With commit e49656147359 {"rtlwifi: Use dev_kfree_skb_irq instead of kfree_skb"), the method used to free an skb was changed because the kfree_skb() was inside a spinlock. What was forgotten is that kfree_skb() guards against a NULL value for the argument. Routine dev_kfree_skb_irq() does not, and a test is needed to prevent kernel panics. Fixes: commit e49656147359 {"rtlwifi: Use dev_kfree_skb_irq instead of kfree_skb") Signed-off-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx> Cc: Stable <stable@xxxxxxxxxxxxxxx> (4.9+) Cc: Wei Yongjun <weiyongjun1@xxxxxxxxxx> --- Kalle, This change should be sent to mainline during the 4.10 merge period, or as soon as possible. Thanks, Larry --- drivers/net/wireless/realtek/rtlwifi/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/realtek/rtlwifi/core.c b/drivers/net/wireless/realtek/rtlwifi/core.c index 955055b..df8b977 100644 --- a/drivers/net/wireless/realtek/rtlwifi/core.c +++ b/drivers/net/wireless/realtek/rtlwifi/core.c @@ -1823,7 +1823,8 @@ bool rtl_cmd_send_packet(struct ieee80211_hw *hw, struct sk_buff *skb) spin_lock_irqsave(&rtlpriv->locks.irq_th_lock, flags); pskb = __skb_dequeue(&ring->queue); - dev_kfree_skb_irq(pskb); + if (pskb) + dev_kfree_skb_irq(pskb); /*this is wrong, fill_tx_cmddesc needs update*/ pdesc = &ring->desc[0]; -- 2.10.2