Bug #22016: ruby segfaults regularly

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: ruby 4.0.2 (2026-03-17 revision d3da9fec82) +PRISM [x86_64-netbsd]
• Backport: 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN

[wiz (Thomas Klausner)]

When using ruby 4.0.2 on NetBSD-11.99.5/x86_64, built from pkgsrc, I often get core dumps.
Recently it was quite easy to get them using asciidoctor to build the documentation for vms-empire (but that is just one example).

Here is the backtrace of the latest coredump:

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Reading symbols from ruby40...

⚠️ warning: exec file is newer than core file.
[New process 29975]
[New process 316]
Core was generated by `ruby40'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007af7bc25f99a in _lwp_kill () from /usr/lib/libc.so.12
[Current thread is 1 (process 29975)]
#0  0x00007af7bc25f99a in _lwp_kill () from /usr/lib/libc.so.12
#1  0x00007af7bc926422 in rb_bug_for_fatal_signal (default_sighandler=0x0, sig=sig@entry=11, ctx=ctx@entry=0x7af7a1f6e420, fmt=fmt@entry=0x7af7bca2ec38 "Segmentation fault at %p") at error.c:1135
#2  0x00007af7bc7d2406 in sigsegv (sig=11, info=0x7af7a1f6e3a0, ctx=0x7af7a1f6e420) at signal.c:948
#3  <signal handler called>
#4  each_location (x=0x7f7fff7c3000, n=338431, cb=cb@entry=0x7af7bc6b4ef5 <gc_mark_machine_stack_location_maybe>, data=0x0) at gc.c:2682
#5  0x00007af7bc6a955b in each_location_ptr (data=0x0, start=<optimized out>, end=<optimized out>, cb=0x7af7bc6b4ef5 <gc_mark_machine_stack_location_maybe>) at gc.c:2691
#6  each_location_ptr (start=<optimized out>, end=<optimized out>, cb=0x7af7bc6b4ef5 <gc_mark_machine_stack_location_maybe>, data=0x0) at gc.c:2688
#7  rb_gc_mark_machine_context (ec=0x7af7bc023650) at gc.c:2978
#8  mark_current_machine_context (ec=0x7af7bc023650) at gc.c:2958
#9  rb_gc_mark_roots (objspace=<optimized out>, categoryp=0x0) at gc.c:3056
#10 mark_roots (objspace=<optimized out>, categoryp=0x0) at gc/default/default.c:4629
#11 0x00007af7bc6bd047 in gc_marks_start (objspace=0x7af7bc018000, full_mark=<optimized out>) at gc/default/default.c:5815
#12 gc_marks (objspace=0x7af7bc018000, full_mark=<optimized out>) at gc/default/default.c:5831
#13 gc_start (objspace=objspace@entry=0x7af7bc018000, reason=<optimized out>, reason@entry=256) at gc/default/default.c:6516
#14 0x00007af7bc6bdd17 in heap_prepare (objspace=0x7af7bc018000, heap=0x7af7bc018028) at gc/default/default.c:2086
#15 heap_next_free_page (objspace=0x7af7bc018000, heap=0x7af7bc018028) at gc/default/default.c:2301
#16 newobj_cache_miss (objspace=0x7af7bc018000, cache=0x7af7bc000000, heap_idx=0, vm_locked=vm_locked@entry=false) at gc/default/default.c:2408
#17 0x00007af7bc6be719 in newobj_alloc (objspace=<optimized out>, cache=<optimized out>, heap_idx=<optimized out>, vm_locked=false) at gc/default/default.c:2432
#18 rb_gc_impl_new_obj (objspace_ptr=<optimized out>, cache_ptr=<optimized out>, klass=135203969407320, flags=8218, wb_protected=<optimized out>, alloc_size=<optimized out>) at gc/default/default.c:2511
#19 newobj_of (cr=<optimized out>, klass=135203969407320, flags=8218, shape_id=0, wb_protected=<optimized out>, size=<optimized out>) at gc.c:996
#20 0x00007af7bc84fcca in svar_new (obj=<optimized out>) at vm_insnhelper.c:642
#21 lep_svar_set (ec=0x7af7bc023650, lep=0x7af7bbefe6a0, key=key@entry=1, val=val@entry=4) at vm_insnhelper.c:656
