Data race related to AutoRelay/AutoNAT

[raulk]

Running tests on CI with -race (#545) uncovered a data race:

=== RUN   TestAutoRelay
==================
WARNING: DATA RACE
Read at 0x00c0000788d8 by goroutine 49:
  github.com/libp2p/go-libp2p-autonat.(*AmbientAutoNAT).Status()
      /home/travis/gopath/pkg/mod/github.com/libp2p/[email protected]/autonat.go:88 +0x3e
  github.com/libp2p/go-libp2p/p2p/host/relay.(*AutoRelayHost).background()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/p2p/host/relay/autorelay.go:98 +0x1ff
Previous write at 0x00c0000788d8 by goroutine 48:
  github.com/libp2p/go-libp2p-autonat.(*AmbientAutoNAT).autodetect()
      /home/travis/gopath/pkg/mod/github.com/libp2p/[email protected]/autonat.go:173 +0x663
  github.com/libp2p/go-libp2p-autonat.(*AmbientAutoNAT).background()
      /home/travis/gopath/pkg/mod/github.com/libp2p/[email protected]/autonat.go:112 +0x148
Goroutine 49 (running) created at:
  github.com/libp2p/go-libp2p/p2p/host/relay.NewAutoRelayHost()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/p2p/host/relay/autorelay.go:71 +0x431
  github.com/libp2p/go-libp2p/config.(*Config).NewNode()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/config/config.go:211 +0xc51
  github.com/libp2p/go-libp2p.NewWithoutDefaults()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/libp2p.go:68 +0x132
  github.com/libp2p/go-libp2p.New()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/libp2p.go:54 +0x12f
  github.com/libp2p/go-libp2p/p2p/host/relay_test.TestAutoRelay()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/p2p/host/relay/autorelay_test.go:150 +0x445
  testing.tRunner()
      /home/travis/.gimme/versions/go1.11.5.linux.amd64/src/testing/testing.go:827 +0x162
Goroutine 48 (running) created at:
  github.com/libp2p/go-libp2p-autonat.NewAutoNAT()
      /home/travis/gopath/pkg/mod/github.com/libp2p/[email protected]/autonat.go:82 +0x1e3
  github.com/libp2p/go-libp2p/p2p/host/relay.NewAutoRelayHost()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/p2p/host/relay/autorelay.go:68 +0x2e5
  github.com/libp2p/go-libp2p/config.(*Config).NewNode()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/config/config.go:211 +0xc51
  github.com/libp2p/go-libp2p.NewWithoutDefaults()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/libp2p.go:68 +0x132
  github.com/libp2p/go-libp2p.New()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/libp2p.go:54 +0x12f
  github.com/libp2p/go-libp2p/p2p/host/relay_test.TestAutoRelay()
      /home/travis/gopath/src/github.com/libp2p/go-libp2p/p2p/host/relay/autorelay_test.go:150 +0x445
  testing.tRunner()
      /home/travis/.gimme/versions/go1.11.5.linux.amd64/src/testing/testing.go:827 +0x162
==================
--- FAIL: TestAutoRelay (5.98s)
    testing.go:771: race detected during execution of test
FAIL

Possibly related to libp2p/go-libp2p-autonat#16.

[vyzo]

What's the race here? It seems that it is on the Status(), which is totally benign.

[vyzo]

This is not a critical bug, a rather benign race that is easily fixed by mutex protecting the boolean access.

[vyzo]

Fixed in libp2p/go-libp2p-autonat#17