]  schedule_timeout+0x87/0x150
[18177.576500]  ? trace_raw_output_tick_stop+0x60/0x60
[18177.576502]  wait_for_completion_timeout+0x7b/0x140
[18177.576505]  usb_start_wait_urb+0x82/0x160 [usbcore 
3226d314cb1ead5093f872b7ec783a0667c9bdaa]
[18177.576529]  usb_control_msg+0xe3/0x140 [usbcore 
3226d314cb1ead5093f872b7ec783a0667c9bdaa]
[18177.576547]  rtw_usb_read+0x88/0xe0 [rtw_usb 
ea7c9ef4045ae47f255f6c8259d13b8259ad6fcd]
[18177.576552]  rtw_usb_read8+0xf/0x10 [rtw_usb 
ea7c9ef4045ae47f255f6c8259d13b8259ad6fcd]
[18177.576556]  rtw_fw_send_h2c_command+0xa0/0x170 [rtw_core 
d6ae475d8b91a371feee3d61c7b6a8180a974991]
[18177.576571]  rtw_fw_send_ra_info+0xc9/0xf0 [rtw_core 
d6ae475d8b91a371feee3d61c7b6a8180a974991]
[18177.576584]  drv_sta_rc_update+0x7c/0x160 [mac80211 
c276bd403dbb068b66ac9ffb0a8f27d6e63e5c7c]
[18177.576613]  ieee80211_chan_bw_change+0xfb/0x110 [mac80211 
c276bd403dbb068b66ac9ffb0a8f27d6e63e5c7c]
[18177.576651]  ieee80211_change_chanctx+0x38/0x130 [mac80211 
c276bd403dbb068b66ac9ffb0a8f27d6e63e5c7c]
[18177.576688]  ieee80211_vif_use_reserved_switch+0x34e/0x900 [mac80211 
c276bd403dbb068b66ac9ffb0a8f27d6e63e5c7c]
[18177.576724]  ieee80211_link_use_reserved_context+0x88/0xe0 [mac80211 
c276bd403dbb068b66ac9ffb0a8f27d6e63e5c7c]
[18177.576760]  ieee80211_chswitch_work+0x95/0x170 [mac80211 
c276bd403dbb068b66ac9ffb0a8f27d6e63e5c7c]
[18177.576798]  process_one_work+0x201/0x410
[18177.576800]  worker_thread+0x4a/0x3b0
[18177.576802]  ? process_one_work+0x410/0x410
[18177.576803]  kthread+0xe1/0x110
[18177.576805]  ? kthread_complete_and_exit+0x20/0x20
[18177.576807]  ret_from_fork+0x1f/0x30
[18177.576810]  </TASK>
[18177.576811] ---[ end trace 0000000000000000 ]---

Thanks,

Larry