#22 0x00007af7bc860c19 in vm_cfp_svar_set (ec=<optimized out>, cfp=<optimized out>, key=1, val=4) at vm.c:2014
#23 0x00007af7bc7983f9 in rb_reg_search_set_match (re=re@entry=135203970164480, str=str@entry=135203969420880, pos=pos@entry=0, reverse=reverse@entry=0, set_backref_str=set_backref_str@entry=-1, 
    set_match=set_match@entry=0x7f7fff7bea60) at re.c:1795
#24 0x00007af7bc798707 in rb_reg_search0 (re=re@entry=135203970164480, str=str@entry=135203969420880, pos=pos@entry=0, reverse=reverse@entry=0, set_backref_str=set_backref_str@entry=-1, match=match@entry=0x7f7fff7bea60)
    at re.c:1857
#25 0x00007af7bc7ef856 in rb_pat_search0 (pat=pat@entry=135203970164480, str=str@entry=135203969420880, pos=pos@entry=0, set_backref_str=set_backref_str@entry=-1, match=match@entry=0x7f7fff7bea60) at string.c:6167
#26 0x00007af7bc7febcf in str_gsub (argc=<optimized out>, argv=<optimized out>, str=135203969420880, bang=0) at string.c:6352
#27 0x00007af7bc8612a1 in vm_call_cfunc_with_frame_ (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe310, calling=<optimized out>, argc=1, argv=0x7af7bbefe6b0, stack_bottom=0x7af7bbefe6a8) at vm_insnhelper.c:3902
#28 0x00007af7bc865da4 in vm_sendish (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe310, cd=0x7af7a0a0f8b0, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_callinfo.h:450
#29 0x00007af7bc86c200 in vm_exec_core (ec=0x62, ec@entry=0x7af7bc023650) at insns.def:856
#30 0x00007af7bc871288 in vm_exec_loop (ec=<optimized out>, state=<optimized out>, tag=<optimized out>, result=<optimized out>) at vm.c:2825
#31 rb_vm_exec (ec=0x7af7bc023650) at vm.c:2801
#32 0x00007af7bc874d19 in invoke_iseq_block_from_c (ec=<optimized out>, captured=<optimized out>, self=<optimized out>, argc=<optimized out>, argv=<optimized out>, kw_splat=<optimized out>, 
    passed_block_handler=<optimized out>, cref=0x4, is_lambda=<optimized out>, me=0x0) at vm.c:1820
#33 0x00007af7bc87628e in vm_yield_with_cref (ec=<optimized out>, argc=1, argv=0x7f7fff7beec8, kw_splat=0, cref=0x0, is_lambda=0) at vm.c:1865
#34 vm_yield (ec=<optimized out>, argc=1, argv=0x7f7fff7beec8, kw_splat=0) at vm.c:1879
#35 rb_yield_0 (argc=1, argv=0x7f7fff7beec8) at vm_eval.c:1362
#36 rb_yield (val=<optimized out>) at vm_eval.c:1378
#37 0x00007af7bc6c2366 in each_value_i (key=<optimized out>, value=<optimized out>, _=<optimized out>) at hash.c:3033
#38 0x00007af7bc6c3d42 in hash_foreach_iter () at hash.c:1269
#39 0x00007af7bc7ddb73 in st_general_foreach (tab=<optimized out>, func=0x7af7bc6c3d1b <hash_foreach_iter>, replace=0x0, arg=140187723886960, check_p=1) at st.c:1564
#40 0x00007af7bc6c4c9c in hash_foreach_call (arg=140187723886960) at hash.c:1396
#41 0x00007af7bc69a725 in rb_ec_ensure (ec=0x7af7bc023650, b_proc=<optimized out>, data1=<optimized out>, e_proc=0x7af7bc6c224a <hash_foreach_ensure>, data2=135203970494680) at eval.c:1146
#42 0x00007af7bc69a8dc in rb_ensure (b_proc=<optimized out>, data1=<optimized out>, e_proc=<optimized out>, data2=<optimized out>) at eval.c:1163
#43 0x00007af7bc6c734c in rb_hash_foreach (hash=hash@entry=135203970494680, func=func@entry=0x7af7bc6c2345 <each_value_i>, farg=farg@entry=0) at hash.c:1420
#44 0x00007af7bc6c8404 in rb_hash_each_value (hash=135203970494680) at hash.c:3061
#45 0x00007af7bc8612a1 in vm_call_cfunc_with_frame_ (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe3b8, calling=<optimized out>, argc=0, argv=0x7af7bbefe638, stack_bottom=0x7af7bbefe630) at vm_insnhelper.c:3902
