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.fin...@lwfinger.net>
Cc: Stable <sta...@vger.kernel.org> (4.9+)
Cc: Wei Yongjun <weiyongj...@huawei.com>
---
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

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