Bug #7180: set_trace_func with error in proc block locks up Ruby with 100% cpu usage and no way to exit without killing proc

• Status: Closed
• Assignee: ko1 (Koichi Sasada)
• Target version: 2.0.0
• ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin11.4.0]

[garysweaver (Gary Weaver)]

Causes 100% cpu usage and cannot ctrl-C to exit (have to kill proc):

set_trace_func proc {|event, file, line, id, binding, classname| raise "error"}

Understand that set_trace_func plays by different rules, but this isn't expected.

[garysweaver (Gary Weaver)]

One workaround:

l = lambda {|event, file, line, id, binding, classname| eval "def invalid syntax"}
set_trace_func proc {|event, file, line, id, binding, classname| begin;l.call(event, file, line, id, binding, classname);rescue SystemExit,Interrupt;raise;rescue Exception;end}

Would it be good to add to the rdoc for set_trace_func to indicate that the user should consider using this method if there is any chance it might raise an Exception other than SystemExit or Interrupt?

[drbrain (Eric Hodel)]

• Category set to core
• Status changed from Open to Feedback

=begin
I can't reproduce this. Can you provide a way to reproduce it?

With trunk:

$ time ruby20 -ve 'set_trace_func proc {|event, file, line, id, binding, classname| raise "error"}; loop do 1 + 1 end'
ruby 2.0.0dev (2012-09-06 trunk 36915) [x86_64-darwin12.1.0]
-e:1:in block in <main>': error (RuntimeError) from -e:1:in '

real 0m0.017s
user 0m0.012s
sys 0m0.004s

With ruby 1.9.4-p194 as you are running:

$ time ruby19 -ve 'set_trace_func proc {|event, file, line, id, binding, classname| raise "error"}; loop do 1 + 1 end'
ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin12.2.0]
-e:1:in block in <main>': error (RuntimeError) from -e:1:in '

real 0m0.017s
user 0m0.012s
sys 0m0.004s

=end

[mame (Yusuke Endoh)]

• Target version set to 2.0.0

Gary Weaver, ping?

--
Yusuke Endoh [e-mail]

[mame (Yusuke Endoh)]

• Priority changed from Normal to 3

[ko1 (Koichi Sasada)]

The following script also repeat "[:return, 1]".
I'm not sure it is same problem or not.

def m
p:m
end

TracePoint.trace(:call, :return){|tp| p [tp.event, tp.line]; raise "bar"}
m

This can be reproduced inside eval:

eval 'set_trace_func proc {|event, file, line, id, binding, classname| raise "error"}'

Edit: It seems this can be repro'd whenever there is a parent control frame.

[ko1 (Koichi Sasada)]

• Status changed from Feedback to Closed
• Assignee set to ko1 (Koichi Sasada)

Maybe r38331 (nobu's commit) solves this issue.