Bug #20168: Process won't exit when Ractor.select waiting a Ractor

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: 3.3.0
• Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

[shia (Sangyong Sim)]

Reproduction code

trap(:INT) do
  puts "SIGINT"
  exit
end

trap(:TERM) do
  puts "SIGTERM"
  exit
end

r = Ractor.new do
  loop do
    sleep 1
  end
end

Ractor.select(r) # stucked.
# SIGINT/SIGTERM sent to Ruby process(confirmed by trap),
# but process won't exit.

Expected behavior

Process killed successfully with exit code 0.

Affected Ruby version

3.3.0
3.2.x works as expected.

[luke-gru (Luke Gruber)]

Patch here: https://github.com/ruby/ruby/pull/9492

[[e-mail] (Masato Ohba)]

I think I have encountered the same issue. I was able to reproduce the problem using a simpler code that results in a process hang when a Ractor, which internally raises an exception, is passed to Ractor.select.

Here is the minimal code snippet that demonstrates the issue:

ruby -e "r = Ractor.new{1/0}; Ractor.select(*[r])"

Notably, when I built Ruby using the branch from https://github.com/ruby/ruby/pull/9492, the issue did not occur. It appears that the changes in this branch might contain a fix or alter the behavior to prevent the hang.