Hi Jarno,
2016-12-10, Jarno Rajahalme:
On Dec 9, 2016, at 7:04 AM, Thomas Morin <[email protected]
<mailto:[email protected]>> wrote:
2016-12-09, Thomas Morin:
In the same setup as the one on which the bug was observed, [...]
I was confused, I in fact tested the patch (branch-2.5) on a
/different/ setup as the one on which we hit the bug, using MPLS over
a GRE tunnel port, rather than plain MPLS over an eth port.
Sorry if any confusion arised... I can test on the first setup if
relevant.
Maybe the kernel datapath does not support MPLS over a GRE tunnel
port. Having ‘dmesg’ output for the test run might reveal why the
actions validation fails.
The dmesg output was the following:
[171295.258939] openvswitch: netlink: Flow actions may not be safe on
all matching packets.
I've tested the patch on the platform on which the bug was initially hit
(*not* using MPLS/GRE), and I have the following a few times in the logs
right after I do an "ovs-appctl fdb/flush":
2016-12-13T09:44:08.449Z|00001|dpif(handler68)|WARN|Dropped 3 log
messages in last 1 seconds (most recently, 1 seconds ago) due to
excessive rate
2016-12-13T09:44:08.449Z|00002|dpif(handler68)|WARN|system@ovs-system:
failed to put[create] (Invalid argument)
ufid:f046c4c4-b97f-436d-bd7c-91ed307275ac
recirc_id(0),dp_hash(0/0),skb_priority(0/0),in_port(9),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),eth(src=fa:16:3e:61:c0:b5,dst=00:00:5e:00:43:64),eth_type(0x0800),ipv4(src=10.0.1.29,dst=10.0.0.3,proto=6,tos=0/0xfc,ttl=64,frag=no),tcp(src=54253,dst=8080),tcp_flags(0/0),
actions:set(ipv4(src=10.0.1.29,dst=10.0.0.3,ttl=63)),set(eth(src=b8:2a:72:de:1b:e3,dst=00:17:cb:79:2c:01)),push_mpls(label=433680,tc=0,ttl=63,bos=1,eth_type=0x8847),7,set(eth(src=fa:16:3e:61:c0:b5,dst=00:00:5e:00:43:64)),pop_mpls(eth_type=0x800),set(ipv4(src=10.0.1.29,dst=10.0.0.3,tos=0/0xfc,ttl=64)),push_vlan(vid=1,pcp=0),3,8,pop_vlan,13
And dmesg:
[926833.612372] openvswitch: netlink: Flow actions may not be safe on
all matching packets.
-Thomas
On Dec 1, 2016, at 5:57 PM, Jarno Rajahalme <[email protected]
<mailto:[email protected]>> wrote:
On Nov 30, 2016, at 8:50 PM, Ben Pfaff <[email protected]
<mailto:[email protected]>> wrote:
On Wed, Nov 30, 2016 at 06:58:57PM -0800, Jarno Rajahalme wrote:
On Nov 30, 2016, at 8:41 AM, Ben Pfaff <[email protected]
<mailto:[email protected]>> wrote:
On Wed, Nov 30, 2016 at 12:05:46PM +0100, Thomas Morin wrote:
Hi Ben,
2016-11-30, Ben Pfaff:
Do you have any idea what in your OpenFlow pipeline might do
that,
i.e. is there anything especially tricky in the OpenFlow flows?
Are you willing to show us your OpenFlow flow table?
The setup involves three OVS bridges connected with
patch-ports: br-int --
br-tun -- br-mpls, with the traffic that triggers the assert
being processed
by br-int with a NORMAL action (ie. MAC learning).
The flows in this setup aren't particularly tricky, I think,
although I'm
not sure what qualifies as tricky or non-tricky :)
Anyway, since yesterday I managed to identify the event that
trigger the
assert, by adding more logging before the assert and
displaying the actions
taken:
2016-11-29T14:44:40.126Z|00001|odp_util(revalidator45)|WARN|commit_set_ipv4_action
assert would fail....
