linux-kernel - Re: [OOPS] In __netif_receive_skb

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Date:	Mon, 11 Jan 2016 18:25:15 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Salam Noureddine <noureddine@...sta.com>
Cc:	Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Pali Rohár <pali.rohar@...il.com>,
	Network Development <netdev@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Sebastian Reichel <sre@...nel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>
Subject: Re: [OOPS] In __netif_receive_skb_core

On Mon, 2016-01-11 at 18:21 -0800, Eric Dumazet wrote:
> On Mon, 2016-01-11 at 17:19 -0800, Salam Noureddine wrote:
> > It must be that skb->dev was changed to NULL inside of
> > __netif_receive_skb_core, otherwise we would have crashed much
> > earlier. Also, orig_dev is saved at the beginning. Possibly a device
> > is layered on top of the original device.
> 
> Please do not top post on netdev / lkml mailing lists.
> 
> My guess is a protocol handler queued the skb without calling
> skb_share_check()
> 

OK please try this fix :

diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c
index 10d42f3220ab..f925753668a7 100644
--- a/net/phonet/af_phonet.c
+++ b/net/phonet/af_phonet.c
@@ -377,6 +377,10 @@ static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
 	struct sockaddr_pn sa;
 	u16 len;
 
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		return NET_RX_DROP;
+
 	/* check we have at least a full Phonet header */
 	if (!pskb_pull(skb, sizeof(struct phonethdr)))
 		goto out;