From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Hartkopp Subject: [PATCH] can-raw: Fix skb_orphan_try handling Date: Fri, 30 Jul 2010 11:44:27 +0200 Message-ID: <4C529EFB.4090601@hartkopp.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: SocketCAN Core Mailing List , Linux Netdev List , Patrick Ohly To: Eric Dumazet Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org Errors-To: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org List-Id: netdev.vger.kernel.org Hello Eric, hello Patrick, Commit fc6055a5ba31e2c14e36e8939f9bf2b6d586a7f5 (net: Introduce skb_orphan_try()) allows an early orphan of the skb and takes care on tx timestamping, which needs the sk-reference in the skb on driver level. So does the can-raw socket, which has not been taken into account here. The patch below adds a 'prevent_sk_orphan' bit in the skb tx shared info, which fixes the problem discovered by Matthias Fuchs here: http://marc.info/?t=128030411900003&r=1&w=2 Even if it's not a primary tx timestamp topic it fits well into some skb shared tx context. Or should be find a different place for the information to protect the sk reference until it reaches the driver level? Regards, Oliver This patch applies on net-2.6 and would be a candidate for stable 2.6.34 also. Signed-off-by: Oliver Hartkopp --- diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f89e7fd..eb674b7 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -169,6 +169,7 @@ struct skb_shared_hwtstamps { * @software: generate software time stamp * @in_progress: device driver is going to provide * hardware time stamp + * @prevent_sk_orphan: make sk reference available on driver level * @flags: all shared_tx flags * * These flags are attached to packets as part of the @@ -178,7 +179,8 @@ union skb_shared_tx { struct { __u8 hardware:1, software:1, - in_progress:1; + in_progress:1, + prevent_sk_orphan:1; }; __u8 flags; }; diff --git a/net/can/raw.c b/net/can/raw.c index da99cf1..eedab37 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -655,6 +655,10 @@ static int raw_sendmsg(struct kiocb *iocb, struct socket *sock, err = sock_tx_timestamp(msg, sk, skb_tx(skb)); if (err < 0) goto free_skb; + + /* to be able to check the received tx sock reference in raw_rcv() */ + (skb_tx(skb))->prevent_sk_orphan = 1; + skb->dev = dev; skb->sk = sk;