Date: Sat, 23 Apr 2022 23:01:47 -0800 From: Rob Wing <rob.fx907@gmail.com> To: Eugene Grosbein <eugen@grosbein.net> Cc: Marek Zarychta <zarychtam@plan-b.pwste.edu.pl>, freebsd-hackers@freebsd.org Subject: Re: kernel crash making a vlan on a wlan Message-ID: <CAF3%2Bn_dr1yeZnJkmyn3EBwSPfR%2BvQqT5h%2BtxtWp1=J5t0%2BD2Vg@mail.gmail.com> In-Reply-To: <113d6d4d-eb23-30b1-a9e7-5a82a46604f8@grosbein.net> References: <f08424d6-e209-928b-9927-3cc6c0aabb22@hesiod.org> <421d0c0d-4109-3370-9147-85168051deed@freebsd.org> <9ea3536e-b501-3684-850e-65f95fddf2e7@freebsd.org> <28c9ea32-b913-c153-005b-a62d6a7a6f4e@plan-b.pwste.edu.pl> <113d6d4d-eb23-30b1-a9e7-5a82a46604f8@grosbein.net>
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>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));
}
#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.
>
>
>
>
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<div dir=3D"ltr"><div>From what I can tell, the vlan driver is calling ieee=
80211_output() with the wrong ifnet context and dereferencing a bad pointer=
. <br></div><div><br></div><div>It looks like the passed in if_softc is poi=
nting to a struct ifvlan instead of the expected struct ieee80211_vap</div>=
<div><br></div><div>Looking at vlan_output(), I wonder if the parents ifnet=
context should be used when calling if_output()? something like:</div><div=
><br></div><div>diff --git a/sys/net/if_vlan.c b/sys/net/if_vlan.c<br>index=
2bb5284c2129..5fbd7a79dccc 100644<br>--- a/sys/net/if_vlan.c<br>+++ b/sys/=
net/if_vlan.c<br>@@ -1318,7 +1318,7 @@ vlan_output(struct ifnet *ifp, struc=
t mbuf *m, const struct sockaddr *dst,<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 ifv =3D p->if_softc;<br>=C2=A0 =C2=A0 =C2=A0 =
=C2=A0 } while (p->if_type =3D=3D IFT_L2VLAN);<br><br>- =C2=A0 =C2=A0 =
=C2=A0 return p->if_output(ifp, m, dst, ro);<br>+ =C2=A0 =C2=A0 =C2=A0 r=
eturn ((*p->if_output)(p, m, dst, ro));<br>=C2=A0}<br><br>=C2=A0#ifdef A=
LTQ</div><div><br></div></div><br><div class=3D"gmail_quote"><div dir=3D"lt=
r" class=3D"gmail_attr">On Sat, Apr 23, 2022 at 1:12 PM Eugene Grosbein <=
;<a href=3D"mailto:eugen@grosbein.net" target=3D"_blank">eugen@grosbein.net=
</a>> wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:=
0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">=
24.04.2022 3:28, Marek Zarychta wrote:<br>
<br>
> W dniu 23.04.2022 o 22:11, Craig Leres pisze:<br>
>><br>
>> On 4/23/22 11:12, Craig Leres wrote:<br>
>>> I am able to reproduce the crash with 13.1-RC4.<br>
>><br>
>> I'm also able to reproduce the crash on 12.3-RELEASE-p5. It se=
ems wlan0 is part of the recipe, I tried vlans_em0=3D"vlan0" firs=
t but was not able to induce a crash.<br>
>><br>
>>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 Craig<br>
>><br>
> <br>
> I am curious what is this WiFi hardware that supports 802.1q tagging o=
ver the air? Could you please reveal this?<br>
> <br>
> That's rather not a bug when you are shooting yourself in the foot=
.<br>
<br>
Kernel panic due to ifconfig command is always a bug.<br>
<br>
<br>
<br>
</blockquote></div>
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