Good morning, After upgrade to ruby 4.0, all our Rails applications are continuously crashing on different nodes at different locations. All the applications were running flawlessly for about a year with 4.0.0.p1 and 4.0.0.p2. Reverting to 4.0.0.p2 solves the issue. The behaviour is the same with 4.0.0 and 4.0.1, where 4.0.1 has the additional issue that the value of ulimit "unlimited" has been reduced below "EFBIG", so no coredumps can be written ("too big"). Bug reporting is not possible: After registering an account on https://bugs.ruby-lang.org/, one is requested to follow the instructions in an e-mail, but such e-mail is never sent; not even after repeatedly requesting it. Versions tried: 4.0.0 (2025-12-25 revision 553f1675f3) +PRISM [amd64-freebsd14] 4.0.1 (2026-01-13 revision e04267a14b) +PRISM [amd64-freebsd14] FreeBSD-PR: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=294359 Stuff reported in the logfile (example): Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/activesupport-8.0.1/lib/active_support/core_ext/date/calculations.rb:156: [BUG] Segmentation fault at 0x0000000000000000 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: ruby 4.0.1 (2026-01-13 revision e04267a14b) +PRISM [amd64-freebsd14] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: -- Control frame information ----------------------------------------------- Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0017 p:---- s:0112 e:000111 l:y b:---- CFUNC :<=> Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0016 p:0021 s:0107 e:000106 l:y b:0001 METHOD /ext/gems/4.0/gems/activesupport-8.0.1/lib/active_support/core_ext/date/calculations.rb:156 [FINISH] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0015 p:---- s:0102 e:000101 l:y b:---- CFUNC :< Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0014 p:0150 s:0097 e:000096 l:y b:0001 METHOD /ext/rapp/fin_prod/releases/20260408164852/app/jobs/quote_fetch_job.rb:28 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0013 p:0053 s:0084 e:000083 l:y b:0001 METHOD /ext/gems/4.0/gems/que-2.4.1/lib/que/job_methods.rb:51 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0012 p:0003 s:0073 e:000072 l:y b:0001 METHOD <internal:kernel>:91 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0011 p:0007 s:0069 e:000068 l:n b:---- BLOCK /ext/gems/4.0/gems/que-2.4.1/lib/que/worker.rb:103 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0010 p:0002 s:0066 e:000065 l:n b:---- BLOCK (eval at /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:14):11 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0009 p:0027 s:0063 e:000062 l:y b:0001 METHOD /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:41 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0008 p:0011 s:0053 e:000052 l:n b:---- BLOCK /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:37 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0007 p:0002 s:0050 e:000049 l:y b:0001 METHOD /ext/gems/4.0/gems/que-2.4.1/lib/que/active_record/connection.rb:33 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0006 p:0021 s:0045 e:000044 l:y b:0001 METHOD /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:36 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0005 p:0024 s:0035 e:000034 l:y b:0001 METHOD (eval at /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:14):11 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0004 p:0050 s:0029 e:000028 l:y b:0001 METHOD /ext/gems/4.0/gems/que-2.4.1/lib/que/worker.rb:103 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0003 p:0068 s:0012 e:000011 l:y b:0001 METHOD /ext/gems/4.0/gems/que-2.4.1/lib/que/worker.rb:76 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0002 p:0026 s:0006 e:000005 l:n b:---- BLOCK /ext/gems/4.0/gems/que-2.4.1/lib/que/worker.rb:46 [FINISH] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: c:0001 p:---- s:0003 e:000002 l:y b:---- DUMMY [FINISH] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: -- Ruby level backtrace information ---------------------------------------- Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/worker.rb:46:in 'block in initialize' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/worker.rb:76:in 'work_loop' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/worker.rb:103:in 'work_job' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: (eval at /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:14):11:in 'run_job_middleware' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:36:in 'invoke_middleware' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/active_record/connection.rb:33:in 'call' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:37:in 'block in invoke_middleware' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:41:in 'invoke_middleware' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: (eval at /ext/gems/4.0/gems/que-2.4.1/lib/que/utils/middleware.rb:14):11:in 'block in run_job_middleware' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/worker.rb:103:in 'block in work_job' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: <internal:kernel>:91:in 'tap' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/que-2.4.1/lib/que/job_methods.rb:51:in '_run' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/rapp/fin_prod/releases/20260408164852/app/jobs/quote_fetch_job.rb:28:in 'run' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/rapp/fin_prod/releases/20260408164852/app/jobs/quote_fetch_job.rb:28:in '<' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/activesupport-8.0.1/lib/active_support/core_ext/date/calculations.rb:156:in 'compare_with_coercion' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/activesupport-8.0.1/lib/active_support/core_ext/date/calculations.rb:156:in '<=>' Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: -- Threading information --------------------------------------------------- Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Total ractor count: 1 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Ruby thread count for this ractor: 6 Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: -- C level backtrace information ------------------------------------------- Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_profile_frame_full_label+0x233e) [0x822ec5e2e] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_bug_reporter_add) [0x822cc5b00] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(ruby_sig_finalize) [0x822e09934] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /lib/libthr.so.3(pthread_sigmask+0x556) [0x8294dba16] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /lib/libthr.so.3(pthread_signals_unblock_np) [0x8294daf0a] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: [0x821b682d3] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_gc_adjust_memory_usage) [0x822cf7e5e] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_gc_writebarrier+0xdd) [0x822ce66fd] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/date-3.5.1/lib/date_core.so(Init_date_core+0x145) [0x830904b65] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /ext/gems/4.0/gems/date-3.5.1/lib/date_core.so(Init_date_core+0xa5) [0x8308f5655] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(ruby_free_at_exit_p) [0x822eb5106] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_error_arity) [0x822e97827] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_error_arity) [0x822e90b08] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_check_funcall) [0x822ea0571] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_scan_args_kw) [0x822c33448] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(ruby_free_at_exit_p) [0x822eb5106] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_error_arity) [0x822e97827] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_error_arity) [0x822e90b9b] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_proc_ractor_make_shareable) [0x822ea6e94] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_proc_ractor_make_shareable) [0x822ea62fa] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_internal_thread_specific_set) [0x822e607ec] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_internal_thread_specific_set) [0x822e5ff39] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /usr/local/lib/libruby40.so.40(rb_internal_thread_specific_set) [0x822e5fa01] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: /lib/libthr.so.3(pthread_create) [0x8294d1d68] Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: -- Other runtime information ----------------------------------------------- Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: * Loaded script: /ext/gems/4.0/bin/que Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: * Ruby Box: disabled Apr 9 00:30:24 <daemon.notice> rail rails-fin_prod[73556]: * Loaded features: [etc.etc.]