wifi: rtl818x: Kill URBs before clearing tx status queue

In rtl8187_stop() move the call of usb_kill_anchored_urbs() before clearing
b_tx_status.queue. This change prevents callbacks from using already freed
skb due to anchor was not killed before freeing such skb.

 BUG: kernel NULL pointer dereference, address: 0000000000000080
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: Oops: 0000 [#1] SMP NOPTI
 CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Not tainted 6.15.0 #8 PREEMPT(voluntary)
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
 RIP: 0010:ieee80211_tx_status_irqsafe+0x21/0xc0 [mac80211]
 Call Trace:
  <IRQ>
  rtl8187_tx_cb+0x116/0x150 [rtl8187]
  __usb_hcd_giveback_urb+0x9d/0x120
  usb_giveback_urb_bh+0xbb/0x140
  process_one_work+0x19b/0x3c0
  bh_worker+0x1a7/0x210
  tasklet_action+0x10/0x30
  handle_softirqs+0xf0/0x340
  __irq_exit_rcu+0xcd/0xf0
  common_interrupt+0x85/0xa0
  </IRQ>

Tested on RTL8187BvE device.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: c1db52b ("rtl8187: Use usb anchor facilities to manage urbs")
Signed-off-by: Daniil Dulov <[email protected]>
Reviewed-by: Ping-Ke Shih <[email protected]>
Signed-off-by: Ping-Ke Shih <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: Daniil Dulov

drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c

@@ -1041,10 +1041,11 @@ static void rtl8187_stop(struct ieee80211_hw *dev, bool suspend)
 	rtl818x_iowrite8(priv, &priv->map->CONFIG4, reg | RTL818X_CONFIG4_VCOOFF);
 	rtl818x_iowrite8(priv, &priv->map->EEPROM_CMD, RTL818X_EEPROM_CMD_NORMAL);
 
+	usb_kill_anchored_urbs(&priv->anchored);
+
 	while ((skb = skb_dequeue(&priv->b_tx_status.queue)))
 		dev_kfree_skb_any(skb);
 
-	usb_kill_anchored_urbs(&priv->anchored);
 	mutex_unlock(&priv->conf_mutex);
 
 	if (!priv->is_rtl8187b)