Bug in before_validation "[FATAL] failed to allocate memory"

If my model has a before_validation and i call the method "valid?", it returns "[FATAL] failed to allocate memory".
I tested using Ruby 1.8.7 and Ruby 1.9.2

Rails version 3.0.0.rc

Using Ruby 1.9.2

ruby-1.9.2-p0 > a = Project.new(:name => "a")
=> # ruby-1.9.2-p0 > a.valid?
SystemStackError: stack level too deep

from /home/lucas/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/irb/workspace.rb:80

Maybe IRB bug!!
ruby-1.9.2-p0 >

Using Ruby 1.8.7

ruby-1.8.7-p299 > a = Project.new(:name => "a")
=> # ruby-1.8.7-p299 > a.valid?
[FATAL] failed to allocate memory