Hi, Looks like this bug is caused by violating the fact that if a rule is referenced, the related ofproto should not be destroyed.
If so, I have a patch that also fixes the problem, not sure if this helps. http://patchwork.ozlabs.org/project/openvswitch/patch/[email protected]/ William Tu <[email protected]> 于2021年2月19日周五 上午8:10写道： > > On Wed, Feb 17, 2021 at 1:09 PM Yifeng Sun <[email protected]> wrote: > > > > ovs-vswitchd could crash under these circumstances: > > 1. When one bridge is being destroyed, ofproto_destroy() is called and > > connmgr pointer of its ofproto struct is nullified. This ofproto struct is > > deallocated through 'ovsrcu_postpone(ofproto_destroy_defer__, p);'. > > 2. Before RCU enters quiesce state to actually free this ofproto struct, > > revalidator thread calls udpif_revalidator(), which could handle > > a learn flow and calls ofproto_flow_mod_learn(), it later calls > > ofmonitor_report() and ofproto struct's connmgr pointer is accessed. > > > > The crash stack trace is shown below: > > > > 0 ofmonitor_report (mgr=0x0, rule=rule@entry=0x7fa4ac067c30, > > event=event@entry=NXFME_ADDED, > > reason=reason@entry=OFPRR_IDLE_TIMEOUT, abbrev_ofconn=0x0, > > abbrev_xid=0, old_actions=old_actions@entry=0x0) > > at ofproto/connmgr.c:2160 > > 1 0x00007fa4d6803495 in add_flow_finish (ofproto=0x55d9075d4ab0, > > ofm=<optimized out>, req=req@entry=0x0) > > at ofproto/ofproto.c:5221 > > 2 0x00007fa4d68036af in modify_flows_finish (req=0x0, ofm=0x7fa4980753f0, > > ofproto=0x55d9075d4ab0) > > at ofproto/ofproto.c:5823 > > 3 ofproto_flow_mod_finish (ofproto=0x55d9075d4ab0, > > ofm=ofm@entry=0x7fa4980753f0, req=req@entry=0x0) > > at ofproto/ofproto.c:8088 > > 4 0x00007fa4d680372d in ofproto_flow_mod_learn_finish > > (ofm=ofm@entry=0x7fa4980753f0, > > orig_ofproto=orig_ofproto@entry=0x0) at ofproto/ofproto.c:5439 > > 5 0x00007fa4d68072f9 in ofproto_flow_mod_learn (ofm=0x7fa4980753f0, > > keep_ref=keep_ref@entry=true, > > limit=<optimized out>, below_limitp=below_limitp@entry=0x0) at > > ofproto/ofproto.c:5499 > > 6 0x00007fa4d6835d33 in xlate_push_stats_entry (entry=0x7fa498012448, > > stats=stats@entry=0x7fa4d2701a10, > > offloaded=offloaded@entry=false) at > > ofproto/ofproto-dpif-xlate-cache.c:127 > > 7 0x00007fa4d6835e3a in xlate_push_stats (xcache=<optimized out>, > > stats=stats@entry=0x7fa4d2701a10, > > offloaded=offloaded@entry=false) at > > ofproto/ofproto-dpif-xlate-cache.c:181 > > 8 0x00007fa4d6822046 in revalidate_ukey (udpif=udpif@entry=0x55d90760b240, > > ukey=ukey@entry=0x7fa4b0191660, > > stats=stats@entry=0x7fa4d2705118, > > odp_actions=odp_actions@entry=0x7fa4d2701b50, > > reval_seq=reval_seq@entry=5655486242, > > recircs=recircs@entry=0x7fa4d2701b40, offloaded=false) > > at ofproto/ofproto-dpif-upcall.c:2294 > > 9 0x00007fa4d6825aee in revalidate (revalidator=0x55d90769dd00) at > > ofproto/ofproto-dpif-upcall.c:2683 > > 10 0x00007fa4d6825cf3 in udpif_revalidator (arg=0x55d90769dd00) at > > ofproto/ofproto-dpif-upcall.c:936 > > 11 0x00007fa4d6259c9f in ovsthread_wrapper (aux_=<optimized out>) at > > lib/ovs-thread.c:423 > > 12 0x00007fa4d582cea5 in start_thread () from /usr/lib64/libpthread.so.0 > > 13 0x00007fa4d504b96d in clone () from /usr/lib64/libc.so.6 > > > > At the time of crash, the involved ofproto was already deallocated: > > > > (gdb) print *ofproto > > $1 = ..., name = 0x55d907602820 "nsx-managed", ..., ports = {..., > > one = 0x0, mask = 63, n = 0}, ..., connmgr = 0x0, ... > > > > This patch fixes it. > > > > VMware-BZ: #2700626 > > Signed-off-by: Yifeng Sun <[email protected]> > > --- > > v1->v2: Add check for ofmonitor_flush, thanks William. > > > > LGTM, thanks. > Acked-by: William Tu < [email protected]> > > CC Ilya and Ben to see if any comments. > > I feel this kind of RCU issue is hard to find out, and > existing tools such as addressSanitizer are usually > not helpful. > > William > > > ofproto/connmgr.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/ofproto/connmgr.c b/ofproto/connmgr.c > > index 9c5c633b4171..fa8f6cd0e83a 100644 > > --- a/ofproto/connmgr.c > > +++ b/ofproto/connmgr.c > > @@ -2140,7 +2140,7 @@ ofmonitor_report(struct connmgr *mgr, struct rule > > *rule, > > const struct rule_actions *old_actions) > > OVS_REQUIRES(ofproto_mutex) > > { > > - if (rule_is_hidden(rule)) { > > + if (!mgr || rule_is_hidden(rule)) { > > return; > > } > > > > @@ -2244,6 +2244,10 @@ ofmonitor_flush(struct connmgr *mgr) > > { > > struct ofconn *ofconn; > > > > + if (!mgr) { > > + return; > > + } > > + > > LIST_FOR_EACH (ofconn, connmgr_node, &mgr->conns) { > > struct rconn_packet_counter *counter = ofconn->monitor_counter; > > > > -- > > 2.7.4 > > > > _______________________________________________ > > 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 -- hepeng _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
