[PATCH 3.16 219/254] can: af_can: can_rcv(): replace WARN_ONCE by pr_warn_once

Ben Hutchings
2018-02-28T16:20:01Z

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>
[bwh: Backported to 3.16:
- Keep using the 'drop' label, as it has another user
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -719,13 +719,12 @@ 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;