Date: Sun, 24 Apr 2022 08:36:06 -0600 From: Warner Losh <imp@bsdimp.com> To: Rob Wing <rob.fx907@gmail.com> Cc: Eugene Grosbein <eugen@grosbein.net>, Marek Zarychta <zarychtam@plan-b.pwste.edu.pl>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: kernel crash making a vlan on a wlan Message-ID: <CANCZdfoXepZTpH_bvGkCyL1oSi84JwWYDpX3gsyBXEbbrt7bwQ@mail.gmail.com> In-Reply-To: <CAF3%2Bn_c_3bF4aaBVsLOSJ8GhKmcQjujAC=gAvjjDhDHT%2BmzN8A@mail.gmail.com> 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> <CAF3%2Bn_dr1yeZnJkmyn3EBwSPfR%2BvQqT5h%2BtxtWp1=J5t0%2BD2Vg@mail.gmail.com> <CANCZdfq4W1r2Jd2kSLvdg00ACHqSZYQZJhYPAz77%2BsMBgcSBhw@mail.gmail.com> <CAF3%2Bn_c_3bF4aaBVsLOSJ8GhKmcQjujAC=gAvjjDhDHT%2BmzN8A@mail.gmail.com>
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[-- Attachment #1 --] 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. 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. >>>> >>>> >>>> >>>> [-- Attachment #2 --] <div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Apr 24, 2022, 8:30 AM Rob Wing <<a href="mailto:rob.fx907@gmail.com">rob.fx907@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>What do you mean when you say they are the same thing?</div></div></blockquote></div></div><div dir="auto"><br></div><div dir="auto">There is no semantic difference between the two notations. The change will have no effect.</div><div dir="auto"><br></div><div dir="auto">Warner</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Apr 24, 2022 at 5:35 AM Warner Losh <<a href="mailto:imp@bsdimp.com" target="_blank" rel="noreferrer">imp@bsdimp.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Apr 24, 2022, 1:03 AM Rob Wing <<a href="mailto:rob.fx907@gmail.com" target="_blank" rel="noreferrer">rob.fx907@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>>From what I can tell, the vlan driver is calling ieee80211_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 pointing 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, struct mbuf *m, const struct sockaddr *dst,<br> ifv = p->if_softc;<br> } while (p->if_type == IFT_L2VLAN);<br><br>- return p->if_output(ifp, m, dst, ro);<br>+ return ((*p->if_output)(p, m, dst, ro));<br></div></div></blockquote></div></div><div dir="auto"><br></div><div dir="auto">No. Those two are the same thing.</div><div dir="auto"><br></div><div dir="auto">Warner </div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div> }<br><br> #ifdef ALTQ</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Apr 23, 2022 at 1:12 PM Eugene Grosbein <<a href="mailto:eugen@grosbein.net" rel="noreferrer noreferrer" target="_blank">eugen@grosbein.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="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 seems wlan0 is part of the recipe, I tried vlans_em0="vlan0" first but was not able to induce a crash.<br> >><br> >> Craig<br> >><br> > <br> > I am curious what is this WiFi hardware that supports 802.1q tagging over 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> </blockquote></div></div></div> </blockquote></div> </blockquote></div></div></div>
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