panic starting sidecar

[sdeoras]

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Overview of the Issue

when trying to test these guidelines on Raspberry PI I run into panic (logs below)

A paragraph or two about the issue you're experiencing.
$ consul -v
Consul 1.4.1-dev
Protocol 2 spoken by default, understands 2 to 3 (agent will automatically use protocol >2 when speaking to compatible agents)

Platform:
Linux rpi0-1 4.9.35+ #1014 Fri Jun 30 14:34:49 BST 2017 armv6l GNU/Linux

Reproduction Steps

panic occurs when starting sidecar

$ consul connect proxy -sidecar-for socat
==> Consul Connect proxy starting...
    Configuration mode: Agent API
        Sidecar for ID: socat
              Proxy ID: socat-sidecar-proxy

==> Log data will now stream in as it occurs:

    2018/12/21 19:11:57 [INFO] Proxy loaded config and ready to serve
    2018/12/21 19:11:57 [INFO] TLS Identity: spiffe://1ca5dde7-b1a4-a05f-6cbf-fd9f97bfd6c5.consul/ns/default/dc/rpi/svc/socat
    2018/12/21 19:11:57 [INFO] TLS Roots   : [Consul CA 7]
    2018/12/21 19:11:57 [INFO] public listener starting on 0.0.0.0:21000
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x11a80]

goroutine 43 [running]:
runtime/internal/atomic.goXadd64(0x44548e4, 0x1, 0x0, 0xe, 0x3b9aca00)
	/usr/local/go/src/runtime/internal/atomic/atomic_arm.go:96 +0x1c
github.com/hashicorp/consul/connect/proxy.(*Listener).trackConn(0x44548c0, 0x45be228)
	/Users/sdeoras/gocode/consul/connect/proxy/listener.go:231 +0x34
github.com/hashicorp/consul/connect/proxy.(*Listener).handleConn(0x44548c0, 0x223d748, 0x40a0000)
	/Users/sdeoras/gocode/consul/connect/proxy/listener.go:170 +0x10c
created by github.com/hashicorp/consul/connect/proxy.(*Listener).Serve
	/Users/sdeoras/gocode/consul/connect/proxy/listener.go:154 +0x124

Steps to reproduce this issue, eg:

Build code from consul v1.4.0 tag for arm6 and arm7
run consul server on arm7 (raspberry pi 3), consul client on arm6 (raspberry pi zero)
follow steps to setup connect for socat: https://learn.hashicorp.com/consul/getting-started/connect#starting-a-connect-unaware-service

Consul info for both Client and Server

Client info

agent:
	check_monitors = 0
	check_ttls = 0
	checks = 2
	services = 2
build:
	prerelease = dev
	revision =
	version = 1.4.1
consul:
	acl = disabled
	known_servers = 1
	server = false
runtime:
	arch = arm
	cpu_count = 1
	goroutines = 70
	max_procs = 1
	os = linux
	version = go1.11.2
serf_lan:
	coordinate_resets = 0
	encrypted = true
	event_queue = 0
	event_time = 2
	failed = 0
	health_score = 0
	intent_queue = 0
	left = 0
	member_time = 2
	members = 2
	query_queue = 0
	query_time = 1

Server info

agent:
	check_monitors = 0
	check_ttls = 0
	checks = 0
	services = 0
build:
	prerelease = dev
	revision =
	version = 1.4.1
consul:
	acl = disabled
	bootstrap = false
	known_datacenters = 1
	leader = true
	leader_addr = 192.168.1.2:8300
	server = true
raft:
	applied_index = 69
	commit_index = 69
	fsm_pending = 0
	last_contact = 0
	last_log_index = 69
	last_log_term = 2
	last_snapshot_index = 0
	last_snapshot_term = 0
	latest_configuration = [{Suffrage:Voter ID:a8cdf575-d1c5-13d4-40f6-6e3c53829b69 Address:192.168.1.2:8300}]
	latest_configuration_index = 1
	num_peers = 0
	protocol_version = 3
	protocol_version_max = 3
	protocol_version_min = 0
	snapshot_version_max = 1
	snapshot_version_min = 0
	state = Leader
	term = 2
runtime:
	arch = arm
	cpu_count = 4
	goroutines = 89
	max_procs = 4
	os = linux
	version = go1.11.2
serf_lan:
	coordinate_resets = 0
	encrypted = true
	event_queue = 0
	event_time = 2
	failed = 0
	health_score = 0
	intent_queue = 0
	left = 0
	member_time = 2
	members = 2
	query_queue = 0
	query_time = 1
serf_wan:
	coordinate_resets = 0
	encrypted = true
	event_queue = 0
	event_time = 1
	failed = 0
	health_score = 0
	intent_queue = 0
	left = 0
	member_time = 1
	members = 1
	query_queue = 0
	query_time = 1

Operating system and Environment details

OS, Architecture, and any other information you can provide about the environment.
Server on linux/arm/arm7
Client on linux/arm/arm6

Log Fragments

Include appropriate Client or Server log fragments. If the log is longer than a few dozen lines, please include the URL to the gist of the log instead of posting it in the issue. Use -log-level=TRACE on the client and server to capture the maximum log detail.