Bug #985: profile lib + iterator => 'NULL pointer given' (ArgumentError)

• Status: Closed
• Assignee: ko1 (Koichi Sasada)
• Target version: 1.9.1 RC2

[brokenoty (Alex Fenton)]

=begin
This simple piece of code works as expected:

iter = 'abc'.each_char
p iter.next
=> "a"

However, if the profile library is required before this (either by -rprofile on the command line or require 'profile') it crashes with an unexpected 'NULL pointer given' error:

ruby -rprofile bug.rb
% cumulative self self total
time seconds seconds calls ms/call ms/call name
0.00 0.00 0.00 2 0.00 0.00 IO#set_encoding
0.00 0.00 0.00 1 0.00 0.00 String#each_char
0.00 0.00 0.00 1 0.00 0.00 Kernel.proc
0.00 0.00 0.00 1 0.00 0.00 Exception#backtrace
0.00 0.00 0.00 1 0.00 0.00 Exception#set_backtrace
0.00 0.01 0.00 1 0.00 10.00 #toplevel
bug.rb:2:in next': NULL pointer given (ArgumentError) from bug.rb:2:in '

Thanks.
=end

[matz (Yukihiro Matsumoto)]

=begin

In message "Re: [ruby-core:21161] [Bug #985] profile lib + iterator => 'NULL pointer given' (ArgumentError)"
on Tue, 6 Jan 2009 08:54:03 +0900, Alex Fenton [e-mail] writes:

|This simple piece of code works as expected:
|
|iter = 'abc'.each_char
|p iter.next
|=> "a"
|
|However, if the profile library is required before this (either by -rprofile on the command line or require 'profile') it crashes with an unexpected 'NULL pointer given' error:
|
|ruby -rprofile bug.rb
| % cumulative self self total
| time seconds seconds calls ms/call ms/call name
| 0.00 0.00 0.00 2 0.00 0.00 IO#set_encoding
| 0.00 0.00 0.00 1 0.00 0.00 String#each_char
| 0.00 0.00 0.00 1 0.00 0.00 Kernel.proc
| 0.00 0.00 0.00 1 0.00 0.00 Exception#backtrace
| 0.00 0.00 0.00 1 0.00 0.00 Exception#set_backtrace
| 0.00 0.01 0.00 1 0.00 10.00 #toplevel
|bug.rb:2:in next': NULL pointer given (ArgumentError) | from bug.rb:2:in '

The direct reason is that rb_sourcefile() returns NULL. The attached
patch will fix the problem, but I am not sure yet why rb_sourcefile()
(and why vm_get_ruby_level_next_cfp) gives us NULL. I hope Koichi has
the answer.

						matz.

--- a/thread.c
+++ b/thread.c
@@ -3545,12 +3545,15 @@ call_trace_proc(VALUE args, int tracing)
{
struct call_trace_func_args *p = (struct call_trace_func_args *)args;
VALUE eventname = rb_str_new2(get_event_name(p->event));

• VALUE filename = rb_str_new2(rb_sourcefile());

• const char *fname = rb_sourcefile();

• VALUE filename;
  VALUE argv[6];
  int line = rb_sourceline();
  ID id = 0;
  VALUE klass = 0;

• if (fname) filename = rb_str_new2(fname);

• else filename = Qnil;
  if (p->event == RUBY_EVENT_C_CALL ||
  p->event == RUBY_EVENT_C_RETURN) {
  id = p->id;
  @@ -3574,7 +3577,7 @@ call_trace_proc(VALUE args, int tracing)
  argv[1] = filename;
  argv[2] = INT2FIX(line);
  argv[3] = id ? ID2SYM(id) : Qnil;

• argv[4] = p->self ? rb_binding_new() : Qnil;

• argv[4] = p->self && fname ? rb_binding_new() : Qnil;
  argv[5] = klass ? klass : Qnil;

  return rb_proc_call_with_block(p->proc, 6, argv, Qnil);

=end

[matz (Yukihiro Matsumoto)]

• Assignee set to ko1 (Koichi Sasada)

=begin

=end

[yugui (Yuki Sonoda)]

• Target version set to 1.9.1 RC2

=begin

=end

[ko1 (Koichi Sasada)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

=begin
Applied in changeset r21578.
=end