Re: [PATCH] net: mac802154: Fix a condition in the receive path

[Stefan Schmidt <stefan@datenfreihafen.org>]

Hello Greg.

On 29.08.22 07:28, Greg KH wrote:
> On Sun, Aug 28, 2022 at 08:16:20PM -0400, Alexander Aring wrote:
>> Hi,
>>
>> On Fri, Aug 26, 2022 at 10:31 AM Miquel Raynal
>> <miquel.raynal@bootlin.com> wrote:
>>>
>>> Upon reception, a packet must be categorized, either it's destination is
>>> the host, or it is another host. A packet with no destination addressing
>>> fields may be valid in two situations:
>>> - the packet has no source field: only ACKs are built like that, we
>>>    consider the host as the destination.
>>> - the packet has a valid source field: it is directed to the PAN
>>>    coordinator, as for know we don't have this information we consider we
>>>    are not the PAN coordinator.
>>>
>>> There was likely a copy/paste error made during a previous cleanup
>>> because the if clause is now containing exactly the same condition as in
>>> the switch case, which can never be true. In the past the destination
>>> address was used in the switch and the source address was used in the
>>> if, which matches what the spec says.
>>>
>>> Cc: stable@vger.kernel.org
>>> Fixes: ae531b9475f6 ("ieee802154: use ieee802154_addr instead of *_sa variants")
>>> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
>>> ---
>>>   net/mac802154/rx.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
>>> index b8ce84618a55..c439125ef2b9 100644
>>> --- a/net/mac802154/rx.c
>>> +++ b/net/mac802154/rx.c
>>> @@ -44,7 +44,7 @@ ieee802154_subif_frame(struct ieee802154_sub_if_data *sdata,
>>>
>>>          switch (mac_cb(skb)->dest.mode) {
>>>          case IEEE802154_ADDR_NONE:
>>> -               if (mac_cb(skb)->dest.mode != IEEE802154_ADDR_NONE)
>>> +               if (hdr->source.mode != IEEE802154_ADDR_NONE)
>>>                          /* FIXME: check if we are PAN coordinator */
>>>                          skb->pkt_type = PACKET_OTHERHOST;
>>>                  else
>>
>>
>> This patch looks okay but it should not be addressed to stable. Leave
>> of course the fixes tag.
> 
> Why do that?  Do you not want this in the stable tree?

We want and we will leave the cc to stable in place, see below.

>> Wpan sends pull requests to net and they have their own way to get
>> into the stable tree when they are in net.
> 
> No, the normal method has been used for quite a while now.

I think Alex was refering to the times where netdev core changes have 
been brought to stable via a different route by DaveM.

This was never the case for ieee802154 though. We are such a small 
subsystem with little traffic that we followed the normal stable process 
and our patches ahve always been picked up by Sasha and the bots.

I will take this through my tree with stable cc and fixes tag preserved 
and it will go to Linux via net and follow the normal process.

regards
Stefan Schmidt