From d3b58c47d330de8c29898fe9746f7530408f8a59 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Fri, 26 Jun 2015 11:58:19 +0200 Subject: can: replace timestamp as unique skb attribute Commit 514ac99c64b "can: fix multiple delivery of a single CAN frame for overlapping CAN filters" requires the skb->tstamp to be set to check for identical CAN skbs. Without timestamping to be required by user space applications this timestamp was not generated which lead to commit 36c01245eb8 "can: fix loss of CAN frames in raw_rcv" - which forces the timestamp to be set in all CAN related skbuffs by introducing several __net_timestamp() calls. This forces e.g. out of tree drivers which are not using alloc_can{,fd}_skb() to add __net_timestamp() after skbuff creation to prevent the frame loss fixed in mainline Linux. This patch removes the timestamp dependency and uses an atomic counter to create an unique identifier together with the skbuff pointer. Btw: the new skbcnt element introduced in struct can_skb_priv has to be initialized with zero in out-of-tree drivers which are not using alloc_can{,fd}_skb() too. Signed-off-by: Oliver Hartkopp Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/slcan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/can/slcan.c') diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c index f64f5290d6f8..a23a7af8eb9a 100644 --- a/drivers/net/can/slcan.c +++ b/drivers/net/can/slcan.c @@ -207,7 +207,6 @@ static void slc_bump(struct slcan *sl) if (!skb) return; - __net_timestamp(skb); skb->dev = sl->dev; skb->protocol = htons(ETH_P_CAN); skb->pkt_type = PACKET_BROADCAST; @@ -215,6 +214,7 @@ static void slc_bump(struct slcan *sl) can_skb_reserve(skb); can_skb_prv(skb)->ifindex = sl->dev->ifindex; + can_skb_prv(skb)->skbcnt = 0; memcpy(skb_put(skb, sizeof(struct can_frame)), &cf, sizeof(struct can_frame)); -- cgit v1.2.3 From a2e78cf7a3f562edca4230b188c8832b6214eccd Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Sat, 11 Jul 2015 21:16:08 +0200 Subject: can: slcan: don't touch skb after netif_rx_ni() There is no guarantee that the skb is in the same state after calling net_receive_skb() or netif_rx(). It might be freed or reused. Not really harmful as its a read access, except you turn on the proper debugging options which catch a use after free. Cc: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde --- drivers/net/can/slcan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/can/slcan.c') diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c index a23a7af8eb9a..9a3f15cb7ef4 100644 --- a/drivers/net/can/slcan.c +++ b/drivers/net/can/slcan.c @@ -218,10 +218,10 @@ static void slc_bump(struct slcan *sl) memcpy(skb_put(skb, sizeof(struct can_frame)), &cf, sizeof(struct can_frame)); - netif_rx_ni(skb); sl->dev->stats.rx_packets++; sl->dev->stats.rx_bytes += cf.can_dlc; + netif_rx_ni(skb); } /* parse tty input stream */ -- cgit v1.2.3