tree b5b31c880921fe9df6fb4f033af8865cb2c42f6b
parent bb35e1f5aa69f55f588e060fee6098db37abe94c
author Willy Tarreau <w@1wt.eu> 1674124461 +0100
committer Willy Tarreau <w@1wt.eu> 1674124461 +0100
encoding latin1

BUG/MINOR: listener: close tiny race between resume_listener() and stopping

Pierre Cheynier reported a very rare race condition on soft-stop in the
listeners. What happens is that if a previously limited listener is
being resumed by another thread finishing an accept loop, and at the
same time a soft-stop is performed, the soft-stop will turn the
listener's state to LI_INIT, and once the listener's lock is released,
resume_listener() in the second thread will try to resume this listener
which has an fd==-1, yielding a crash in listener_set_state():

  FATAL: bug condition "l->rx.fd == -1" matched at src/listener.c:288

The reason is that resume_listener() only checks for LI_READY, but doesn't
consider being called with a non-initialized or a stopped listener. Let's
also make sure we don't try to ressuscitate such a listener there.

This will have to be backported to all versions.