From: Marcin Ślusarz <mslusarz@xxxxxxxxx> Right now it's possible to hit NULL pointer dereference in rtw_rx_fill_rx_status on hw object and/or its fields because initialization routine can start getting USB replies before rtw_dev is fully setup. The stack trace looks like this: rtw_rx_fill_rx_status rtw8821c_query_rx_desc rtw_usb_rx_handler ... queue_work rtw_usb_read_port_complete ... usb_submit_urb rtw_usb_rx_resubmit rtw_usb_init_rx rtw_usb_probe So while we do the async stuff rtw_usb_probe continues and calls rtw_register_hw, which does all kinds of initialization (e.g. via ieee80211_register_hw) that rtw_rx_fill_rx_status relies on. Fix this by moving the first usb_submit_urb after everything is set up. For me, this bug manifested as: [ 8.893177] rtw_8821cu 1-1:1.2: band wrong, packet dropped [ 8.910904] rtw_8821cu 1-1:1.2: hw->conf.chandef.chan NULL in rtw_rx_fill_rx_status because I'm using Larry's backport of rtw88 driver with the NULL checks in rtw_rx_fill_rx_status. This should fix: https://marc.info/?l=linux-wireless&m=167907688311943&w=2 Signed-off-by: Marcin Ślusarz <mslusarz@xxxxxxxxx> Cc: Ping-Ke Shih <pkshih@xxxxxxxxxxx> Cc: Larry Finger <Larry.Finger@xxxxxxxxxxxx> Cc: Kalle Valo <kvalo@xxxxxxxxxx> Cc: linux-wireless@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx --- drivers/net/wireless/realtek/rtw88/usb.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/realtek/rtw88/usb.c b/drivers/net/wireless/realtek/rtw88/usb.c index a0188511099a..98f81e3ae13e 100644 --- a/drivers/net/wireless/realtek/rtw88/usb.c +++ b/drivers/net/wireless/realtek/rtw88/usb.c @@ -740,7 +740,6 @@ static struct rtw_hci_ops rtw_usb_ops = { static int rtw_usb_init_rx(struct rtw_dev *rtwdev) { struct rtw_usb *rtwusb = rtw_get_usb_priv(rtwdev); - int i; rtwusb->rxwq = create_singlethread_workqueue("rtw88_usb: rx wq"); if (!rtwusb->rxwq) { @@ -752,13 +751,19 @@ static int rtw_usb_init_rx(struct rtw_dev *rtwdev) INIT_WORK(&rtwusb->rx_work, rtw_usb_rx_handler); + return 0; +} + +static void rtw_usb_setup_rx(struct rtw_dev *rtwdev) +{ + struct rtw_usb *rtwusb = rtw_get_usb_priv(rtwdev); + int i; + for (i = 0; i < RTW_USB_RXCB_NUM; i++) { struct rx_usb_ctrl_block *rxcb = &rtwusb->rx_cb[i]; rtw_usb_rx_resubmit(rtwusb, rxcb); } - - return 0; } static void rtw_usb_deinit_rx(struct rtw_dev *rtwdev) @@ -895,6 +900,8 @@ int rtw_usb_probe(struct usb_interface *intf, const struct usb_device_id *id) goto err_destroy_rxwq; } + rtw_usb_setup_rx(rtwdev); + return 0; err_destroy_rxwq: -- 2.25.1