2016-11-29T14:44:40.126Z|00002|odp_util(revalidator45)|WARN|
base_flow:
ip,in_port=5,dl_vlan=3,dl_vlan_pcp=0,dl_src=fa:16:3e:33:f7:fe,dl_dst=00:00:5e:00:43:64,nw_src=0.0.0.0,nw_dst=0.0.0.0,nw_proto=0,nw_tos=0,nw_ecn=0,nw_ttl=0
2016-11-29T14:44:40.126Z|00003|odp_util(revalidator45)|WARN|
flow:
tcp,in_port=5,dl_vlan=3,dl_vlan_pcp=0,dl_src=fa:16:3e:33:f7:fe,dl_dst=00:00:5e:00:43:64,nw_src=10.0.1.22,nw_dst=10.0.0.3,nw_tos=0,nw_ecn=0,nw_ttl=64,tp_src=53295,tp_dst=8080,tcp_flags=psh|ack
2016-11-29T14:44:40.126Z|00004|odp_util(revalidator45)|WARN|
masks:
recirc_id=0xffffffff,reg0=0xffffffff,in_port=4294967295,dl_vlan=4095,dl_vlan_pcp=7,dl_src=ff:ff:ff:ff:ff:ff,dl_dst=ff:ff:ff:ff:ff:ff,dl_type=0xffff
2016-11-29T14:44:40.126Z|00005|odp_util(revalidator45)|WARN|
actions:
set(ipv4(src=10.0.1.22,dst=10.0.0.3,ttl=63)),set(eth(src=b8:2a:72:de:1b:e3,dst=00:17:cb:79:2c:01)),push_mpls(label=410384,tc=0,ttl=63,bos=1,eth_type=0x8847),9,set(eth(src=fa:16:3e:33:f7:fe,dst=00:00:5e:00:43:64)),pop_mpls(eth_type=0x800),push_vlan(vid=3,pcp=0),1
push_mpls clears L3/L4, while pop_mpls re-populates them, and
then processing the output to port 1 hits the assert?
That's what I'm thinking too.
Jarno, is this something you have time to look into? It'd be
great, if
you do. I'm way behind.
I’m looking at this.
Based on the trace given it seems that:
1. Packet is received on br-int port 32, which outputs it via
NORMAL action over a patch port to another bridge. The only
patch-port on br-int is 2 (patch-tun). The NORMAL action adds
dl_vlan=1.
2. br-tun receives the packet on in_port 1 (patch-int), and
outputs it on it’s port 2 (patch-to-mpls)
3. br-mpls receives the packet on it’s in_port 2 (patch-to-tun),
does pop_vlan, and outputs to it’s port 21 (ipvpn-pp-out), which
is also an patch port.
4. br-mpls (?) receives the packet on it’s in_port 20
(ipvpn-pp-in), does
dec_ttl,push_mpls:0x8847,load:0x644c0->OXM_OF_MPLS_LABEL[],set_field:b8:2a:72:de:1b:e3->eth_src,set_field:00:17:cb:79:2c:01->eth_dst,output:1
All this generates a megaflow:
set(ipv4(src=10.0.1.23,dst=10.0.0.3,ttl=63)),set(eth(src=b8:2a:72:de:1b:e3,dst=00:17:cb:79:2c:01)),push_mpls(label=410816,tc=0,ttl=63,bos=1,eth_type=0x8847),9
This is only the beginning part of the trouble-some megaflow, in
which br-int sends the packet also to another port (vlan 3), and
as part of that pops the MPLS and restores the original ethernet
addresses. Maybe this would happen with the trace too, if you
flushed MACs before the trace?
The patch ports 21 and 20 appear to be in the same bridge and
patched to each other. Is this the case?
The crashing megaflow has in_port=5,dl_vlan=3. Is this also on br-int?
Also, OVS 2.6 is a little bit less aggressive about avoiding
recirculation after mpls operations, and I’d be interested to know
if your case fails the same way with OVS 2.6?
Thanks,
Jarno
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