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Bug #13632

closed

Not processable interrupt queue for a thread after it's notified that FD is closed in some other thread.

Added by nvashchenko (Nikolay Vashchenko) over 7 years ago. Updated over 7 years ago.

Status:
Closed
Assignee:
-
Target version:
-
ruby -v:
2.2.x, 2.3.x, 2.4.x, 2.5.x
Backport:
2.2: UNKNOWN, 2.3: DONE, 2.4: DONE
[ruby-core:81581]

Description

In the bugfix for https://bugs.ruby-lang.org/issues/13076 has been introduced another bug, caused by a busy waiting in rb_notify_fd_close method, while the FD is being released. During this waiting, it pumps huge amounts of the ruby_error_stream_closed errors into thread's interrupt queue, which almost all stay there unprocessed. It can be up for several hundred of exceptions in the queue, depending on circumstances.

  a = []
  t = []
  10.times do
    r,w = IO.pipe
    a << [r,w]
    t << Thread.new do
      while r.gets
      end rescue IOError
      # Interrupt queue is full and all IO is broken
     Thread.current.pending_interrupt? # Expected to be false, because it's already rescued
      IO.sysopen ("/dev/tty")                   # Expected not to throw an error. On each such call, it dequeues the next item from interrupt queue until there's none
    end
  end
  a.each do |r,w|
    w.puts "test"
    w.close
    r.close
  end
  t.each do |th|
    th.join
  end

Output:

Traceback (most recent call last):
	1: from test2.rb:9:in `block (2 levels) in <main>'
test2.rb:9:in `sysopen': stream closed in another thread (IOError)
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