* backport r32768 from trunk.

* vm.c: check if cfp is valid. [Bug #5083] [ruby-dev:44208]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@32769 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Sun Jul 31 11:31:07 2011  Kazuki Tsujimoto  <kazuki@callcc.net>
+
+	* backport r32768 from trunk.
+
+	* vm.c: check if cfp is valid. [Bug #5083] [ruby-dev:44208]
+
 Sat Jul 31 01:23:45 2011  Kenta Murata  <mrkn@mrkn.jp>
 
 	* backport r32762 from trunk.

test/ruby/test_thread.rb

@@ -604,6 +604,18 @@ class << Thread.current
       end
     INPUT
   end
+
+  def test_no_valid_cfp
+    bug5083 = '[ruby-dev:44208]'
+    error = assert_raise(RuntimeError) do
+      Thread.new(&Module.method(:nesting)).join
+    end
+    assert_equal("Can't call on top of Fiber or Thread", error.message, bug5083)
+    error = assert_raise(RuntimeError) do
+      Thread.new(:to_s, &Module.method(:undef_method)).join
+    end
+    assert_equal("Can't call on top of Fiber or Thread", error.message, bug5083)
+  end
 end
 
 class TestThreadGroup < Test::Unit::TestCase

vm.c

@@ -854,6 +854,10 @@ rb_vm_cref(void)
 {
     rb_thread_t *th = GET_THREAD();
     rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);
+
+    if (cfp == 0) {
+	rb_raise(rb_eRuntimeError, "Can't call on top of Fiber or Thread");
+    }
     return vm_get_cref(cfp->iseq, cfp->lfp, cfp->dfp);
 }
 
@@ -875,6 +879,9 @@ rb_vm_cbase(void)
     rb_thread_t *th = GET_THREAD();
     rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);
 
+    if (cfp == 0) {
+	rb_raise(rb_eRuntimeError, "Can't call on top of Fiber or Thread");
+    }
     return vm_get_cbase(cfp->iseq, cfp->lfp, cfp->dfp);
 }
 
@@ -1971,6 +1978,10 @@ m_core_set_postexe(VALUE self, VALUE iseqval)
 	rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);
 	VALUE proc;
 
+	if (cfp == 0) {
+	    rb_bug("m_core_set_postexe: unreachable");
+	}
+
 	GetISeqPtr(iseqval, blockiseq);
 
 	blockptr = RUBY_VM_GET_BLOCK_PTR_IN_CFP(cfp);