arcnet: protocol is buggy messages in 3.0 kernel, not in 2.33 kernel

arcnet: protocol is buggy messages in 3.0 kernel, not in 2.33 kernel

[Rob Janssen]

Hello all

Since we've moved from the 2.33 kernel to the 3.0 kernel, we see the
following kernel messages in dmesg:

protocol 001a is buggy, dev arc0 skb=c702e2f4

The device involved is an arcnet device.
The warning is logged by dev.c, see the following code snippet:

if (skb_network_header(skb2) < skb2->data ||
			    skb2->network_header > skb2->tail) {
				if (net_ratelimit())
					printk(KERN_CRIT "protocol %04x is "
					       "buggy, dev %s skb=%04x\n",
					       ntohs(skb2->protocol),
					       dev->name, skb_network_header(skb2));
				skb_reset_network_header(skb2);
			}
I added some logging, and it appears that skb2->network_header is
placed in memory beyond skb2->tail (the second check).

Does anyone have what causes this message in the 3.0 kernel and/or how
to fix this ?

Thanks in advance,

Rob Janssen

arcnet: protocol is buggy messages in 3.0 kernel, not in 2.33 kernel

[Rob Janssen]

Hello all

Since we've moved from the 2.33 kernel to the 3.0 kernel, we see the
following kernel messages in dmesg:

protocol 001a is buggy, dev arc0 skb=c702e2f4

The device involved is an arcnet device.
The warning is logged by dev.c, see the following code snippet:

if (skb_network_header(skb2) < skb2->data ||
                           skb2->network_header > skb2->tail) {
                               if (net_ratelimit())
                                       printk(KERN_CRIT "protocol %04x is "
                                              "buggy, dev %s skb=%04x\n",
                                              ntohs(skb2->protocol),
                                              dev->name,
skb_network_header(skb2));
                               skb_reset_network_header(skb2);
                       }
I added some logging, and it appears that skb2->network_header is
placed in memory beyond skb2->tail (the second check).

Does anyone have what causes this message in the 3.0 kernel and/or how
to fix this ?

Thanks in advance,

Rob Janssen

Re: arcnet: protocol is buggy messages in 3.0 kernel, not in 2.33 kernel

[Francois Romieu]

Rob Janssen <rob.janssen76@gmail.com> :
[...]
> Does anyone have what causes this message in the 3.0 kernel and/or how
> to fix this ?

Wild guess: hard_header_len is sizeof(struct archdr). archdr embeds a huge
ethhdr but the header build helper only accounts for ARC_HDR_SIZE +
RFC1201_HDR_SIZE.

-- 
Ueimor

Re: arcnet: protocol is buggy messages in 3.0 kernel, not in 2.33 kernel

[Rob Janssen]

On Fri, May 4, 2012 at 1:23 AM, Francois Romieu <romieu@fr.zoreil.com> wrote:
> Rob Janssen <rob.janssen76@gmail.com> :
> [...]
>> Does anyone have what causes this message in the 3.0 kernel and/or how
>> to fix this ?
>
> Wild guess: hard_header_len is sizeof(struct archdr). archdr embeds a huge
> ethhdr but the header build helper only accounts for ARC_HDR_SIZE +
> RFC1201_HDR_SIZE.
>
> --
> Ueimor

I solved the problem:
The socket was opened with the wrong protocol: ETH_P_ALL instead of
ETH_P_ARCNET.
This causes arcnet messages to be sent to all network devices.
I don't know why older kernel versions didn't complain..

Rob