Bug #15021: Segfault when compiling certain code on Ruby 2.5.1

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: 2.5.1
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN

[st0012 (Stan Lo)]

Steps to reproduce

save the following code to code.rb

code =<<CODE
if false
  new(arg: $arg)
end
CODE

RubyVM::InstructionSequence.compile(code).to_binary

and simply run ruby foo.rb then you'll get

code.rb:7: [BUG] Segmentation fault at 0x0000000000000000
ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin18]

-- Crash Report log information --------------------------------------------
   See Crash Report log file under the one of following:
     * ~/Library/Logs/DiagnosticReports
     * /Library/Logs/DiagnosticReports
   for more details.
Don't forget to include the above Crash Report log file in bug reports.

-- Control frame information -----------------------------------------------
c:0003 p:---- s:0011 e:000010 CFUNC  :to_binary
c:0002 p:0021 s:0007 E:000d28 EVAL   code.rb:7 [FINISH]
c:0001 p:0000 s:0003 E:001c60 (none) [FINISH]

-- Ruby level backtrace information ----------------------------------------
code.rb:7:in `<main>'
code.rb:7:in `to_binary'

-- Machine register context ------------------------------------------------
 rax: 0x00007ffee7896b50 rbx: 0x0000000000000000 rcx: 0x0000000000000000
 rdx: 0x00007ffee7896b60 rdi: 0x00007ffee7896b50 rsi: 0x00007ff0314f65f0
 rbp: 0x00007ffee7896be0 rsp: 0x00007ffee7896b50  r8: 0x0000000000000001
  r9: 0x0000000000000000 r10: 0x0000000000000009 r11: 0x0000000eb63a0560
 r12: 0x000000000000004c r13: 0x00007ff03381c160 r14: 0x0000000000000000
 r15: 0x00007ff0314f6750 rip: 0x00000001083b878e rfl: 0x0000000000010246

-- C level backtrace information -------------------------------------------
0   ruby                                0x0000000108559c77 rb_vm_bugreport + 135
1   ruby                                0x00000001083daa88 rb_bug_context + 472
2   ruby                                0x00000001084caa61 sigsegv + 81
3   libsystem_platform.dylib            0x00007fff5f6fdd7a _sigtramp + 26
4   ruby                                0x00000001083b878e ibf_dump_ci_entries + 270
5   ruby                                0x000000010839f80c ibf_dump_iseq + 828
6   ruby                                0x000000010839f07d iseq_ibf_dump + 397
7   ruby                                0x00000001084274ca iseqw_to_binary + 74
8   ruby                                0x000000010854d214 vm_call_cfunc + 292
9   ruby                                0x0000000108535e01 vm_exec_core + 12785
10  ruby                                0x000000010854792e vm_exec + 142
11  ruby                                0x00000001083e4981 ruby_exec_internal + 177
12  ruby                                0x00000001083e4878 ruby_run_node + 56
13  ruby                                0x0000000108368c1f main + 79

-- Other runtime information -----------------------------------------------

* Loaded script: code.rb

* Loaded features:

    0 enumerator.so
    1 thread.rb
    2 rational.so
    3 complex.so
    4 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/x86_64-darwin18/enc/encdb.bundle
    5 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/x86_64-darwin18/enc/trans/transdb.bundle
    6 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/x86_64-darwin18/rbconfig.rb
    7 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/compatibility.rb
    8 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/defaults.rb
    9 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/deprecate.rb
   10 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/errors.rb
   11 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/version.rb
   12 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/requirement.rb
   13 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/platform.rb
   14 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/basic_specification.rb
   15 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/stub_specification.rb
   16 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/util/list.rb
   17 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/x86_64-darwin18/stringio.bundle
   18 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/rfc2396_parser.rb
   19 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/rfc3986_parser.rb
   20 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/common.rb
   21 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/generic.rb
   22 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/ftp.rb
   23 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/http.rb
   24 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/https.rb
   25 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/ldap.rb
   26 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/ldaps.rb
   27 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri/mailto.rb
   28 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/uri.rb
   29 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/specification.rb
   30 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/exceptions.rb
   31 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_gem.rb
   32 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/monitor.rb
   33 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb
   34 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems.rb
   35 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/dependency.rb
   36 /Users/st0012/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/path_support.rb

[NOTE]
You may have encountered a bug in the Ruby interpreter or extension libraries.
Bug reports are welcome.
For details: http://www.ruby-lang.org/bugreport.html

[IMPORTANT]
Don't forget to include the Crash Report log file under
DiagnosticReports directory in bug reports.

[1]    77987 abort      ruby code.rb

Experimented Platform and Versions

• ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin18]
• ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux-gnu]

[st0012 (Stan Lo)]

Sorry there's a small typo. The command to run the script is ruby code.rb not ruby foo.rb

[shyouhei (Shyouhei Urabe)]

Can reproduce this on 2.5, but not on trunk. Seems 2.5 needs a backport?
Not sure which is the exact revision though.

[rafaelfranca (Rafael França)]

I think this is duplicate of https://bugs.ruby-lang.org/issues/14897 which contain the fix and the backport request tags.

[jeremyevans0 (Jeremy Evans)]

• Is duplicate of Bug #14897: Unexpected behavior of `if` in specific code added

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed