December 2024 - ruby-core - ml.ruby-lang.org

[ruby-core:114645] [Ruby master Bug#19865] Segfault when calling user signal handlers during VM shutdown
by ivoanjo (Ivo Anjo) 27 Aug '26

27 Aug '26

Issue #19865 has been reported by ivoanjo (Ivo Anjo). ---------------------------------------- Bug #19865: Segfault when calling user signal handlers during VM shutdown https://bugs.ruby-lang.org/issues/19865 * Author: ivoanjo (Ivo Anjo) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Howdy 👋! I work for Datadog [on the `ddtrace` gem](https://github.com/DataDog/dd-trace-rb) . I've found this issue while investigating a [customer crash report](https://github.com/DataDog/dd-trace-rb/issues/2980). ### Background The original issue was found in a production app. A number of things need to be in play to cause it. The [`ruby-odbc`](https://rubygems.org/gems/ruby-odbc) gem provides a way of accessing databases through the ODBC API. It wraps a database connection as a Data object, with a free function that, prior to freeing the native resources, disconnects from the database if the connection was still active. Because disconnecting from the database is a blocking operation, the gem (reasonably, in my opinion), releases the global VM lock before disconnecting. The trigger for the crash is: 1. The app in question used puma, and puma installs a `Signal.trap('TERM')` 2. The database object was still connected when the app started to shut down 3. A VM shutdown starts... 4. Half-way through shutdown, the VM received a SIGTERM signal, and queued it for processing 5. The VM calls the free function on all objects 6. The ruby-odbc gem sees there's an active database connection, and tries to release the GVL to call the blocking disconnect 7. Before releasing the GVL, the VM checks for pending interruptions 8. The VM tries to run the Ruby-level signal handler method half-way through VM shutdown, when you can no longer run Ruby code 9. Segfault ### How to reproduce (Ruby version & script) I was able to reproduce on a minimal example on Ruby 3.2.2 (`ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]`) and recent master (`ruby 3.3.0dev (2023-08-17T07:30:01Z master d26b015e83) [x86_64-linux]`). I've put the test-case up on github as well <https://github.com/DataDog/signal-bug-testcase>, but here's the important bits: `signal-bug-testcase.rb`: ```ruby require 'signal_bug_testcase' Signal.trap("TERM") { puts "Hello, world" } FOO = SignalBugTestcase.new ``` `signal_bug_testcase.c`: ```ruby #include <ruby.h> #include <ruby/thread.h> #include <signal.h> #include <unistd.h> typedef struct { int dummy; } BugTestcase; void *test_nogvl(void *unused) { fprintf(stderr, "GVL released!\n"); return NULL; } static void bug_testcase_free(void* ptr) { fprintf(stderr, "Free getting called! Sending signal...\n"); kill(getpid(), SIGTERM); fprintf(stderr, "SIGTERM signal queued, trying to release GVL...\n"); rb_thread_call_without_gvl(test_nogvl, NULL, NULL, NULL); fprintf(stderr, "After releasing GVL!