Bug #18060: Infinite loop when b_return TracePoint raises

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN

[alanwu (Alan Wu)]

The following program loops indefinitely:

puts("PID: #{$$}")

class Foo
  define_singleton_method(:foo) { return }
end

counter = 0
TracePoint.trace(:b_return) do |tp|
  $stdout.write(counter, ' ', tp.inspect, "\r")
  counter += 1
  raise
end

Foo.foo

It doesn't seem intentional that this loops.

Fix: https://github.com/ruby/ruby/pull/4638

[alanwu (Alan Wu)]

• Description updated (diff)

[alanwu (Alan Wu)]

• Status changed from Open to Closed

Applied in changeset git|744d17ff6c33b09334508e8110007ea2a82252f5.

---

Fix infinite loop when b_return TracePoint throws

Previously, we didn't pop the frame that runs the TracePoint hook for
b_return events for blocks running as methods (bmethods). In case the
hook raises, that formed an infinite loop during stack unwinding in
hook_before_rewind().

[Bug #18060]