Bug #13605
closedGC bug calling `ObjectSpace.each_object`
Description
This code made Ruby bail out with the message "[BUG] rb_gc_mark(): 0x000000040dc740 is T_NONE":
ObjectSpace.each_object(Module){|m|
next if (to_ignore.include?(m) rescue true)
if m.respond_to?(:instance_methods)
candidates.concat m.instance_methods(false).collect(&:to_s)
end
}
I haven't been able to repro, but it happened building Pry on Travis CI: https://travis-ci.org/pry/pry/jobs/236720971
The relevant logs are attached.
Files
Updated by shyouhei (Shyouhei Urabe) over 7 years ago
What is to_ignore
and candidates
in your script? Is it possible for you to show us a step to reproduce your situation?
Updated by wanabe (_ wanabe) over 7 years ago
- File patch-for-2508d68e.patch patch-for-2508d68e.patch added
- File Dockerfile Dockerfile added
I guess the code snippet is from pry. https://github.com/pry/pry/blob/c18601d6a4ff97d1b6599ccd9ffc8c63b8d8fccb/lib/pry/input_completer.rb#L172
Here are Dockerfile and patch for pry to reproduce the issue.
33 / 100 are aborted on my environment.
Updated by robertgleeson (Robert Gleeson) over 7 years ago
wanabe (_ wanabe) wrote:
I guess the code snippet is from pry. https://github.com/pry/pry/blob/c18601d6a4ff97d1b6599ccd9ffc8c63b8d8fccb/lib/pry/input_completer.rb#L172
Here are Dockerfile and patch for pry to reproduce the issue.
33 / 100 are aborted on my environment.
Thanks wanabe.
shyouhei (Shyouhei Urabe) wrote:
What is
to_ignore
andcandidates
in your script? Is it possible for you to show us a step to reproduce your situation?
Hey Shyouhei,
The segfault happens while running the pry test suite, I guess you can try:
git clone https://github.com/pry/pry.git
cd pry
git checkout -t origin/respond_to-2.4-warnings
bundle
bundle exec rake
On Linux/Travis it happens all the time, on OSX it happens randomly but this script always reproduces the issue for me, usually on 3rd or 4th attempt:
begin
system "bundle exec rake"
end while $?.exitstatus == 0
I tried a workaround, by moving .collect(&:to_s) underneath candidates.sort!(..) but the bug just happens somewhere else then:
/Users/robert/pry/lib/pry/slop/option.rb:92: [BUG] rb_gc_mark(): 0x007f85ab35dc10 is T_NONE
ruby 2.4.1p111
c:0053 p:---- s:0277 e:000276 CFUNC :to_s
c:0052 p:0016 s:0273 e:000272 METHOD /Users/r/pry/lib/pry/slop/option.rb:92
A very similar segfault happens on ruby-head, here's the build log:
https://travis-ci.org/pry/pry/jobs/239070625
So I think it's an issue since 2.4 and on ruby HEAD as well.
Updated by robertgleeson (Robert Gleeson) over 7 years ago
Another case:
Ruby v2.4.1 (ruby), Pry v0.10.4, method_source v0.8.2, CodeRay v1.1.1, Pry::Slop v3.4.0
/home/travis/build/pry/pry/spec/pry_output_spec.rb:119: warning: assigned but unused variable - custom_io
......................................................................................................................................................................................................................................./home/travis/build/pry/pry/lib/pry/pry_instance.rb:159: [BUG] rb_gc_mark(): 0x00000003556f88 is T_NONE
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]
See: https://travis-ci.org/pry/pry/jobs/239070622
I don't think segv is directly related to Pry::InputCompleter, just luck that it sometimes happens there, sometimes from lib/pry/slop,
and sometimes in pry_instance.rb, something seems wrong in the runtime.
Updated by robertgleeson (Robert Gleeson) over 7 years ago
The segfault no longer happens, since https://github.com/pry/pry/pull/1611/commits/94316852f5c1114f3073876558085835f2cf5377.
if you want to reproduce a commit before that one should work, on the respond_to-2.4-warnings
branch.
Updated by robertgleeson (Robert Gleeson) over 7 years ago
robertgleeson (Robert Gleeson) wrote:
The segfault no longer happens, since https://github.com/pry/pry/pull/1611/commits/94316852f5c1114f3073876558085835f2cf5377.
if you want to reproduce a commit before that one should work, on therespond_to-2.4-warnings
branch.
Spoke too soon, i think we just got lucky, it still happens when i try running the suite many times.
Updated by wanabe (_ wanabe) over 7 years ago
It seems to be for lack of write-barrier. (as _ko1 suggested at https://twitter.com/_ko1/status/871892183464370176)
The following script causes similar [BUG] about 50% of the time.
10000.times do |i|
v = rand(2000)
name = "n#{v}"
value = Object.new
TOPLEVEL_BINDING.local_variable_set name, value
end
It is helpful with "-DRGENGC_CHECK_MODE=2" build flag.
I met following output:
verify_internal_consistency_reachable_i: WB miss (O->Y) 0x000055f470054578 [3LM ] T_IMEMO env -> 0x000055f4701cc770 [0 ] T_OBJECT (Object)
verify_internal_consistency_reachable_i: WB miss (O->Y) 0x000055f470054758 [3LM ] T_IMEMO env -> 0x000055f470206920 [0 ] T_OBJECT (Object)
(snip)
a.rb:3: [BUG] gc_verify_internal_consistency: found internal inconsistency.
ruby 2.5.0dev (2017-06-11 trunk 59060) [x86_64-linux]
(snip)
Updated by ko1 (Koichi Sasada) over 7 years ago
- Status changed from Open to Closed
Applied in changeset trunk|r59063.
-
proc.c (get_local_variable_ptr): return found env ptr. Returned env
will be used by write barrier at `bind_local_variable_set()'.
[Bug #13605] -
test/ruby/test_proc.rb: add a test for this issue.
Updated by wanabe (_ wanabe) over 7 years ago
- Related to Bug #13155: Segfault testing Pry added
Updated by wanabe (_ wanabe) over 7 years ago
- Related to Bug #13537: ruby crash in rb_gc_mark added
Updated by wanabe (_ wanabe) over 7 years ago
git bisect
shows that the issue is come from r55766 [Feature #12628].
This commit is in ruby_2_4, but not in ruby_2_3 / ruby_2_2.
To core team:
Would you please set "Backport" of the ticket to "2.2: DONTNEED, 2.3: DONTNEED, 2.4: REQUIRED"?
Updated by duerst (Martin Dürst) over 7 years ago
- Backport changed from 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN to 2.2: DONTNEED, 2.3: DONTNEED, 2.4: REQUIRED
Updated by nagachika (Tomoyuki Chikanaga) about 7 years ago
- Backport changed from 2.2: DONTNEED, 2.3: DONTNEED, 2.4: REQUIRED to 2.2: DONTNEED, 2.3: DONTNEED, 2.4: DONE
ruby_2_4 r59503 merged revision(s) 59063.