On 2/19/21 3:12 AM, 贺鹏 wrote: > 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]/
There is at least one more problem that is not strictly related but in more or less the same part of the code: https://mail.openvswitch.org/pipermail/ovs-dev/2021-February/380582.html > > 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 > > > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
