Kernel.eval("local_variables", binding) in for SEGV in 1.9.1
Howard Yeh showed that the following code causes SEGV in [ruby-core:25634] in ruby 1.9.1 (not in 1.9.2dev):
for i in 1..100
a = 1
The minimum bug reproduction code is
for i in 
p eval('local_variables', binding)
The attached patch solves this problem.