From: noreply@...
Date: 2007-01-22T09:29:25+09:00
Subject: [ ruby-Bugs-8050 ] SystemStackError thrown if ruby_init is called on a longer stack than other ruby functions

Bugs item #8050, was opened at 2007-01-22 13:29
You can respond by visiting: 
http://rubyforge.org/tracker/?func=detail&atid=1698&aid=8050&group_id=426

Category: Core
Group: 1.8.x
Status: Open
Resolution: None
Priority: 3
Submitted By: Keith Bauer (onesadcookie)
Assigned to: Nobody (None)
Summary: SystemStackError thrown if ruby_init is called on a longer stack than other ruby functions

Initial Comment:
Affects all OSes other than Windows, I believe.

In gc.c's Init_stack, Ruby approximates the stack start as the frame address of ruby_init.  Later, when checking for stack overflows, it subtracts the address of the current frame from the stack start.  That means that if ruby_init is called from a deep stack, and functions that run ruby code are called from relatively shallower stacks, it can get a negative number, which it treats as a very large unsigned number, and thinks the stack has overflowed.

I've attached a patch which finds the correct stack start on Mac OS X and Linux.

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You can respond by visiting: 
http://rubyforge.org/tracker/?func=detail&atid=1698&aid=8050&group_id=426