From 2694585fb38fcb2becaa7c65d8a1ec0b0b320b9b Mon Sep 17 00:00:00 2001 From: KJ Tsanaktsidis Date: Sat, 9 Nov 2024 15:26:53 +1100 Subject: [PATCH] Fix race condition in test_self_stop This test was relying on a sleep to synchronise the parent and child processes. By having the child be the process that stops itself with SIGSTOP, instead of the parent, we can actually properly wait for that using waitpid2 and be notified of the stop. This use of sleep to synchronise processes is potentially flaky and caused failures under rr's `--chaos` mode. --- test/ruby/test_signal.rb | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) diff --git a/test/ruby/test_signal.rb b/test/ruby/test_signal.rb index 7877a35129..a2bdf02b88 100644 --- a/test/ruby/test_signal.rb +++ b/test/ruby/test_signal.rb @@ -310,17 +310,25 @@ class TestSignal < Test::Unit::TestCase end def test_self_stop - assert_ruby_status([], <<-'end;') - begin - fork{ - sleep 1 - Process.kill(:CONT, Process.ppid) - } - Process.kill(:STOP, Process.pid) - rescue NotImplementedError - # ok - end - end; + omit unless Process.respond_to?(:fork) + omit unless defined?(Process::WUNTRACED) + + # Make a process that stops itself + child_pid = fork do + Process.kill(:STOP, Process.pid) + end + + # The parent should be notified about the stop + _, status = Process.waitpid2(child_pid, Process::WUNTRACED) + assert status.stopped? + + # It can be continued + Process.kill(:CONT, child_pid) + + # And the child then runs to completion + _, status = Process.waitpid2(child_pid) + assert status.exited? + assert status.success? end def test_sigwait_fd_unused