Commit cff0d6e6 authored Aug 03, 2010 by Oliver Hartkopp Committed by David S. Miller Aug 03, 2010

can-raw: Fix skb_orphan_try handling

Commit fc6055a5 (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?

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 3578b0c8

include/linux/skbuff.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -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;
		};

net/can/raw.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -650,6 +650,10 @@ 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;

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