[ovs-dev] [BUG] ovs-ofctl version 2.5.0 will crash with OFPFMFC_BAD_COMMAND

[Samuel Jean]

Hi,

It seems that shelling out to ovs-ofctl very quickly can lead to bug where
it reports an OFPT_ERROR.

We were able to constantly reproduce within minutes of running the above
flow modifications on Unbutu.

Any help, hints or guidance would be appreciated.  I'd be happy to pursue
some debugging that would be required to nail down the issue here.

Best regards,
Sam Jean

# cat ./ofpcrash.sh
#!/bin/sh
ovs-ofctl add-flow br0
'priority=100,table=25,idle_timeout=0,actions=resubmit(,35)' || exit 1
ovs-ofctl add-flow br0
'priority=100,table=35,idle_timeout=0,actions=resubmit(,45)' || exit 1
ovs-ofctl add-flow br0
'priority=100,table=45,idle_timeout=0,actions=resubmit(,50)' || exit 1
ovs-ofctl add-flow br0
'priority=100,table=50,idle_timeout=0,actions=resubmit(,65)' || exit 1
ovs-ofctl add-flow br0
'priority=100,table=65,idle_timeout=0,actions=output:1' || exit 1
ovs-ofctl add-flow br0
'priority=3000,ip,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00,table=0,idle_timeout=0,actions=drop'
|| exit 1
ovs-ofctl add-flow br0
'priority=1000,ip,in_port=1,dl_dst=0c:01:00:12:cf:01,table=0,idle_timeout=0,cookie=20250774994944,actions=resubmit(,25)'
|| exit 1

# while true; do ./ofpcrash.sh || break; done
OFPT_ERROR (xid=0x4): OFPFMFC_BAD_COMMAND
OFPT_FLOW_MOD (xid=0x4):
(***truncated to 64 bytes from 88***)
00000000  01 0e 00 58 00 00 00 04-00 38 20 ff 00 00 00 00 |...X.....8 .....|
00000010  00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 |................|
00000020  00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 |................|
00000030  00 00 00 00 00 00 00 00-32 00 00 00 00 00 00 64 |........2......d|

# ovs-ofctl --version
ovs-ofctl (Open vSwitch) 2.5.0
Compiled Sep 15 2016 12:55:18
OpenFlow versions 0x1:0x4

# uname -srmvp
Linux 3.13.0-100-generic #147-Ubuntu SMP Tue Oct 18 16:48:51 UTC 2016
x86_64 x86_64