\n"); free(ptr); } const rb_data_type_t bug_testcase_data_type = { .wrap_struct_name = "SignalBugTestcase", .function = { NULL, bug_testcase_free, NULL }, .flags = RUBY_TYPED_FREE_IMMEDIATELY }; VALUE bug_testcase_alloc(VALUE klass) { BugTestcase* obj = calloc(1, sizeof(BugTestcase)); return TypedData_Make_Struct(klass, BugTestcase, &bug_testcase_data_type, obj); } void Init_signal_bug_testcase(void) { VALUE cBugTestcase = rb_define_class("SignalBugTestcase", rb_cObject); rb_define_alloc_func(cBugTestcase, bug_testcase_alloc); } ``` ### Expectation and result No segfault happens. Interestingly, on Ruby 2.7, the VM exits half-way through but doesn't always segfault, but running it a few times always triggers the issue. On 3.2+ it crashes every time for me. I suspect the right thing here is to no longer accept/try to run any Ruby-level signal handlers after VM shutdown starts. Here's what I see with this test-case: ``` $ bundle exec ruby lib/signal-bug-testcase.rb Free getting called! Sending signal... SIGTERM signal queued, trying to release GVL... lib/signal-bug-testcase.rb:3: [BUG] Segmentation fault at 0x0000000000000007 ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux] -- Control frame information ----------------------------------------------- c:0003 p:---- s:0011 e:000010 CFUNC :puts c:0002 p:0005 s:0006 e:000005 BLOCK lib/signal-bug-testcase.rb:3 [FINISH] c:0001 p:0000 s:0003 E:0001a0 DUMMY [FINISH] -- Ruby level backtrace information ---------------------------------------- lib/signal-bug-testcase.rb:3:in `block in <main>' lib/signal-bug-testcase.rb:3:in `puts' -- Machine register context ------------------------------------------------ RIP: 0x000070aa64cedbe7 RBP: 0x000070aa648e8fd0 RSP: 0x00007ffc5c057608 RAX: 0x0000000000004171 RBX: 0x00007ffc5c057630 RCX: 0x0000000000000001 RDX: 0x00007ffc5c057630 RDI: 0x0000000000000007 RSI: 0x0000000000004171 R8: 0x000000000000021b R9: 0x0000000000000000 R10: 0x000070aa63eff048 R11: 0x0000000000000000 R12: 0x000070aa648e8fd0 R13: 0x0000000000004171 R14: 0x0000000000000007 R15: 0x000070aa648e8ff0 EFL: 0x0000000000010202 -- C level backtrace information ------------------------------------------- ruby-3.2.2/lib/libruby.so.3.2(rb_print_backtrace+0xd) [0x70aa64d5bb5f] ruby-3.2.2/vm_dump.c:785 ruby-3.2.2/lib/libruby.so.3.2(rb_vm_bugreport) ruby-3.2.2/vm_dump.c:1080 ruby-3.2.2/lib/libruby.so.3.2(rb_bug_for_fatal_signal+0xf4) [0x70aa64b52164] ruby-3.2.2/error.c:813 ruby-3.2.2/lib/libruby.so.3.2(sigsegv+0x4d) [0x70aa64cab0fd] ruby-3.2.2/signal.c:964 /lib/x86_64-linux-gnu/libc.so.6(0x70aa64642520) [0x70aa64642520] ruby-3.2.2/lib/libruby.so.3.2(hash_table_index+0x0) [0x70aa64cedbe7] ruby-3.2.2/symbol.h:72 ruby-3.2.2/lib/libruby.so.3.2(rb_id_table_lookup) ruby-3.2.2/id_table.c:230 ruby-3.2.2/lib/libruby.so.3.2(cached_callable_method_entry+0x24) [0x70aa64d356bb] ruby-3.2.2/vm_method.c:1295 ruby-3.2.2/lib/libruby.so.3.2(callable_method_entry_or_negative) ruby-3.2.2/vm_method.c:1365 ruby-3.2.2/lib/libruby.so.3.2(callable_method_entry) ruby-3.2.2/vm_method.c:1402 ruby-3.2.2/lib/libruby.so.3.2(rb_callable_method_entry) ruby-3.2.2/vm_method.c:1409 ruby-3.2.2/lib/libruby.so.3.2(gccct_method_search_slowpath+0x38) [0x70aa64d36258] ruby-3.2.2/vm_eval.c:434 ruby-3.2.2/lib/libruby.so.3.2(rb_call0+0x267) [0x70aa64d4e877] ruby-3.2.2/vm_eval.c:483 ruby-3.2.2/lib/libruby.so.3.2(rb_call+0x32) [0x70aa64d4f406] ruby-3.2.2/vm_eval.c:877 