tree 052a67dd3c193f5f64c96826dec51f3a79303291
parent 4288c5a9d81f89f65c02574a434b02e98eea943c
author Christopher Faulet <cfaulet@haproxy.com> 1521191087 +0100
committer Willy Tarreau <w@1wt.eu> 1521195547 +0100
encoding latin1

BUG/MEDIUM: threads/unix: Fix a deadlock when a listener is temporarily disabled

When a listener is temporarily disabled, we start by locking it and then we call
.pause callback of the underlying protocol (tcp/unix). For TCP listeners, this
is not a problem. But listeners bound on an unix socket are in fact closed
instead. So .pause callback relies on unbind_listener function to do its job.

Unfortunatly, unbind_listener hold the listener's lock and then call an internal
function to unbind it. So, there is a deadlock here. This happens during a
reload. To fix the problemn, the function do_unbind_listener, which is lockless,
is now exported and is called when a listener bound on an unix socket is
temporarily disabled.

This patch must be backported in 1.8.