Bug #14171: can't alloc thread (ThreadError) in DRbServer#main_loop

• Status: Closed
• Assignee: seki (Masatoshi Seki)
• Target version: 2.5
• ruby -v: ruby 2.5.0dev (2017-12-12 trunk 61147) [x86_64-linux]
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN

[Eregon (Benoit Daloze)]

The bug can be reproduced by adding Thread.report_on_exception = true at the top of lib/drb/drb.rb.

DRbTests::TestBug4409#test_bug4409#<Thread:0x000055597db83478@ruby/lib/drb/drb.rb:1657 aborting> terminated with exception:
Traceback (most recent call last):
	4: from ruby/lib/drb/drb.rb:1665:in `block in main_loop'
	3: from ruby/lib/drb/drb.rb:1665:in `loop'
	2: from ruby/lib/drb/drb.rb:1679:in `block (2 levels) in main_loop'
	1: from ruby/lib/drb/drb.rb:1677:in `ensure in block (2 levels) in main_loop'
ruby/lib/drb/drb.rb:1677:in `new': can't alloc thread (ThreadError)

This Thread.new fails:

if Thread.current['DRb']['stop_service']
  Thread.new { stop_service }
end

I think we don't need an extra Thread to stop the DRbServer.
We just need to tweak the logic in DRbServer#stop_service.

Proposed patch attached.
I need to commit it soon to avoid hundreds of warnings during make test-all for #14143.

@seki (Masatoshi Seki) Could you review?

[Eregon (Benoit Daloze)]

• Target version set to 2.5

[Eregon (Benoit Daloze)]

• Status changed from Open to Closed

Applied in changeset trunk|r61184.

---

Avoid creating a Thread for shutting down a DRbServer

• lib/drb/drb.rb: avoid creating a Thread and call the shutdown logic
  directly. Do not try to kill or join the current Thread.
  Thread.new { stop_service } caused "can't alloc thread (ThreadError)",
  which is shown with Thread.report_on_exception = true.
  [Bug #14171]

[Eregon (Benoit Daloze)]

I also applied @seki's fix in r61342.