[BUG] wifi: mac80211: Unable to handle kernel paging request

[BUG] wifi: mac80211: Unable to handle kernel paging request

[Ladislav Michl]

Hi,

following issue was triggered while debugging xHCI on custom Cavium
Octeon III (MIPS) board with linux-6.1.4.

Ralink 802.11n WLAN dongle is inserted into USB port:
usb 1-1: new high-speed USB device number 29 using xhci-hcd
usb 1-1: New USB device found, idVendor=148f, idProduct=5370, bcdDevice= 1.01
usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1: Product: 802.11 n WLAN
usb 1-1: Manufacturer: Ralink
usb 1-1: SerialNumber: 1.0
usb 1-1: reset high-speed USB device number 29 using xhci-hcd
ieee80211 phy16785: rt2x00_set_rt: Info - RT chipset 5390, rev 0502 detected
ieee80211 phy16785: rt2x00_set_rf: Info - RF chipset 5370 detected
and a script is periodically enabling and disabling it. After a few rounds
kernel panics:
Unable to handle kernel paging request at virtual address ffffffff8117ca0c
...
Call Trace:
 [<ffffffff8117ca0c>] del_timer+0x14/0x68
 [<ffffffff8158dd30>] led_blink_set+0x30/0x80
 [<ffffffff8158f4d0>] led_trigger_blink+0x48/0x78
 [<ffffffff818b265c>] tpt_trig_timer+0x10c/0x120
 [<ffffffff8117c48c>] call_timer_fn.constprop.0+0x24/0x98
 [<ffffffff8117c908>] run_timer_softirq+0x318/0x3a0
 [<ffffffff818ed580>] __do_softirq+0x100/0x2b0
 [<ffffffff81104940>] plat_irq_dispatch+0xb0/0xd0
 [<ffffffff811131a0>] handle_int+0x140/0x14c
 [<ffffffff81113020>] __r4k_wait+0x20/0x40
 [<ffffffff818ed3f8>] default_idle_call+0x30/0x48
 [<ffffffff8115b85c>] do_idle+0x74/0xe0
 [<ffffffff8115bb68>] cpu_startup_entry+0x18/0x28
 [<ffffffff818e4640>] kernel_init+0x0/0x110

It seems timer is still running at the time device is removed. Disabling
MAC80211_LEDS makes issue dissapear. Does it ring a bell?

	ladis