ruby-3.2.2/lib/libruby.so.3.2(rb_funcallv_kw) ruby-3.2.2/vm_eval.c:1074 ruby-3.2.2/lib/libruby.so.3.2(vm_call_cfunc_with_frame+0x127) [0x70aa64d30277] ruby-3.2.2/vm_insnhelper.c:3268 ruby-3.2.2/lib/libruby.so.3.2(vm_sendish+0x97) [0x70aa64d407a4] ruby-3.2.2/vm_insnhelper.c:5080 ruby-3.2.2/lib/libruby.so.3.2(vm_exec_core) ruby-3.2.2/insns.def:820 ruby-3.2.2/lib/libruby.so.3.2(rb_vm_exec+0xd3) [0x70aa64d460d3] ruby-3.2.2/vm.c:2374 ruby-3.2.2/lib/libruby.so.3.2(rb_vm_invoke_proc+0x5f) [0x70aa64d4bfcf] ruby-3.2.2/vm.c:1603 ruby-3.2.2/lib/libruby.so.3.2(vm_call0_body+0x5df) [0x70aa64d4c5cf] ruby-3.2.2/vm_eval.c:274 ruby-3.2.2/lib/libruby.so.3.2(vm_call0_cc+0x77) [0x70aa64d4e7e7] ruby-3.2.2/vm_eval.c:87 ruby-3.2.2/lib/libruby.so.3.2(rb_call0) ruby-3.2.2/vm_eval.c:551 ruby-3.2.2/lib/libruby.so.3.2(rb_call+0x32) [0x70aa64d4f406] ruby-3.2.2/vm_eval.c:877 ruby-3.2.2/lib/libruby.so.3.2(rb_funcallv_kw) ruby-3.2.2/vm_eval.c:1074 ruby-3.2.2/lib/libruby.so.3.2(rb_eval_cmd_kw+0x142) [0x70aa64d4f562] ruby-3.2.2/vm_eval.c:1923 ruby-3.2.2/lib/libruby.so.3.2(signal_exec+0xf6) [0x70aa64caae16] ruby-3.2.2/signal.c:1064 ruby-3.2.2/lib/libruby.so.3.2(rb_threadptr_execute_interrupts+0x36b) [0x70aa64cf7078] ruby-3.2.2/thread.c:2334 ruby-3.2.2/lib/libruby.so.3.2(rb_threadptr_execute_interrupts) ruby-3.2.2/thread.c:2291 ruby-3.2.2/lib/libruby.so.3.2(rb_vm_check_ints+0xb) [0x70aa64cf7ac5] ruby-3.2.2/vm_core.h:1994 ruby-3.2.2/lib/libruby.so.3.2(rb_vm_check_ints) ruby-3.2.2/vm_core.h:1985 ruby-3.2.2/lib/libruby.so.3.2(unblock_function_set) ruby-3.2.2/thread.c:320 ruby-3.2.2/lib/libruby.so.3.2(blocking_region_begin) ruby-3.2.2/thread.c:1485 ruby-3.2.2/lib/libruby.so.3.2(rb_nogvl+0xbf) [0x70aa64cf90cf] ruby-3.2.2/thread.c:1548 signal-bug-testcase-2/lib/signal_bug_testcase.so(fprintf+0x0) [0x70aa6518f299] ../../../../ext/signal_bug_testcase/signal_bug_testcase.c:17 signal-bug-testcase-2/lib/signal_bug_testcase.so(bug_testcase_free) ../../../../ext/signal_bug_testcase/signal_bug_testcase.c:18 ruby-3.2.2/lib/libruby.so.3.2(run_final+0xf) [0x70aa64b73172] ruby-3.2.2/gc.c:4388 ruby-3.2.2/lib/libruby.so.3.2(finalize_list) ruby-3.2.2/gc.c:4407 ruby-3.2.2/lib/libruby.so.3.2(finalize_deferred_heap_pages) ruby-3.2.2/gc.c:4436 ruby-3.2.2/lib/libruby.so.3.2(rb_objspace_call_finalizer+0x350) [0x70aa64b80d70] ruby-3.2.2/gc.c:4573 ruby-3.2.2/lib/libruby.so.3.2(rb_ec_finalize+0x2a) [0x70aa64b5d6d1] ruby-3.2.2/eval.c:168 ruby-3.2.2/lib/libruby.so.3.2(rb_ec_cleanup) ruby-3.2.2/eval.c:262 ruby-3.2.2/lib/libruby.so.3.2(ruby_run_node+0x9d) [0x70aa64b5d91d] ruby-3.2.2/eval.c:330 ruby-3.2.2/bin/ruby(rb_main+0x21) [0x5d5d1295f187] ./main.c:38 ruby-3.2.2/bin/ruby(main) ./main.c:57 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_call_main+0x80) [0x70aa64629d90] ../sysdeps/nptl/libc_start_call_main.h:58 /lib/x86_64-linux-gnu/libc.so.6(call_init+0x0) [0x70aa64629e40] ../csu/libc-start.c:392 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main_impl) ../csu/libc-start.c:379 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main) (null):0 [0x5d5d1295f1d5] ``` ---Files-------------------------------- signal-bug-testcase-main.zip (7.73 KB) -- https://bugs.ruby-lang.org/

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[ruby-core:116615] [Ruby master Bug#20243] M:N threading VM_ASSERT failure in rb_current_execution_context with clang 17 (on Linux)
by kjtsanaktsidis (KJ Tsanaktsidis) 24 Aug '26

24 Aug '26

Issue #20243 has been reported by kjtsanaktsidis (KJ Tsanaktsidis). ---------------------------------------- Bug #20243: M:N threading VM_ASSERT failure in rb_current_execution_context with clang 17 (on Linux) https://bugs.ruby-lang.org/issues/20243 * Author: kjtsanaktsidis (KJ Tsanaktsidis) * Status: Open * Priority: Normal * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- When building with Clang 17 and `-DVM_CHECK_MODE=1` (with the following configure) ``` optflags="-ggdb3 -fno-omit-frame-pointer -fno-optimize-sibling-calls -O3" cflags="-DVM_CHECK_MODE=1" CC=clang ../configure --prefix=/home/kj/ruby/installed --enable-yjit=dev --disable-install-doc ``` And then running the following script with the built `./miniruby` (which is actually from `bootstraptest/test_ractor.rb`): ```ruby counts = [] counts << Ractor.count ractors = (1..3).map { Ractor.new { Ractor.receive } } counts << Ractor.count ractors[0].send('End 0').take sleep 0.1 until ractors[0].inspect =~ /terminated/ counts << Ractor.count ractors[1].send('End 1').take sleep 0.1 until ractors[1].inspect =~ /terminated/ counts << Ractor.count ractors[2].send('End 2').take sleep 0.1 until ractors[2].inspect =~ /terminated/ counts << Ractor.count counts.inspect ``` I get the following crash: ``` Assertion Failed: ../vm_core.h:1957:rb_current_execution_context:ec == rb_current_ec_noinline() ruby 3.4.0dev (2024-02-07T07:52:06Z ktsanaktsidis/igno.. 5cc6d944c2) [x86_64-linux] -- Control frame information ----------------------------------------------- c:0003 p:0003 s:0010 e:000009 METHOD <internal:ractor>:431 c:0002 p:0004 s:0006 e:000005 BLOCK ractor_crash.rb:3 [FINISH] c:0001 p:---- s:0003 e:000002 DUMMY [FINISH] -- Ruby level backtrace information ---------------------------------------- ractor_crash.rb:3:in `block (2 levels) in <main>' <internal:ractor>:431:in `receive' -- Threading information --------------------------------------------------- Total ractor count: 2 Ruby thread count for this ractor: 1 -- C level backtrace information ------------------------------------------- /home/kj/ruby/build/miniruby(rb_print_backtrace+0x14) [0x55faa97a4ebd] ../vm_dump.c:820 /home/kj/ruby/build/miniruby(rb_vm_bugreport) ../vm_dump.c:1151 /home/kj/ruby/build/miniruby(rb_assert_failure+0x81) [0x55faa94d2719] ../error.c:1131 ./miniruby(thread_sched_wait_running_turn+0x2e9) [0x55faa9726f59] /home/kj/ruby/build/miniruby(rb_ractor_sched_sleep+0x10b) [0x55faa972687b] ../thread_pthread.c:1348 /home/kj/ruby/build/miniruby(ractor_check_ints+0x0) [0x55faa968b328] ../ractor.c:683 /home/kj/ruby/build/miniruby(ractor_sleep_with_cleanup) ../ractor.c:684 /home/kj/ruby/build/miniruby(ractor_sleep+0x15) [0x55faa968adf4] ../ractor.c:701 /home/kj/ruby/build/miniruby(ractor_wait_receive) ../ractor.c:748 /home/kj/ruby/build/miniruby(ractor_receive+0x1f) [0x55faa968768e] ../ractor.c:762 /home/kj/ruby/build/miniruby(builtin_inline_class_431) ../ractor.rb:432 /home/kj/ruby/build/miniruby(builtin_invoker0+0x6) [0x55faa978fc66] ../vm_insnhelper.c:6746 /home/kj/ruby/build/miniruby(invoke_bf+0x39) [0x55faa979816e] ../vm_insnhelper.c:6886 /home/kj/ruby/build/miniruby(vm_invoke_builtin_delegate) ../vm_insnhelper.c:6909 /home/kj/ruby/build/miniruby(rb_vm_check_ints+0x0) [0x55faa9771fac] ../insns.def:1533 /home/kj/ruby/build/miniruby(vm_pop_frame) ../vm_insnhelper.c:419 /home/kj/ruby/build/miniruby(vm_exec_core) ../insns.def:1537 /home/kj/ruby/build/miniruby(vm_exec_loop+0x0) [0x55faa9767f02] ../vm.c:2489 /home/kj/ruby/build/miniruby(rb_vm_exec) ../vm.c:2492 /home/kj/ruby/build/miniruby(invoke_block+0x6f) [0x55faa9781a58] ../vm.c:1512 /home/kj/ruby/build/miniruby(invoke_iseq_block_from_c) ../vm.c:1582 /home/kj/ruby/build/miniruby(invoke_block_from_c_proc) ../vm.c:1680 /home/kj/ruby/build/miniruby(vm_invoke_proc) ../vm.c:1710 /home/kj/ruby/build/miniruby(rb_vm_invoke_proc_with_self+0x5a) [0x55faa9781eaa] ../vm.c:1745 /home/kj/ruby/build/miniruby(thread_do_start_proc+0x199) [0x55faa9739e19] ../thread.c:574 /home/kj/ruby/build/miniruby(thread_do_start+0x6c) [0x55faa973933f] ../thread.c:618 /home/kj/ruby/build/miniruby(thread_start_func_2) ../thread.c:668 /home/kj/ruby/build/miniruby(rb_native_mutex_lock+0x0) [0x55faa973a141] ../thread_pthread.c:2234 /home/kj/ruby/build/miniruby(thread_sched_lock_) ../thread_pthread.c:387 /home/kj/ruby/build/miniruby(call_thread_start_func_2) ../thread_pthread_mn.c:436 /home/kj/ruby/build/miniruby(co_start) ../thread_pthread_mn.c:434 ``` The failing assertion is this one in vm_core.h: https://github.com/ruby/ruby/blob/42c36269403baac67b0d5dc1d6d6e31168cf6a1f/…. It actually has a very helpful comment. ``` /* On the shared objects, `__tls_get_addr()` is used to access the TLS * and the address of the `ruby_current_ec` can be stored on a function * frame. However, this address can be mis-used after native thread * migration of a coroutine. * 1) Get `ptr =&ruby_current_ec` op NT1 and store it on the frame. * 2) Context switch and resume it on the NT2. * 3) `ptr` is used on NT2 but it accesses to the TLS on NT1. * This assertion checks such misusage. * * To avoid accidents, `GET_EC()` should be called once on the frame. * Note that inlining can produce the problem. */ VM_ASSERT(ec == rb_current_ec_noinline()); ``` What seems to be happening is exactly that. This is a disassembly of the relevant bits of `thread_sched_wait_running_turn`: ``` ........ # This is the only bits of the entire function which access the TLS base register %fs. # It seems to have spilled the value of ruby_current_ec into %r13. 0x000055603d2e1cf8 <+136>: mov $0xffffffffffffff90,%rax 0x000055603d2e1cff <+143>: mov %fs:0x0,%r12 0x000055603d2e1d08 <+152>: add %rax,%r12 0x000055603d2e1d0b <+155>: mov %fs:(%rax),%r13 ........ # There's a call to coroutine_transfer, so after this point we're returned to on a # different thread 0x000055603d2e1e90 <+544>: call 0x55603d7fce84 <coroutine_transfer> # But nothing ever loads the address of ruby_current_ec from %fs again (i didn't trace # exactly the data flow from %r13 at 0x000055603d2e1d0b to here, but i assume it spilled # somewhere and now got loaded back into %r15 here). In any case, that means %r15 here # contains the value of ruby_current_ec from the _old_ thread, not the current one. 0x000055603d2e1e95 <+549>: mov %rbx,0x28(%r14) 0x000055603d2e1e99 <+553>: mov (%r12),%r15 0x000055603d2e1e9d <+557>: call 0x55603d33a010 <rb_current_ec_noinline> 0x000055603d2e1ea2 <+562>: cmp %rax,%r15 => 0x000055603d2e1ea5 <+565>: jne 0x55603d2e1f3a <thread_sched_wait_running_turn+714> ........ # assertion failure code path. 0x000055603d2e1f3a <+714>: lea 0x542c0c(%rip),%rdi # 0x55603d824b4d 0x000055603d2e1f41 <+721>: lea 0x542c12(%rip),%rdx # 0x55603d824b5a 0x000055603d2e1f48 <+728>: lea 0x542c28(%rip),%rcx # 0x55603d824b77 0x000055603d2e1f4f <+735>: mov $0x7a5,%esi 0x000055603d2e1f54 <+740>: call 0x55603d08d698 <rb_assert_failure> ``` if we look at the register values from `0x000055603d2e1ea2`: ``` (rr) print/x $rax $2 = 0x55603e159ad0 (rr) print/x $r15 $3 = 0x0 ``` So the value from `%rax` which came from `ruby_current_ec_noinline` is correctly the value of `ruby_current_ec` for this thread, and `%r15` contains a stale value from a previous thread. - Now, what can we _do_ about this, is a different question :/ There's a really good stackoverflow answer about it here: https://stackoverflow.com/questions/75592038/how-to-disable-clang-expressio…, but to summarise * longstanding GCC and Clang bugs for this exist and have been marked as WONTFIX (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26461, https://github.com/llvm/llvm-project/issues/19551) * It's even worse than this EC problem - things like `errno` also might be incorrectly persisted across coroutine switches (so e.g. an inlined C library function could in theory set `errno` in another thread, for example) * C++ actually has coroutines now, so this _must_ work for those. Clang at least has fixed some TLS problems in their C++ coroutine implementation (https://github.com/llvm/llvm-project/issues/47179) Other than reimplementing all of our coroutine stuff on top of C++ coroutines, I'm not sure what else we can do. AFAICT there's no way to tell the compiler that we clobbered the `%fs` register because that's just not a thing in its model (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66631, but i assume clang is similar). Thoughts? For now I think my workaround is to disable M:N at build time when building with ASAN (or turn optimizations down). At least this isn't a problem with `Fiber` because we never move them across threads (probably for this reason in part). -- https://bugs.ruby-lang.org/

