Re: kernel crash making a vlan on a wlan

On Sun, Apr 24, 2022, 8:36 AM Warner Losh <imp@bsdimp.com> wrote:

>
>
> On Sun, Apr 24, 2022, 8:30 AM Rob Wing <rob.fx907@gmail.com> wrote:
>
>> What do you mean when you say they are the same thing?
>>
>
> There is no semantic difference between the two notations. The change will
> have no effect.
>

Oh, I missed the ifp to p change. That will have a big effect.

Warner


> Warner
>
> On Sun, Apr 24, 2022 at 5:35 AM Warner Losh <imp@bsdimp.com> wrote:
>>
>>>
>>>
>>> On Sun, Apr 24, 2022, 1:03 AM Rob Wing <rob.fx907@gmail.com> wrote:
>>>
>>>> From what I can tell, the vlan driver is calling ieee80211_output()
>>>> with the wrong ifnet context and dereferencing a bad pointer.
>>>>
>>>> It looks like the passed in if_softc is pointing to a struct ifvlan
>>>> instead of the expected struct ieee80211_vap
>>>>
>>>> Looking at vlan_output(), I wonder if the parents ifnet context should
>>>> be used when calling if_output()? something like:
>>>>
>>>> diff --git a/sys/net/if_vlan.c b/sys/net/if_vlan.c
>>>> index 2bb5284c2129..5fbd7a79dccc 100644
>>>> --- a/sys/net/if_vlan.c
>>>> +++ b/sys/net/if_vlan.c
>>>> @@ -1318,7 +1318,7 @@ vlan_output(struct ifnet *ifp, struct mbuf *m,
>>>> const struct sockaddr *dst,
>>>>                 ifv = p->if_softc;
>>>>         } while (p->if_type == IFT_L2VLAN);
>>>>
>>>> -       return p->if_output(ifp, m, dst, ro);
>>>> +       return ((*p->if_output)(p, m, dst, ro));
>>>>
>>>
>>> No. Those two are the same thing.
>>>
>>> Warner
>>>
>>>  }
>>>>
>>>>  #ifdef ALTQ
>>>>
>>>>
>>>> On Sat, Apr 23, 2022 at 1:12 PM Eugene Grosbein <eugen@grosbein.net>
>>>> wrote:
>>>>
>>>>> 24.04.2022 3:28, Marek Zarychta wrote:
>>>>>
>>>>> > W dniu 23.04.2022 o 22:11, Craig Leres pisze:
>>>>> >>
>>>>> >> On 4/23/22 11:12, Craig Leres wrote:
>>>>> >>> I am able to reproduce the crash with 13.1-RC4.
>>>>> >>
>>>>> >> I'm also able to reproduce the crash on 12.3-RELEASE-p5. It seems
>>>>> wlan0 is part of the recipe, I tried vlans_em0="vlan0" first but was not
>>>>> able to induce a crash.
>>>>> >>
>>>>> >>          Craig
>>>>> >>
>>>>> >
>>>>> > I am curious what is this WiFi hardware that supports 802.1q tagging
>>>>> over the air? Could you please reveal this?
>>>>> >
>>>>> > That's rather not a bug when you are shooting yourself in the foot.
>>>>>
>>>>> Kernel panic due to ifconfig command is always a bug.
>>>>>
>>>>>
>>>>>
>>>>>