[PATCH 4.9 08/66] can: af_can: canfd_rcv(): replace WARN_ONCE by pr_warn_once

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>

commit d4689846881d160a4d12a514e991a740bcb5d65a upstream.

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@xxxxxxxxxxxxxxxxxxxxxxxxx
Suggested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Cc: linux-stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 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
@@ -745,13 +745,12 @@ static int canfd_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 != 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))
+	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);
 		goto drop;
+	}
 
 	can_receive(skb, dev);
 	return NET_RX_SUCCESS;