On 15/07/2024 14:05, Bitterblue Smith wrote: > Hi, > > To reproduce the problem, you need a computer with two wifi > devices supported by rtw88. It's especially easy to notice > the problem if one of the devices is USB and the other is PCI, > because the PCI device will have various values in the > registers 0x300..0x3ff, but the USB device will have all > 0xeaeaeaea there. > > 1. Let's assume the driver for the PCI device is already loaded. > I have RTL8822CE. > > 2. Mount debugfs: > > # mount -t debugfs none /sys/kernel/debug > > 3. Check page 0x300: > > # cat /sys/kernel/debug/ieee80211/phy0/rtw88/mac_3 > 00000300 f7138000 33330000 ffffb000 00000000 > ..... > > 4. Plug the USB device. I used RTL8811CU. > > 5. Check page 0x300 again: > > # cat /sys/kernel/debug/ieee80211/phy0/rtw88/mac_3 > 00000300 eaeaeaea eaeaeaea eaeaeaea eaeaeaea > ..... > > 6. Bonus: unload rtw88_8821cu and check page 0x300 again to get > a null pointer dereference: > > # rmmod rtw88_8821cu > # cat /sys/kernel/debug/ieee80211/phy0/rtw88/mac_3 I forgot to say: my kernel is 6.9.8-arch1-1 from Arch Linux. The problem also happens with kernel 6.9.8 plus rtw88 from rtw-next.