#46 0x00007af7bc865da4 in vm_sendish (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe3b8, cd=0x7af7a0ab1c60, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_callinfo.h:450
#47 0x00007af7bc86c200 in vm_exec_core (ec=0x62, ec@entry=0x7af7bc023650) at insns.def:856
#48 0x00007af7bc871288 in vm_exec_loop (ec=<optimized out>, state=<optimized out>, tag=<optimized out>, result=<optimized out>) at vm.c:2825
#49 rb_vm_exec (ec=0x7af7bc023650) at vm.c:2801
#50 0x00007af7bc6fd247 in require_internal (ec=ec@entry=0x7af7bc023650, fname=<optimized out>, fname@entry=135203969759680, exception=exception@entry=1, warn=<optimized out>) at load.c:1341
#51 0x00007af7bc6fd2ef in rb_require_string_internal (fname=135203969759680, resurrect=resurrect@entry=false) at load.c:1451
#52 0x00007af7bc6fdcd8 in rb_require_string (fname=<optimized out>) at load.c:1437
#53 0x00007af7bc8612a1 in vm_call_cfunc_with_frame_ (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe460, calling=<optimized out>, argc=1, argv=0x7af7bbefe5e0, stack_bottom=0x7af7bbefe5d8) at vm_insnhelper.c:3902
#54 0x00007af7bc86b8fd in vm_sendish (ec=<optimized out>, reg_cfp=<optimized out>, cd=<optimized out>, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_callinfo.h:450
#55 vm_exec_core (ec=0x62, ec@entry=0x7af7bc023650) at insns.def:904
#56 0x00007af7bc871288 in vm_exec_loop (ec=<optimized out>, state=<optimized out>, tag=<optimized out>, result=<optimized out>) at vm.c:2825
#57 rb_vm_exec (ec=0x7af7bc023650) at vm.c:2801
#58 0x00007af7bc6fd247 in require_internal (ec=ec@entry=0x7af7bc023650, fname=<optimized out>, fname@entry=135203970210040, exception=exception@entry=1, warn=<optimized out>) at load.c:1341
#59 0x00007af7bc6fd2ef in rb_require_string_internal (fname=135203970210040, resurrect=resurrect@entry=false) at load.c:1451
#60 0x00007af7bc6fdcd8 in rb_require_string (fname=<optimized out>) at load.c:1437
#61 0x00007af7bc8612a1 in vm_call_cfunc_with_frame_ (ec=0x7af7bc023650, reg_cfp=0x7af7bbffe4d0, calling=<optimized out>, argc=1, argv=0x7af7bbefe580, stack_bottom=0x7af7bbefe578) at vm_insnhelper.c:3902
#62 0x00007af7bc86b8fd in vm_sendish (ec=<optimized out>, reg_cfp=<optimized out>, cd=<optimized out>, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_callinfo.h:450
#63 vm_exec_core (ec=0x62, ec@entry=0x7af7bc023650) at insns.def:904
#64 0x00007af7bc871288 in vm_exec_loop (ec=<optimized out>, state=<optimized out>, tag=<optimized out>, result=<optimized out>) at vm.c:2825
#65 rb_vm_exec (ec=0x7af7bc023650) at vm.c:2801
#66 0x00007af7bc7c30ba in ruby_init_prelude () at ruby.c:1779
#67 ruby_opt_init (opt=opt@entry=0x7f7fff7c09d0) at ruby.c:1829
#68 0x00007af7bc7c5038 in ruby_opt_init (opt=0x7f7fff7c09d0) at ruby.c:1799
#69 prism_script (opt=0x7f7fff7c09d0, result=0x7f7fff7c0188) at ruby.c:2234
#70 process_options (argc=6, argc@entry=8, argv=0x7f7fff7c0c08, argv@entry=0x7f7fff7c0bf8, opt=0x7f7fff7c09d0) at ruby.c:2569
#71 0x00007af7bc7c54e0 in ruby_process_options (argc=argc@entry=8, argv=argv@entry=0x7f7fff7c0bf8) at ruby.c:226
#72 0x00007af7bc69b894 in ruby_options (argc=argc@entry=8, argv=argv@entry=0x7f7fff7c0bf8) at eval.c:119
#73 0x0000000000a045e3 in rb_main (argc=8, argv=0x7f7fff7c0bf8) at ./main.c:42
#74 main (argc=<optimized out>, argv=<optimized out>) at ./main.c:62
[?2004h(gdb) quit
[?2004l

