This is a note to let you know that I've just added the patch titled

can: af_can: can_rcv(): replace WARN_ONCE by pr_warn_once

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: can-af_can-can_rcv-replace-warn_once-by-pr_warn_once.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 8cb68751c115d176ec851ca56ecfbb411568c9e8 Mon Sep 17 00:00:00 2001

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

From: Marc Kleine-Budde mkl@pengutronix.de

commit 8cb68751c115d176ec851ca56ecfbb411568c9e8 upstream.

If an invalid CAN 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+4386709c0c1284dca827@syzkaller.appspotmail.com Suggested-by: Dmitry Vyukov dvyukov@google.com Acked-by: Oliver Hartkopp socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Oliver Hartkopp socketcan@hartkopp.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/can/af_can.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)

--- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -722,13 +722,12 @@ static int can_rcv(struct sk_buff *skb, if (unlikely(!net_eq(dev_net(dev), &init_net))) goto drop;

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

can_receive(skb, dev); return NET_RX_SUCCESS;

Patches currently in stable-queue which might be from mkl@pengutronix.de are

queue-4.4/can-af_can-canfd_rcv-replace-warn_once-by-pr_warn_once.patch queue-4.4/can-af_can-can_rcv-replace-warn_once-by-pr_warn_once.patch