This is a note to let you know that I've just added the patch titled drivers/net/wan/hdlc_fr: Fix a double free in pvc_xmit to the 5.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drivers-net-wan-hdlc_fr-fix-a-double-free-in-pvc_xmi.patch and it can be found in the queue-5.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 9c07417b0cebd5d049805d6bb86b5624ffff82b0 Author: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx> Date: Sun Mar 28 00:50:08 2021 -0700 drivers/net/wan/hdlc_fr: Fix a double free in pvc_xmit [ Upstream commit 1b479fb801602b22512f53c19b1f93a4fc5d5d9d ] In pvc_xmit, if __skb_pad(skb, pad, false) failed, it will free the skb in the first time and goto drop. But the same skb is freed by kfree_skb(skb) in the second time in drop. Maintaining the original function unchanged, my patch adds a new label out to avoid the double free if __skb_pad() failed. Fixes: f5083d0cee08a ("drivers/net/wan/hdlc_fr: Improvements to the code of pvc_xmit") Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c index 0720f5f92caa..4d9dc7d15908 100644 --- a/drivers/net/wan/hdlc_fr.c +++ b/drivers/net/wan/hdlc_fr.c @@ -415,7 +415,7 @@ static netdev_tx_t pvc_xmit(struct sk_buff *skb, struct net_device *dev) if (pad > 0) { /* Pad the frame with zeros */ if (__skb_pad(skb, pad, false)) - goto drop; + goto out; skb_put(skb, pad); } } @@ -448,8 +448,9 @@ static netdev_tx_t pvc_xmit(struct sk_buff *skb, struct net_device *dev) return NETDEV_TX_OK; drop: - dev->stats.tx_dropped++; kfree_skb(skb); +out: + dev->stats.tx_dropped++; return NETDEV_TX_OK; }