[wiz (Thomas Klausner)]

And here is the output of the process itself:

asciidoctor40 -D. -a nofooter -b manpage vms-empire.adoc
/usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:311: [BUG] Segmentation fault at 0x00007f7fff7c3000
ruby 4.0.2 (2026-03-17 revision d3da9fec82) +PRISM [x86_64-netbsd]

-- Control frame information -----------------------------------------------
c:0011 p:---- s:0050 e:000049 l:y b:---- CFUNC  :gsub
c:0010 p:0011 s:0045 e:000044 l:y b:0001 METHOD /usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:311
c:0009 p:0006 s:0038 e:000037 l:n b:---- BLOCK  /usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:329 [FINISH]
c:0008 p:---- s:0034 e:000033 l:y b:---- CFUNC  :each_value
c:0007 p:2379 s:0030 e:000029 l:y b:0001 CLASS  /usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:328
c:0006 p:0007 s:0027 e:000026 l:y b:0001 TOP    /usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:11 [FINISH]
c:0005 p:---- s:0024 e:000023 l:y b:---- CFUNC  :require
c:0004 p:0005 s:0019 e:000018 l:y b:0001 TOP    /usr/pkg/lib/ruby/4.0.0/rubygems.rb:9 [FINISH]
c:0003 p:---- s:0012 e:000011 l:y b:---- CFUNC  :require
c:0002 p:0012 s:0007 e:000006 l:y b:0001 TOP    <internal:gem_prelude>:2 [FINISH]
c:0001 p:0000 s:0003 E:000040 l:y b:---- DUMMY  [FINISH]

-- Ruby level backtrace information ----------------------------------------
<internal:gem_prelude>:2:in '<internal:gem_prelude>'
<internal:gem_prelude>:2:in 'require'
/usr/pkg/lib/ruby/4.0.0/rubygems.rb:9:in '<top (required)>'
/usr/pkg/lib/ruby/4.0.0/rubygems.rb:9:in 'require'
/usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:11:in '<top (required)>'
/usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:328:in '<module:RbConfig>'
/usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:328:in 'each_value'
/usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:329:in 'block in <module:RbConfig>'
/usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:311:in 'expand'
/usr/pkg/lib/ruby/4.0.0/x86_64-netbsd/rbconfig.rb:311:in 'gsub'

-- Threading information ---------------------------------------------------
Total ractor count: 1
Ruby thread count for this ractor: 1

-- C level backtrace information -------------------------------------------
unknown address_size:117Unexpected size of .debug_line in /usr/pkg/lib/libruby40.so.40
/usr/pkg/lib/libruby40.so.40(rb_profile_frame_full_label+0x21b) [0x7af7bc8881c4]
/usr/pkg/lib/libruby40.so.40(rb_bug_reporter_add+0x11b) [0x7af7bc690f6f]
/usr/pkg/lib/libruby40.so.40(rb_shape_memsize+0x5b) [0x7af7bc7d2406]
/usr/lib/libc.so.12(__sigtramp_siginfo_2+0x0) [0x7af7bc25fa50]
/usr/pkg/lib/libruby40.so.40(rb_find_file+0x2d) [0x7af7bc6a8437]
/usr/pkg/lib/libruby40.so.40(rb_find_file+0xc1) [0x7af7bc6a955b]
/usr/pkg/lib/libruby40.so.40(rb_gc_disable+0x35b) [0x7af7bc6bd047]
/usr/pkg/lib/libruby40.so.40(rb_gc_disable+0x2cd) [0x7af7bc6bdd17]
/usr/pkg/lib/libruby40.so.40(rb_gc_disable+0x28a) [0x7af7bc6be719]
/usr/pkg/lib/libruby40.so.40(rb_f_notimplement+0x76) [0x7af7bc84fcca]
/usr/pkg/lib/libruby40.so.40(rb_reg_onig_match+0x1cd) [0x7af7bc7983f9]
/usr/pkg/lib/libruby40.so.40(rb_str_buf_append+0xe3) [0x7af7bc7febcf]
/usr/pkg/lib/libruby40.so.40(rb_sourceline+0x142) [0x7af7bc8612a1]
/usr/pkg/lib/libruby40.so.40(rb_method_boundp+0x11e) [0x7af7bc865da4]
/usr/pkg/lib/libruby40.so.40(rb_check_funcall+0xa22) [0x7af7bc86c200]
/usr/pkg/lib/libruby40.so.40(rb_check_funcall+0xa9) [0x7af7bc871288]
/usr/pkg/lib/libruby40.so.40(rb_yield+0xdb) [0x7af7bc87628e]
/usr/pkg/lib/libruby40.so.40(rb_hash_freeze+0x21) [0x7af7bc6c2366]
/usr/pkg/lib/libruby40.so.40(rb_hash_freeze+0x27) [0x7af7bc6c3d42]
/usr/pkg/lib/libruby40.so.40(rb_st_numhash+0x94) [0x7af7bc7ddb73]
/usr/pkg/lib/libruby40.so.40(rb_hash_freeze+0x116) [0x7af7bc6c4c9c]
/usr/pkg/lib/libruby40.so.40(rb_protect+0xac) [0x7af7bc69a725]
/usr/pkg/lib/libruby40.so.40(rb_hash_foreach+0x97) [0x7af7bc6c734c]
/usr/pkg/lib/libruby40.so.40(rb_hash_clear+0x39) [0x7af7bc6c8404]
/usr/pkg/lib/libruby40.so.40(rb_sourceline+0x142) [0x7af7bc8612a1]
/usr/pkg/lib/libruby40.so.40(rb_method_boundp+0x11e) [0x7af7bc865da4]
/usr/pkg/lib/libruby40.so.40(rb_check_funcall+0xa22) [0x7af7bc86c200]
/usr/pkg/lib/libruby40.so.40(rb_check_funcall+0xa9) [0x7af7bc871288]
/usr/pkg/lib/libruby40.so.40(rb_iseq_trace_set_all+0x912) [0x7af7bc6fd247]
/usr/pkg/lib/libruby40.so.40(rb_iseq_trace_set_all+0x6f) [0x7af7bc6fd2ef]
/usr/pkg/lib/libruby40.so.40(rb_require_string+0x36) [0x7af7bc6fdcd8]
/usr/pkg/lib/libruby40.so.40(rb_sourceline+0x142) [0x7af7bc8612a1]
/usr/pkg/lib/libruby40.so.40(rb_check_funcall+0x11f) [0x7af7bc86b8fd]
/usr/pkg/lib/libruby40.so.40(rb_check_funcall+0xa9) [0x7af7bc871288]
/usr/pkg/lib/libruby40.so.40(rb_iseq_trace_set_all+0x912) [0x7af7bc6fd247]
/usr/pkg/lib/libruby40.so.40(rb_iseq_trace_set_all+0x6f) [0x7af7bc6fd2ef]
/usr/pkg/lib/libruby40.so.40(rb_require_string+0x36) [0x7af7bc6fdcd8]
/usr/pkg/lib/libruby40.so.40(rb_sourceline+0x142) [0x7af7bc8612a1]
/usr/pkg/lib/libruby40.so.40(rb_check_funcall+0x11f) [0x7af7bc86b8fd]
/usr/pkg/lib/libruby40.so.40(rb_check_funcall+0xa9) [0x7af7bc871288]
/usr/pkg/lib/libruby40.so.40(ruby_set_script_name+0xc0) [0x7af7bc7c30ba]
/usr/pkg/lib/libruby40.so.40(ruby_set_argv+0x1626) [0x7af7bc7c5038]
/usr/pkg/lib/libruby40.so.40(ruby_process_options+0x151) [0x7af7bc7c54e0]
/usr/pkg/lib/libruby40.so.40(ruby_options+0xcf) [0x7af7bc69b894]
/usr/pkg/bin/ruby40(rb_main+0x19) [0xa045e3] ./main.c:42
/usr/pkg/bin/ruby40(main) ./main.c:62
/usr/pkg/bin/ruby40(__start) (null):0

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

gmake: *** [Makefile:36: vms-empire.1] Segmentation fault (core dumped)
gmake: *** Waiting for unfinished jobs....
*** Error code 2

[luke-gru (Luke Gruber)]

Can you please provide the output of lscpu and/or uname -a along with the version of gcc? What happens when you install this exact Ruby version without pkgsrc, like from git or a tarball? Thanks.

[wiz (Thomas Klausner)]

• File ruby-build.log ruby-build.log added

Ruby does not compile out of the box for me, I'll attach the build log. I've attached the build log of a plain ruby build outside of pkgsrc, same system.
I don't know why it uses clang by default, 'cc' is gcc 14.3.0.

In case you're interested in the details of what pkgsrc does to build ruby, you can check https://github.com/NetBSD/pkgsrc/tree/trunk/lang/ruby40

There is no lscpu on NetBSD, the machine I'm using has a "AMD Ryzen 9 7950X 16-Core Processor", but others have seen this problem too.

[wiz (Thomas Klausner)]

Oh, sorry, you asked for more information:
uname -a was in the original bug report, I'm using NetBSD 11.99.5 on x86_64 (= amd64).