Issue #14421 has been updated by nagachika (Tomoyuki Chikanaga).

Backport changed from 2.3: REQUIRED, 2.4: REQUIRED, 2.5: DONE to 2.3: REQUIRED, 2.4: DONE, 2.5: DONE

ruby_2_4 r62866 merged revision(s) 62115.

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Bug #14421: super_method segfaults when called on a re-bound Method
https://bugs.ruby-lang.org/issues/14421#change-71128

* Author: rusterholz (Andy Rusterholz)
* Status: Closed
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-darwin17]
* Backport: 2.3: REQUIRED, 2.4: DONE, 2.5: DONE
----------------------------------------
The line of code below causes a segfault on 2.5.0.

This appears to possibly be related to #[[11419]], but is not the same.

The segfault is not limited to the String class used in the example; it can be reproduced with any class with at least one instance_method. More generally, it can be reproduced any time `super_method` is called on a Method which was formed by (validly) calling `bind` on an UnboundMethod.

~~~
$ ruby -e 'String.instance_method(:length).bind(String.new).super_method'
-e:1: [BUG] Segmentation fault at 0x0000000000000018
ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-darwin17]

-- 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:0010 e:000009 CFUNC  :super_method
c:0002 p:0028 s:0006 e:000005 EVAL   -e:1 [FINISH]
c:0001 p:0000 s:0003 E:001570 (none) [FINISH]

-- Ruby level backtrace information ----------------------------------------
-e:1:in `<main>'
-e:1:in `super_method'

-- Machine register context ------------------------------------------------
 rax: 0x0000000000000000 rbx: 0x00007fc51f43e1e0 rcx: 0x0000000108308730
 rdx: 0x0000000000000000 rdi: 0x00007fc52106fd18 rsi: 0x0000000108308730
 rbp: 0x00007ffee7b78f80 rsp: 0x00007ffee7b78f40  r8: 0x00007fc51f4623b8
  r9: 0x0000000108543fa0 r10: 0x00007fc51f5070e8 r11: 0x0000000000000016
 r12: 0x0000000000000000 r13: 0x00007fc51f541860 r14: 0x0000000000000000
 r15: 0x00007fc52106fd18 rip: 0x000000010819a2eb rfl: 0x0000000000010246

-- C level backtrace information -------------------------------------------
0   libruby.2.5.dylib                   0x0000000108274d17 rb_vm_bugreport + 135
1   libruby.2.5.dylib                   0x00000001080f9988 rb_bug_context + 472
2   libruby.2.5.dylib                   0x00000001081e9161 sigsegv + 81
3   libsystem_platform.dylib            0x00007fff7e2c0f5a _sigtramp + 26
4   libruby.2.5.dylib                   0x000000010819a2eb method_super_method + 43
5   libruby.2.5.dylib                   0x00000001082681fb vm_call_cfunc + 283
6   libruby.2.5.dylib                   0x0000000108251954 vm_exec_core + 12196
7   libruby.2.5.dylib                   0x0000000108262ace vm_exec + 142
8   libruby.2.5.dylib                   0x0000000108103501 ruby_exec_internal + 177
9   libruby.2.5.dylib                   0x00000001081033f8 ruby_run_node + 56
10  ruby                                0x0000000108086f2f main + 79

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

* Loaded script: -e

* Loaded features:

    0 enumerator.so
    1 thread.rb
    2 rational.so
    3 complex.so
    4 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/x86_64-darwin17/enc/encdb.bundle
    5 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/x86_64-darwin17/enc/trans/transdb.bundle
    6 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/x86_64-darwin17/rbconfig.rb
    7 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/compatibility.rb
    8 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/defaults.rb
    9 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/deprecate.rb
   10 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/errors.rb
   11 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/version.rb
   12 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/requirement.rb
   13 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/platform.rb
   14 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/basic_specification.rb
   15 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/stub_specification.rb
   16 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/util/list.rb
   17 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/x86_64-darwin17/stringio.bundle
   18 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/specification.rb
   19 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/exceptions.rb
   20 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/dependency.rb
   21 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/core_ext/kernel_gem.rb
   22 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/monitor.rb
   23 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb
   24 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems.rb
   25 /Users/rusterholz/.rvm/rubies/ruby-2.5.0/lib/ruby/2.5.0/rubygems/path_support.rb

~~~

**Expected Results:** Given that `String.new.method(:length).super_method` correctly returns nil, I would expect `String.instance_method(:length).bind(String.new).super_method` to also return nil.

---Files--------------------------------
ruby_2018-01-29-102259_arusterholz-mbp15-9.crash (35.9 KB)


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