Thanks Jesse! I think you may be close, but it is the ovs code that is re-entering it's self, this isn't an arp storm from a circle of traffic path, as far as i can tell. it is an attempt to transmit a single packet.. but never gets even the arp out to the stack at all. you can see build_tunnel_send 3 times as the stack trace goes in the original post. but no packets make it out. the program call stack is 13000 frames deep - which is why it crashed.
any further thoughts? On Tue, Sep 15, 2015 at 7:38 PM, Jesse Gross <[email protected]> wrote: > On Mon, Sep 14, 2015 at 9:57 PM, David Evans <[email protected]> > wrote: > > Hi OVS. > > > > i am using rev 2.3.2+29bae5412ea3c6a1e20d79afd25c11b968dffa05-r0 > > > > As you can see from my gdb backtrace 13K frames deep below we get an arp > > request because build_tunnel_send (frame 13659 below) decided we're > starting > > to use a gre tunnel on a bridge and there's no arp cache for the > destination > > yet. > > > > so what follows is xlate_flood_packet -> ofproto_dpif_execute_actions -> > > xlate_actions -> do_xlate_actions -> xlate_output_action -> flood_packet > > -> compose_output_action -> compose_output_action__ -> > xlate_table_action -> > > xlate_recusively > > -> do_xlate_actions (* a few actions) then we get back to > > compose_output_action__ and build_tunnel_send again. > > > > So infinitely the code will generate arp packets, but never deliver any > of > > the arps out to the linux stack and keeps re-entering till it exhausts > the > > stack > > > > How do i stop this? > > OVS should protect itself better but fundamentally the issue is that > there is a loop somewhere in your configuration. Most likely the > remote_ip on your GRE port is pointing back into br0. Another > possibility is that a patch port is bridging packets between br0 and > breth1. In both of these cases, ARP packets from the IP stack are > re-entering the inside of the tunnel, which causes another ARP packet > and so on. >
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