eliminate AddConnection/RemoveConnection race #530
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We were invoking AddConnection in a separate goroutine, and this could result in RemoveConnection getting invoked first, resulting in bogus entries in our connection map, which would effectively prevent connectivity to the other peer until the stale entry got removed through a lost tie break. And if, per chance, the remote end ran into exactly the same race condition, then connectivity between that peer and ourself was broken permanently. Hitting this race condition required a combination of a) no UDP heartbeat being received for HeartbeatTimeout(30s) - this causes the actorLoop to terminate and RemoveConnection to be invoked, and b) the AddConnection invocation getting delayed for at least that long.
bboreham
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Apr 9, 2015
…_race Very subtle, but it looks ok to me. Fixes #529
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We were invoking AddConnection in a separate goroutine, and this could result in RemoveConnection getting invoked first, resulting in bogus entries in our connection map, which would effectively prevent
connectivity to the other peer until the stale entry got removed through a lost tie break. And if, per chance, the remote end ran into exactly the same race condition, then connectivity between that peer and ourself was broken permanently.
Hitting this race condition required a combination of a) no UDP heartbeat being received for HeartbeatTimeout(30s) - this causes the actorLoop to terminate and RemoveConnection to be invoked, and b) the AddConnection invocation getting delayed for at least that long.
Fixes #529.