The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d4689846881d160a4d12a514e991a740bcb5d65a Mon Sep 17 00:00:00 2001

From: Marc Kleine-Budde mkl@pengutronix.de Date: Tue, 16 Jan 2018 19:30:14 +0100 Subject: [PATCH] can: af_can: canfd_rcv(): replace WARN_ONCE by pr_warn_once

If an invalid CANFD frame is received, from a driver or from a tun interface, a Kernel warning is generated.

This patch replaces the WARN_ONCE by a simple pr_warn_once, so that a kernel, bootet with panic_on_warn, does not panic. A printk seems to be more appropriate here.

Reported-by: syzbot+e3b775f40babeff6e68b@syzkaller.appspotmail.com Suggested-by: Dmitry Vyukov dvyukov@google.com Acked-by: Oliver Hartkopp socketcan@hartkopp.net Cc: linux-stable stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de

diff --git a/net/can/af_can.c b/net/can/af_can.c index ae835382e678..4d7f988a3130 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -738,20 +738,16 @@ static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, { struct canfd_frame *cfd = (struct canfd_frame *)skb->data;

- if (WARN_ONCE(dev->type != ARPHRD_CAN || - skb->len != CANFD_MTU || - cfd->len > CANFD_MAX_DLEN, - "PF_CAN: dropped non conform CAN FD skbuf: " - "dev type %d, len %d, datalen %d\n", - dev->type, skb->len, cfd->len)) - goto drop; + if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU || + cfd->len > CANFD_MAX_DLEN)) { + pr_warn_once("PF_CAN: dropped non conform CAN FD skbuf: dev type %d, len %d, datalen %d\n", + dev->type, skb->len, cfd->len); + kfree_skb(skb); + return NET_RX_DROP; + }

can_receive(skb, dev); return NET_RX_SUCCESS; - -drop: - kfree_skb(skb); - return NET_RX_DROP; }

/*