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 <pkusunyif...@gmail.com> --- ofproto/connmgr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/ofproto/connmgr.c b/ofproto/connmgr.c index 9c5c633b4171..ee07df7a8bc0 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; } -- 2.7.4 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev