Bug 1417590

Summary: Ruby compiled with GCC 7.x+ segfaults
Product: [Fedora] Fedora Reporter: Vít Ondruch <vondruch>
Component: rubyAssignee: Vít Ondruch <vondruch>
Status: CLOSED RAWHIDE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: rawhideCC: cben, davejohansen, jakub, jwakely, law, mmorsi, mpolacek, mtasaka, s, strzibny, vanmeeuwen+fedora, vondruch
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: ruby-2.4.0-76.fc26 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2017-02-03 15:38:40 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 1412274    

Description Vít Ondruch 2017-01-30 11:21:49 UTC 
Description of problem:
Ruby test suite segfaults presumably due to GCC 7.

This is the backtrace:

```
- C level backtrace information -------------------------------------------
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_print_backtrace+0x15) [0x7faabe1c1955] vm_dump.c:679
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_vm_bugreport+0x21c) [0x7faabe1c1b8c] vm_dump.c:988
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_bug_context+0xd4) [0x7faabe09bcb4] error.c:426
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(sigsegv+0x3e) [0x7faabe1574fe] signal.c:907
/lib64/libpthread.so.0 [0x7faabde08b50]
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(str_buf_cat+0x1c) [0x7faabe16d6dc] string.c:2571
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(w_nbyte+0x1a) [0x7faabe0d95fa] marshal.c:270
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(w_class+0x8a) [0x7faabe0da87a] marshal.c:281
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(w_object+0xb24) [0x7faabe0db434] marshal.c:733
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_marshal_dump_limited+0xe8) [0x7faabe0dbc58] marshal.c:1051
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_call_cfunc+0xf3) [0x7faabe1ac013] vm_insnhelper.c:1752
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_exec_core+0x46c) [0x7faabe1aed4c] insns.def:1066
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_exec+0x88) [0x7faabe1b52d8] vm.c:1712
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_yield+0x428) [0x7faabe1b83d8] vm.c:969
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_ary_each+0x3c) [0x7faabe0430cc] array.c:1824
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_call_cfunc+0xf3) [0x7faabe1ac013] vm_insnhelper.c:1752
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_exec_core+0x5ff) [0x7faabe1aeedf] insns.def:967
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_exec+0x88) [0x7faabe1b52d8] vm.c:1712
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_yield+0x428) [0x7faabe1b83d8] vm.c:969
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_ary_each+0x3c) [0x7faabe0430cc] array.c:1824
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_call_cfunc+0xf3) [0x7faabe1ac013] vm_insnhelper.c:1752
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_call_method+0xd3) [0x7faabe1ba073] vm_insnhelper.c:2291
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_exec_core+0x5ff) [0x7faabe1aeedf] insns.def:967
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_exec+0x88) [0x7faabe1b52d8] vm.c:1712
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_yield+0x428) [0x7faabe1b83d8] vm.c:969
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(rb_ensure+0xba) [0x7faabe0a1b6a] eval.c:926
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(dir_s_chdir+0xb4) [0x7faabe08be24] dir.c:1043
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_call_cfunc+0xf3) [0x7faabe1ac013] vm_insnhelper.c:1752
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_call_method+0xd3) [0x7faabe1ba073] vm_insnhelper.c:2291
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_exec_core+0x5ff) [0x7faabe1aeedf] insns.def:967
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(vm_exec+0x88) [0x7faabe1b52d8] vm.c:1712
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(ruby_exec_internal+0xad) [0x7faabe09f16d] eval.c:244
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(ruby_exec_node+0x1d) [0x7faabe0a0dad] eval.c:308
/builddir/build/BUILD/ruby-2.4.0/libruby.so.2.4.0(ruby_run_node+0x1e) [0x7faabe0a2d6e] eval.c:300
/builddir/build/BUILD/ruby-2.4.0/ruby(main+0x4b) [0x5610f1fe08cb] main.c:36
```

Please see Koschei for the build logs:

https://apps.fedoraproject.org/koschei/package/ruby?collection=f26


Version-Release number of selected component (if applicable):
7.0.1-0.3.fc26

How reproducible:


Steps to Reproduce:
1.
2.
3.

Actual results:
Ruby segfaults.


Expected results:
Ruby keeps working.


Additional info:
Comment 1 Jakub Jelinek 2017-01-30 11:29:25 UTC 
Yes, we saw that in the test mass rebuild.  But it was quite random failure, valgrind reported tons of unitialized memory uses in miniruby (and jump conditionalized on uninitialized memory uses), and also reports approximately same huge amount of those when miniruby is built with gcc 6.  Therefore, we assume ruby it is ruby that is buggy (until proven otherwise).
Comment 2 Vít Ondruch 2017-01-30 11:39:48 UTC 
True, it is some marshaling code, so it might be more sensitive to compiler changes. I'll report this upstream and will see. Thx for the feedback.
Comment 3 Jakub Jelinek 2017-01-30 11:53:19 UTC 
Note that when all of miniruby is built with -O0, then it doesn't crash, but trying to mix -O0 and -O2 objects the results are quite randomish, it isn't a single problematic *.o file or some small set of them that matter.  So this really needs analysis from those who know the ruby source.  It is possible it is a GCC bug, but we'd need far more details on what to look for (ideally reduced runtime testcase with details what is wrong).
Comment 4 Mamoru TASAKA 2017-02-03 13:28:18 UTC 
Looks like applying
https://github.com/ruby/ruby/commit/7c1b30a602ab109d8d5388d7dfb3c5b180ba24e1
makes ruby compile on rawhide:
https://koji.fedoraproject.org/koji/taskinfo?taskID=17563070

ref:
https://bugs.ruby-lang.org/issues/13150

scratch build of 2.4.0-75.fc26 fails (again)
https://koji.fedoraproject.org/koji/taskinfo?taskID=17564297
Comment 5 Vít Ondruch 2017-02-03 15:38:40 UTC 
(In reply to Mamoru TASAKA from comment #4)
Thx for pointing this out. I applied the patch and Ruby is building again.