Patch "can: af_can: can_rcv(): replace WARN_ONCE by pr_warn_once" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

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 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

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-4.14 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/can/af_can.c |   18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -721,20 +721,16 @@ static int can_rcv(struct sk_buff *skb,
 {
 	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 
-	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))
-		goto drop;
+	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);
+		kfree_skb(skb);
+		return NET_RX_DROP;
+	}
 
 	can_receive(skb, dev);
 	return NET_RX_SUCCESS;
-
-drop:
-	kfree_skb(skb);
-	return NET_RX_DROP;
 }
 
 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,


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

queue-4.14/can-af_can-canfd_rcv-replace-warn_once-by-pr_warn_once.patch
queue-4.14/can-af_can-can_rcv-replace-warn_once-by-pr_warn_once.patch
queue-4.14/can-peak-fix-potential-bug-in-packet-fragmentation.patch