Bug #20393: `after_fork_ruby` clears all pending interrupts for both parent and child process. - Ruby master - Ruby Issue Tracking System

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Bug #20393

closed

`after_fork_ruby` clears all pending interrupts for both parent and child process.

Added by ioquatix (Samuel Williams) about 1 month ago. Updated about 1 month ago.

Status:

Closed

Assignee:

ioquatix (Samuel Williams)

Target version:

ruby -v:

Backport:

3.0: REQUIRED, 3.1: REQUIRED, 3.2: REQUIRED, 3.3: REQUIRED

[ruby-core:117321]

Description

In the following program, the behaviour of the parent process is affected by whether Process.fork is invoked or not.

Thread.handle_interrupt(RuntimeError => :never) do
  Thread.current.raise(RuntimeError, "Queued error")
  
  puts "Pending interrupt: #{Thread.pending_interrupt?}" # true
  
  pid = Process.fork do
    puts "Pending interrupt (child process): #{Thread.pending_interrupt?}"
    Thread.handle_interrupt(RuntimeError => :immediate){}
  end
  
  _, status = Process.waitpid2(pid)
  puts "Child process status: #{status.inspect}"
  
  puts "Pending interrupt: #{Thread.pending_interrupt?}" # false
end

puts "Exiting..."

I don't think the parent process pending interrupts should be cleared by after_fork_ruby:

static void
after_fork_ruby(rb_pid_t pid)
{
    rb_threadptr_pending_interrupt_clear(GET_THREAD());
    if (pid == 0) {
        // child
        clear_pid_cache();
        rb_thread_atfork();
    }
    else {
        // parent
        after_exec();
    }
}

How about this implementation:

static void
after_fork_ruby(rb_pid_t pid)
{
    if (pid == 0) {
        // child
        rb_threadptr_pending_interrupt_clear(GET_THREAD());
        clear_pid_cache();
        rb_thread_atfork();
    }
    else {
        // parent
        after_exec();
    }
}