Re: vxlan(4) causing splassert when added to a pf(4) queue

[Martin Pieuchot]

Hello Jason,

On 29/11/17(Wed) 12:13, Jason Tubnor wrote:
> On 28 November 2017 at 20:33, Martin Pieuchot <m...@openbsd.org> wrote:
> > Could you do:
> >
> > # sysctl kern.splassert=2
> >
> > And report the tracebacks?
> >
> 
> Hi Martin,
> 
> Please find attached a compressed /var/log/messages file.  This only
> contains data gathered when conducting the iperf tests.  Please advise if
> there are any further tests or data you need.

Here's a diff that should fix the problem, do you confirm?

Index: net/if_vxlan.c
===================================================================
RCS file: /cvs/src/sys/net/if_vxlan.c,v
retrieving revision 1.64
diff -u -p -r1.64 if_vxlan.c
--- net/if_vxlan.c      20 Nov 2017 10:35:24 -0000      1.64
+++ net/if_vxlan.c      14 Dec 2017 11:43:10 -0000
@@ -73,6 +73,8 @@ struct vxlan_softc {
        int64_t                  sc_vnetid;
        u_int8_t                 sc_ttl;
 
+       struct task              sc_sendtask;
+
        LIST_ENTRY(vxlan_softc)  sc_entry;
 };
 
@@ -91,6 +93,7 @@ int    vxlan_output(struct ifnet *, struct
 void    vxlan_addr_change(void *);
 void    vxlan_if_change(void *);
 void    vxlan_link_change(void *);
+void    vxlan_send_dispatch(void *);
 
 int     vxlan_sockaddr_cmp(struct sockaddr *, struct sockaddr *);
 uint16_t vxlan_sockaddr_port(struct sockaddr *);
@@ -135,6 +138,7 @@ vxlan_clone_create(struct if_clone *ifc,
        sc->sc_imo.imo_max_memberships = IP_MIN_MEMBERSHIPS;
        sc->sc_dstport = htons(VXLAN_PORT);
        sc->sc_vnetid = VXLAN_VNI_UNSET;
+       task_set(&sc->sc_sendtask, vxlan_send_dispatch, sc);
 
        ifp = &sc->sc_ac.ac_if;
        snprintf(ifp->if_xname, sizeof ifp->if_xname, "vxlan%d", unit);
@@ -189,6 +193,10 @@ vxlan_clone_destroy(struct ifnet *ifp)
        ifmedia_delete_instance(&sc->sc_media, IFM_INST_ANY);
        ether_ifdetach(ifp);
        if_detach(ifp);
+
+       if (!task_del(net_tq(ifp->if_index), &sc->sc_sendtask))
+               taskq_barrier(net_tq(ifp->if_index));
+
        free(sc->sc_imo.imo_membership, M_IPMOPTS, 0);
        free(sc, M_DEVBUF, sizeof(*sc));
 
@@ -302,8 +310,20 @@ vxlan_multicast_join(struct ifnet *ifp, 
 void
 vxlanstart(struct ifnet *ifp)
 {
+       struct vxlan_softc      *sc = (struct vxlan_softc *)ifp->if_softc;
+
+       task_add(net_tq(ifp->if_index), &sc->sc_sendtask);
+}
+
+void
+vxlan_send_dispatch(void *xsc)
+{
+       struct vxlan_softc      *sc = xsc;
+       struct ifnet            *ifp = &sc->sc_ac.ac_if;
        struct mbuf             *m;
+       struct mbuf_list         ml;
 
+       ml_init(&ml);
        for (;;) {
                IFQ_DEQUEUE(&ifp->if_snd, m);
                if (m == NULL)
@@ -314,9 +334,19 @@ vxlanstart(struct ifnet *ifp)
                        bpf_mtap(ifp->if_bpf, m, BPF_DIRECTION_OUT);
 #endif
 
+               ml_enqueue(&ml, m);
+       }
+
+       if (ml_empty(&ml))
+               return;
+
+       NET_RLOCK();
+       while ((m = ml_dequeue(&ml)) != NULL) {
                vxlan_output(ifp, m);
        }
+       NET_RUNLOCK();
 }
+
 
 int
 vxlan_config(struct ifnet *ifp, struct sockaddr *src, struct sockaddr *dst)