[ovs-dev] [PATCH] connmgr: Fix vswitchd abort when a port is added and the controller is down

[Eelco Chaudron]

On 17 Oct 2018, at 14:03, nusiddiq at redhat.com wrote:

> From: Numan Siddique <nusiddiq at redhat.com>
>
> We see the below trace when a port is added to a bridge and the 
> configured
> controller is down
>
> 0x00007fb002f8b207 in raise () from /lib64/libc.so.6
> 0x00007fb002f8c8f8 in abort () from /lib64/libc.so.6
> 0x00007fb004953026 in ofputil_protocol_to_ofp_version () from 
> /lib64/libopenvswitch-2.10.so.0
> 0x00007fb00494e38e in ofputil_encode_port_status () from 
> /lib64/libopenvswitch-2.10.so.0
> 0x00007fb004ef1c5b in connmgr_send_port_status () from 
> /lib64/libofproto-2.10.so.0
> 0x00007fb004efa9f4 in ofport_install () from 
> /lib64/libofproto-2.10.so.0
> 0x00007fb004efbfb2 in update_port () from /lib64/libofproto-2.10.so.0
> 0x00007fb004efc7f9 in ofproto_port_add () from 
> /lib64/libofproto-2.10.so.0
> 0x0000556d540a3f95 in bridge_add_ports__ ()
> 0x0000556d540a5a47 in bridge_reconfigure ()
> 0x0000556d540a9199 in bridge_run ()
> 0x0000556d540a02a5 in main ()
>

I have a similar crash with the following backtrace:

#0  0x00007f3c6524b207 in raise () from /lib64/libc.so.6
#1  0x00007f3c6524c8f8 in abort () from /lib64/libc.so.6
#2  0x00007f3c66c06cb7 in ofputil_encode_flow_removed 
(fr=fr at entry=0x7f3c59ff9b80, protocol=<optimized out>)
     at lib/ofp-monitor.c:293
#3  0x00007f3c671b1db3 in connmgr_send_flow_removed 
(mgr=mgr at entry=0x56197f5a4800, fr=fr at entry=0x7f3c59ff9b80)
     at ofproto/connmgr.c:1702
#4  0x00007f3c671b7464 in ofproto_rule_send_removed 
(rule=0x56197f69db80) at ofproto/ofproto.c:5729
#5  0x00007f3c671bdc3d in rule_destroy_cb (rule=0x56197f69db80) at 
ofproto/ofproto.c:2839
#6  0x00007f3c66c1e88e in ovsrcu_call_postponed () at lib/ovs-rcu.c:342
#7  0x00007f3c66c1ea94 in ovsrcu_postpone_thread (arg=<optimized out>) 
at lib/ovs-rcu.c:357
#8  0x00007f3c66c20d2f in ovsthread_wrapper (aux_=<optimized out>) at 
lib/ovs-thread.c:354
#9  0x00007f3c66000dd5 in start_thread () from /lib64/libpthread.so.0
#10 0x00007f3c65313b3d in clone () from /lib64/libc.so.6

> When connmgr detects that the connection to the controller is down, it
> resets the ofconn's protocol to 'OFPUTIL_P_NONE' and that's why we
> see the above abort. This patch fixes the issue by also checking the
> connection status before sending the port status in the
>  connmgr_send_port_status().

Same issue, in my case the connection is in S_BACKOFF state.
>
> The issue can be reproduced by running the test added in this patch
> without the fix.
>
> Signed-off-by: Numan Siddique <nusiddiq at redhat.com>
> ---
>  ofproto/connmgr.c |  3 ++-
>  tests/bridge.at   | 21 +++++++++++++++++++++
>  2 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/ofproto/connmgr.c b/ofproto/connmgr.c
> index f78b4c5ff..02ba75938 100644
> --- a/ofproto/connmgr.c
> +++ b/ofproto/connmgr.c
> @@ -1624,7 +1624,8 @@ connmgr_send_port_status(struct connmgr *mgr, 
> struct ofconn *source,
>      ps.reason = reason;
>      ps.desc = *pp;
>      LIST_FOR_EACH (ofconn, node, &mgr->all_conns) {
> -        if (ofconn_receives_async_msg(ofconn, OAM_PORT_STATUS, 
> reason)) {
> +        if (ofconn_receives_async_msg(ofconn, OAM_PORT_STATUS, 
> reason) &&
> +            rconn_is_connected(ofconn->rconn)) {
>              struct ofpbuf *msg;

I could add a similar fix in connmgr_send_flow_removed(). However, I was 
wondering why this problem is surfacing now, did anything change that 
would start to trigger this issue?

>              /* Before 1.5, OpenFlow specified that OFPT_PORT_MOD 
> should not
> diff --git a/tests/bridge.at b/tests/bridge.at
> index 1c3618563..ee398bdb1 100644
> --- a/tests/bridge.at
> +++ b/tests/bridge.at
> @@ -79,3 +79,24 @@ AT_CHECK([ovs-vsctl --columns=status list 
> controller | dnl
>  OVS_APP_EXIT_AND_WAIT([ovs-vswitchd])
>  OVS_APP_EXIT_AND_WAIT([ovsdb-server])
>  AT_CLEANUP
> +
> +AT_SETUP([bridge - add port after stopping controller])
> +OVS_VSWITCHD_START
> +
> +dnl Start ovs-testcontroller
> +ovs-testcontroller --detach punix:controller 
> --pidfile=ovs-testcontroller.pid
> +OVS_WAIT_UNTIL([test -e controller])
> +
> +AT_CHECK([ovs-vsctl set-controller br0 unix:controller])
> +AT_CHECK([ovs-vsctl add-port br0 p1 -- set Interface p1 
> type=internal], [0], [ignore])
> +AT_CHECK([ovs-appctl -t ovs-vswitchd version], [0], [ignore])
> +
> +# Now kill the ovs-testcontroller
> +kill `cat ovs-testcontroller.pid`
> +OVS_WAIT_UNTIL([! test -e controller])
> +AT_CHECK([ovs-vsctl --no-wait add-port br0 p2 -- set Interface p2 
> type=internal], [0], [ignore])
> +AT_CHECK([ovs-appctl -t ovs-vswitchd version], [0], [ignore])
> +
> +OVS_APP_EXIT_AND_WAIT([ovs-vswitchd])
> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> +AT_CLEANUP
> -- 
> 2.17.2
>
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