rtl8187: Fix crash on unload when using SLUB debug

Reported-by: Hin-Tak Leung <htl10@users.sourceforge.net>

After the code was modified to use urb anchors ("rtl8187: Use usb anchor
facilities to manage urbs"), rtl8187 began generating an intermittent GPF
on shutdown when using SLUB with debugging enabled. Furthermore, rebooting
the system with a ping running caused a GPF every time. There are two problems:
(1) incorrect locking in the rtl8187_rx_cb() routine, a pre-existing bug that
apparently had not been triggered before, and (2) duplicate freeing of receive
skbs that was probably introduced with the change to anchors.

Signed-off-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 8 deletions

diff --git a/drivers/net/wireless/rtl818x/rtl8187_dev.c b/drivers/net/wireless/rtl818x/rtl8187_dev.c
index 3900c479b4e7..00ce3ef39abe 100644
--- a/drivers/net/wireless/rtl818x/rtl8187_dev.c
+++ b/drivers/net/wireless/rtl818x/rtl8187_dev.c
@@ -294,15 +294,16 @@ static void rtl8187_rx_cb(struct urb *urb)
         int rate, signal;
         u32 flags;
         u32 quality;
+        unsigned long f;
 
-        spin_lock(&priv->rx_queue.lock);
+        spin_lock_irqsave(&priv->rx_queue.lock, f);
         if (skb->next)
                 __skb_unlink(skb, &priv->rx_queue);
         else {
-                spin_unlock(&priv->rx_queue.lock);
+                spin_unlock_irqrestore(&priv->rx_queue.lock, f);
                 return;
         }
-        spin_unlock(&priv->rx_queue.lock);
+        spin_unlock_irqrestore(&priv->rx_queue.lock, f);
         skb_put(skb, urb->actual_length);
 
         if (unlikely(urb->status)) {
@@ -942,7 +943,6 @@ static int rtl8187_start(struct ieee80211_hw *dev)
 static void rtl8187_stop(struct ieee80211_hw *dev)
 {
         struct rtl8187_priv *priv = dev->priv;
-        struct rtl8187_rx_info *info;
         struct sk_buff *skb;
         u32 reg;
 
@@ -961,10 +961,6 @@ static void rtl8187_stop(struct ieee80211_hw *dev)
         rtl818x_iowrite8(priv, &priv->map->CONFIG4, reg | RTL818X_CONFIG4_VCOOFF);
         rtl818x_iowrite8(priv, &priv->map->EEPROM_CMD, RTL818X_EEPROM_CMD_NORMAL);
 
-        while ((skb = skb_dequeue(&priv->rx_queue))) {
-                info = (struct rtl8187_rx_info *)skb->cb;
-                kfree_skb(skb);
-        }
         while ((skb = skb_dequeue(&priv->b_tx_status.queue)))
                 dev_kfree_skb_any(skb);