From: "usa (Usaku NAKAMURA)" <usa@...>
Date: 2012-10-25T10:21:45+09:00
Subject: [ruby-core:48215] [ruby-trunk - Bug #7212][Assigned] "stack level too deep" in Fiber much earlier in new versions of 1.9.3


Issue #7212 has been updated by usa (Usaku NAKAMURA).

Status changed from Open to Assigned
Assignee set to ko1 (Koichi Sasada)


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Bug #7212: "stack level too deep" in Fiber much earlier in new versions of 1.9.3
https://bugs.ruby-lang.org/issues/7212#change-31480

Author: fiddur (Fredrik Liljegren)
Status: Assigned
Priority: Normal
Assignee: ko1 (Koichi Sasada)
Category: 
Target version: 
ruby -v: ruby 1.9.3p286 (2012-10-12 revision 37165) [x86_64-linux] (and others, see description)


I was getting SystemStackError in my application on some servers and not others; on all with 1.9.3-p286 and on some with p194, and on none with 1.9.2-head.  I boiled it down to this:


def recursive(level = 0)
  -> do
    p "In block #{level}"
    if level < 1000
      subblock = recursive(level + 1)
      subblock.call
    end
  end
end

p "Doing recursive call in a fiber"
Fiber.new { recursive.call }.resume


On server A, 1.9.3-p194 and 1.9.3-p286 got up to 11 levels of recursion, while 1.9.2-head got up to 97 levels.
On server B (without 1.9.2), 1.9.3-p194 got 55 levels while p286 still got 11 levels.

I don't know what changes are made, but I think 11 levels are way on the low side for many applications.

(My original problem was with a thin-server running rack-fiber_pool with em-synchrony getting too deep in a regexp in Addressable::URI.)


-- 
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