and backported as far as branch-2.8.
On Mon, Oct 15, 2018 at 10:52:06AM -0700, Ben Pfaff wrote: > Thanks, applied to master. > > On Fri, Oct 12, 2018 at 12:25:45PM -0700, Yifeng Sun wrote: > > Looks good to me, thanks. > > > > Reviewed-by: Yifeng Sun <[email protected]> > > > > On Mon, Aug 20, 2018 at 8:26 PM Ben Pfaff <[email protected]> wrote: > > > > > Until now, OVS did multicast snooping outputs holding the read-lock on > > > the mcast_snooping object. This could recurse via a patch port to try to > > > take the write-lock on the same object, which deadlocked. This patch > > > fixes > > > the problem, by releasing the read-lock before doing any outputs. > > > > > > It would probably be better to use RCU for mcast_snooping. That would be > > > a bigger patch and less suitable for backporting. > > > > > > Reported-by: Sameh Elsharkawy > > > Reported-at: https://github.com/openvswitch/ovs-issues/issues/153 > > > Signed-off-by > > > <https://github.com/openvswitch/ovs-issues/issues/153Signed-off-by>: Ben > > > Pfaff <[email protected]> > > > --- > > > ofproto/ofproto-dpif-xlate.c | 102 > > > +++++++++++++++++++++++++++++++++++-------- > > > 1 file changed, 84 insertions(+), 18 deletions(-) > > > > > > diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c > > > index e26f6c8f554a..7701b64a2451 100644 > > > --- a/ofproto/ofproto-dpif-xlate.c > > > +++ b/ofproto/ofproto-dpif-xlate.c > > > @@ -534,6 +534,8 @@ static void do_xlate_actions(const struct ofpact *, > > > size_t ofpacts_len, > > > static void clone_xlate_actions(const struct ofpact *, size_t > > > ofpacts_len, > > > struct xlate_ctx *, bool, bool); > > > static void xlate_normal(struct xlate_ctx *); > > > +static void xlate_normal_flood(struct xlate_ctx *ct, > > > + struct xbundle *in_xbundle, struct xvlan > > > *); > > > static void xlate_table_action(struct xlate_ctx *, ofp_port_t in_port, > > > uint8_t table_id, bool may_packet_in, > > > bool honor_table_miss, bool with_ct_orig, > > > @@ -2690,6 +2692,53 @@ update_mcast_snooping_table(const struct xlate_ctx > > > *ctx, > > > } > > > ovs_rwlock_unlock(&ms->rwlock); > > > } > > > + > > > +/* A list of multicast output ports. > > > + * > > > + * We accumulate output ports and then do all the outputs afterward. It > > > would > > > + * be more natural to do the outputs one at a time as we discover the > > > need for > > > + * each one, but this can cause a deadlock because we need to take the > > > + * mcast_snooping's rwlock for reading to iterate through the port lists > > > and > > > + * doing an output, if it goes to a patch port, can eventually come back > > > to the > > > + * same mcast_snooping and attempt to take the write lock (see > > > + * https://github.com/openvswitch/ovs-issues/issues/153). */ > > > +struct mcast_output { > > > + /* Discrete ports. */ > > > + struct xbundle **xbundles; > > > + size_t n, allocated; > > > + > > > + /* If set, flood to all ports. */ > > > + bool flood; > > > +}; > > > +#define MCAST_OUTPUT_INIT { NULL, 0, 0, false } > > > + > > > +/* Add 'mcast_bundle' to 'out'. */ > > > +static void > > > +mcast_output_add(struct mcast_output *out, struct xbundle *mcast_xbundle) > > > +{ > > > + if (out->n >= out->allocated) { > > > + out->xbundles = x2nrealloc(out->xbundles, &out->allocated, > > > + sizeof *out->xbundles); > > > + } > > > + out->xbundles[out->n++] = mcast_xbundle; > > > +} > > > + > > > +/* Outputs the packet in 'ctx' to all of the output ports in 'out', given > > > input > > > + * bundle 'in_xbundle' and the current 'xvlan'. */ > > > +static void > > > +mcast_output_finish(struct xlate_ctx *ctx, struct mcast_output *out, > > > + struct xbundle *in_xbundle, struct xvlan *xvlan) > > > +{ > > > + if (out->flood) { > > > + xlate_normal_flood(ctx, in_xbundle, xvlan); > > > + } else { > > > + for (size_t i = 0; i < out->n; i++) { > > > + output_normal(ctx, out->xbundles[i], xvlan); > > > + } > > > + } > > > + > > > + free(out->xbundles); > > > +} > > > > > > /* send the packet to ports having the multicast group learned */ > > > static void > > > @@ -2697,7 +2746,7 @@ xlate_normal_mcast_send_group(struct xlate_ctx *ctx, > > > struct mcast_snooping *ms OVS_UNUSED, > > > struct mcast_group *grp, > > > struct xbundle *in_xbundle, > > > - const struct xvlan *xvlan) > > > + struct mcast_output *out) > > > OVS_REQ_RDLOCK(ms->rwlock) > > > { > > > struct mcast_group_bundle *b; > > > @@ -2707,7 +2756,7 @@ xlate_normal_mcast_send_group(struct xlate_ctx *ctx, > > > mcast_xbundle = xbundle_lookup(ctx->xcfg, b->port); > > > if (mcast_xbundle && mcast_xbundle != in_xbundle) { > > > xlate_report(ctx, OFT_DETAIL, "forwarding to mcast group > > > port"); > > > - output_normal(ctx, mcast_xbundle, xvlan); > > > + mcast_output_add(out, mcast_xbundle); > > > } else if (!mcast_xbundle) { > > > xlate_report(ctx, OFT_WARN, > > > "mcast group port is unknown, dropping"); > > > @@ -2723,7 +2772,8 @@ static void > > > xlate_normal_mcast_send_mrouters(struct xlate_ctx *ctx, > > > struct mcast_snooping *ms, > > > struct xbundle *in_xbundle, > > > - const struct xvlan *xvlan) > > > + const struct xvlan *xvlan, > > > + struct mcast_output *out) > > > OVS_REQ_RDLOCK(ms->rwlock) > > > { > > > struct mcast_mrouter_bundle *mrouter; > > > @@ -2734,7 +2784,7 @@ xlate_normal_mcast_send_mrouters(struct xlate_ctx > > > *ctx, > > > if (mcast_xbundle && mcast_xbundle != in_xbundle > > > && mrouter->vlan == xvlan->v[0].vid) { > > > xlate_report(ctx, OFT_DETAIL, "forwarding to mcast router > > > port"); > > > - output_normal(ctx, mcast_xbundle, xvlan); > > > + mcast_output_add(out, mcast_xbundle); > > > } else if (!mcast_xbundle) { > > > xlate_report(ctx, OFT_WARN, > > > "mcast router port is unknown, dropping"); > > > @@ -2753,7 +2803,7 @@ static void > > > xlate_normal_mcast_send_fports(struct xlate_ctx *ctx, > > > struct mcast_snooping *ms, > > > struct xbundle *in_xbundle, > > > - const struct xvlan *xvlan) > > > + struct mcast_output *out) > > > OVS_REQ_RDLOCK(ms->rwlock) > > > { > > > struct mcast_port_bundle *fport; > > > @@ -2763,7 +2813,7 @@ xlate_normal_mcast_send_fports(struct xlate_ctx > > > *ctx, > > > mcast_xbundle = xbundle_lookup(ctx->xcfg, fport->port); > > > if (mcast_xbundle && mcast_xbundle != in_xbundle) { > > > xlate_report(ctx, OFT_DETAIL, "forwarding to mcast flood > > > port"); > > > - output_normal(ctx, mcast_xbundle, xvlan); > > > + mcast_output_add(out, mcast_xbundle); > > > } else if (!mcast_xbundle) { > > > xlate_report(ctx, OFT_WARN, > > > "mcast flood port is unknown, dropping"); > > > @@ -2779,7 +2829,7 @@ static void > > > xlate_normal_mcast_send_rports(struct xlate_ctx *ctx, > > > struct mcast_snooping *ms, > > > struct xbundle *in_xbundle, > > > - const struct xvlan *xvlan) > > > + struct mcast_output *out) > > > OVS_REQ_RDLOCK(ms->rwlock) > > > { > > > struct mcast_port_bundle *rport; > > > @@ -2792,7 +2842,7 @@ xlate_normal_mcast_send_rports(struct xlate_ctx > > > *ctx, > > > && mcast_xbundle->ofbundle != in_xbundle->ofbundle) { > > > xlate_report(ctx, OFT_DETAIL, > > > "forwarding report to mcast flagged port"); > > > - output_normal(ctx, mcast_xbundle, xvlan); > > > + mcast_output_add(out, mcast_xbundle); > > > } else if (!mcast_xbundle) { > > > xlate_report(ctx, OFT_WARN, > > > "mcast port is unknown, dropping the report"); > > > @@ -2944,8 +2994,11 @@ xlate_normal(struct xlate_ctx *ctx) > > > } > > > > > > if (mcast_snooping_is_membership(flow->tp_src)) { > > > + struct mcast_output out = MCAST_OUTPUT_INIT; > > > + > > > ovs_rwlock_rdlock(&ms->rwlock); > > > - xlate_normal_mcast_send_mrouters(ctx, ms, in_xbundle, > > > &xvlan); > > > + xlate_normal_mcast_send_mrouters(ctx, ms, in_xbundle, > > > &xvlan, > > > + &out); > > > /* RFC4541: section 2.1.1, item 1: A snooping switch > > > should > > > * forward IGMP Membership Reports only to those ports > > > where > > > * multicast routers are attached. Alternatively stated: > > > a > > > @@ -2954,8 +3007,10 @@ xlate_normal(struct xlate_ctx *ctx) > > > * An administrative control may be provided to override > > > this > > > * restriction, allowing the report messages to be > > > flooded to > > > * other ports. */ > > > - xlate_normal_mcast_send_rports(ctx, ms, in_xbundle, > > > &xvlan); > > > + xlate_normal_mcast_send_rports(ctx, ms, in_xbundle, > > > &out); > > > ovs_rwlock_unlock(&ms->rwlock); > > > + > > > + mcast_output_finish(ctx, &out, in_xbundle, &xvlan); > > > } else { > > > xlate_report(ctx, OFT_DETAIL, "multicast traffic, > > > flooding"); > > > xlate_normal_flood(ctx, in_xbundle, &xvlan); > > > @@ -2968,10 +3023,15 @@ xlate_normal(struct xlate_ctx *ctx) > > > in_xbundle, > > > ctx->xin->packet); > > > } > > > if (is_mld_report(flow, wc)) { > > > + struct mcast_output out = MCAST_OUTPUT_INIT; > > > + > > > ovs_rwlock_rdlock(&ms->rwlock); > > > - xlate_normal_mcast_send_mrouters(ctx, ms, in_xbundle, > > > &xvlan); > > > - xlate_normal_mcast_send_rports(ctx, ms, in_xbundle, > > > &xvlan); > > > + xlate_normal_mcast_send_mrouters(ctx, ms, in_xbundle, > > > &xvlan, > > > + &out); > > > + xlate_normal_mcast_send_rports(ctx, ms, in_xbundle, > > > &out); > > > ovs_rwlock_unlock(&ms->rwlock); > > > + > > > + mcast_output_finish(ctx, &out, in_xbundle, &xvlan); > > > } else { > > > xlate_report(ctx, OFT_DETAIL, "MLD query, flooding"); > > > xlate_normal_flood(ctx, in_xbundle, &xvlan); > > > @@ -2989,6 +3049,8 @@ xlate_normal(struct xlate_ctx *ctx) > > > } > > > > > > /* forwarding to group base ports */ > > > + struct mcast_output out = MCAST_OUTPUT_INIT; > > > + > > > ovs_rwlock_rdlock(&ms->rwlock); > > > if (flow->dl_type == htons(ETH_TYPE_IP)) { > > > grp = mcast_snooping_lookup4(ms, flow->nw_dst, vlan); > > > @@ -2996,20 +3058,24 @@ xlate_normal(struct xlate_ctx *ctx) > > > grp = mcast_snooping_lookup(ms, &flow->ipv6_dst, vlan); > > > } > > > if (grp) { > > > - xlate_normal_mcast_send_group(ctx, ms, grp, in_xbundle, > > > &xvlan); > > > - xlate_normal_mcast_send_fports(ctx, ms, in_xbundle, &xvlan); > > > - xlate_normal_mcast_send_mrouters(ctx, ms, in_xbundle, > > > &xvlan); > > > + xlate_normal_mcast_send_group(ctx, ms, grp, in_xbundle, > > > &out); > > > + xlate_normal_mcast_send_fports(ctx, ms, in_xbundle, &out); > > > + xlate_normal_mcast_send_mrouters(ctx, ms, in_xbundle, &xvlan, > > > + &out); > > > } else { > > > if (mcast_snooping_flood_unreg(ms)) { > > > xlate_report(ctx, OFT_DETAIL, > > > "unregistered multicast, flooding"); > > > - xlate_normal_flood(ctx, in_xbundle, &xvlan); > > > + out.flood = true; > > > } else { > > > - xlate_normal_mcast_send_mrouters(ctx, ms, in_xbundle, > > > &xvlan); > > > - xlate_normal_mcast_send_fports(ctx, ms, in_xbundle, > > > &xvlan); > > > + xlate_normal_mcast_send_mrouters(ctx, ms, in_xbundle, > > > &xvlan, > > > + &out); > > > + xlate_normal_mcast_send_fports(ctx, ms, in_xbundle, > > > &out); > > > } > > > } > > > ovs_rwlock_unlock(&ms->rwlock); > > > + > > > + mcast_output_finish(ctx, &out, in_xbundle, &xvlan); > > > } else { > > > ovs_rwlock_rdlock(&ctx->xbridge->ml->rwlock); > > > mac = mac_learning_lookup(ctx->xbridge->ml, flow->dl_dst, vlan); > > > -- > > > 2.16.1 > > > > > > _______________________________________________ > > > dev mailing list > > > [email protected] > > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > > > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
