From: Jeff Mitchell <quixoticsycophant@...>
Date: 2004-05-13T04:00:41+09:00
Subject: [BUG] ruby/dl

# dltest.rb

require 'dl/import'

module DLTest
   extend DL::Importable
   dlload "./dltest.so"
   extern "void* dltest_func()"
end

srand(2727)

ptr = DLTest.dltest_func().to_i

puts "[ruby]  got pointer: #{ptr}"

loop {
   DL::PtrData.new(ptr)
}

__END__

# dltest.c

#include <stdio.h>

static const char* data = "konnichiwa" ;

void* dltest_func()
{
    printf("[C] sending pointer: %d\n", (unsigned int)data) ;
    return (void*)data ;
}

# Makefile

all : dltest.so

dltest.so : dltest.o
	gcc -shared -Wall dltest.o -o dltest.so

dltest.o : dltest.c
	gcc -c -fpic -Wall dltest.c -o dltest.o

clean :
	rm -f dltest.o dltest.so

run : dltest.so
	ruby -w dltest.rb

.PHONY: all clean run

--------------------------------------------------
output:
[C] sending pointer: 1073911707
[ruby]  got pointer: 1073911707
dltest.rb:18: [BUG] Segmentation fault
ruby 1.9.0 (2004-05-12) [i686-linux]
--------------------------------------------------

Same result for ruby-1.8.1 and cvs up -r ruby_1_8.

For me, the segfault occurs on the 3737th iteration.  Results may
vary.  Changing the program slightly can make it segfault only within
a certain range, say 5000-8000 iterations, or cause memory to grow
without bound.

A simpler yet unorthodox example is:

require 'dl'
srand(2727)
FOO = "foo"
loop {
   DL::PtrData.new(2*FOO.object_id) ;
}

Thanks to Mauricio for helping to further isolate the bug on
#ruby-lang IRC.



	
		
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