In the Linux kernel, the following vulnerability has been resolved:
wifi: rtw88: use work to update rate to avoid RCU warning
The ieee80211_ops::sta_rc_update must be atomic, because
ieee80211_chan_bw_change() holds rcu_read lock while calling
drv_sta_rc_update(), so create a work to do original things.
Voluntary context switch within RCU read-side critical section!
WARNING: CPU: 0 PID: 4621 at kernel/rcu/tree_plugin.h:318
rcu_note_context_switch+0x571/0x5d0
CPU: 0 PID: 4621 Comm: kworker/u16:2 Tainted: G W OE
Workqueue: phy3 ieee80211_chswitch_work [mac80211]
RIP: 0010:rcu_note_context_switch+0x571/0x5d0
Call Trace:
<TASK>
__schedule+0xb0/0x1460
? __mod_timer+0x116/0x360
schedule+0x5a/0xc0
schedule_timeout+0x87/0x150
? trace_raw_output_tick_stop+0x60/0x60
wait_for_completion_timeout+0x7b/0x140
usb_start_wait_urb+0x82/0x160 [usbcore
usb_control_msg+0xe3/0x140 [usbcore
rtw_usb_read+0x88/0xe0 [rtw_usb
rtw_usb_read8+0xf/0x10 [rtw_usb
rtw_fw_send_h2c_command+0xa0/0x170 [rtw_core
rtw_fw_send_ra_info+0xc9/0xf0 [rtw_core
drv_sta_rc_update+0x7c/0x160 [mac80211
ieee80211_chan_bw_change+0xfb/0x110 [mac80211
ieee80211_change_chanctx+0x38/0x130 [mac80211
ieee80211_vif_use_reserved_switch+0x34e/0x900 [mac80211
ieee80211_link_use_reserved_context+0x88/0xe0 [mac80211
ieee80211_chswitch_work+0x95/0x170 [mac80211
process_one_work+0x201/0x410
worker_thread+0x4a/0x3b0
? process_one_work+0x410/0x410
kthread+0xe1/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x1f/0x30
</TASK>