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[ruby-core:115143] [Ruby master Bug#19970] Eval leaks callcache and callinfo objects on arm32 (linux)
by larsin (Lars Ingjer) 24 Aug '26

24 Aug '26

Issue #19970 has been reported by larsin (Lars Ingjer). ---------------------------------------- Bug #19970: Eval leaks callcache and callinfo objects on arm32 (linux) https://bugs.ruby-lang.org/issues/19970 * Author: larsin (Lars Ingjer) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [armv7l-linux-eabihf] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- The following script demonstrates a memory leak on arm 32 (linux): ``` ruby def gcdiff(n) GC.start if @last_gc_stat puts "GC.stat #{n} diff old_objects: #{GC.stat(:old_objects) - @last_gc_stat}" end @last_gc_stat = GC.stat(:old_objects) end def foo end 10.times do |i| 10_000.times do eval 'foo' end gcdiff(i) puts "Number of live objects: #{GC.stat(:heap_live_slots)}" puts "Memory usage: #{`ps -o rss= -p #{$$}`}" puts end ``` Output: ``` Number of live objects: 41303 Memory usage: 11900 GC.stat 1 diff old_objects: 20037 Number of live objects: 61317 Memory usage: 13604 GC.stat 2 diff old_objects: 20001 Number of live objects: 81317 Memory usage: 14880 GC.stat 3 diff old_objects: 20000 Number of live objects: 101317 Memory usage: 16596 GC.stat 4 diff old_objects: 20000 Number of live objects: 121317 Memory usage: 17248 GC.stat 5 diff old_objects: 20000 Number of live objects: 141317 Memory usage: 18760 GC.stat 6 diff old_objects: 20000 Number of live objects: 161317 Memory usage: 19540 GC.stat 7 diff old_objects: 20000 Number of live objects: 181317 Memory usage: 21752 GC.stat 8 diff old_objects: 20000 Number of live objects: 201317 Memory usage: 21828 GC.stat 9 diff old_objects: 20000 Number of live objects: 221317 Memory usage: 24896 ``` ObjectSpace.count_imemo_objects shows that imemo_callcache and imemo_callinfo are leaking. The issue does not occur on arm64 mac or x86_64 linux with the same ruby version. The issue has also been reproduced with the latest 3.2.2 snapshot (2023-09-30). -- https://bugs.ruby-lang.org/

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[ruby-core:111740] [Ruby master Bug#19325] Windows support lacking.
by dsisnero (Dominic Sisneros) 23 Aug '26

23 Aug '26

Issue #19325 has been reported by dsisnero (Dominic Sisneros). ---------------------------------------- Bug #19325: Windows support lacking. https://bugs.ruby-lang.org/issues/19325 * Author: dsisnero (Dominic Sisneros) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Ruby's support on windows has always been second class. With some of the recent decisions, windows support is falling even more behind. Recent developments in mjit and yjit that exclude windows are two glaring issues that should be corrected. Googling 'percent of windows vs other operating systems' and it shows windows has a share of 76%. Ceding that users to python and other programming languages has to be one of the reasons python continues get more market share from ruby. With rust having first class windows support and threading support, is there a reason why yjit is not able to work on windows? Also, windows compiler support has matured enough and vcpkg support has evolved enough that it seems it should be possible to finally get a ruby version without having to use msys2. Even Crystal language has a version that runs on windows without needing msys2. -- https://bugs.ruby-lang.org/

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[ruby-core:118182] [Ruby master Bug#20526] File.open(encoding: "bom|utf-8") converts "\r\n" to "\n" on Windows
by kou (Kouhei Sutou) 23 Aug '26

23 Aug '26

Issue #20526 has been reported by kou (Kouhei Sutou). ---------------------------------------- Bug #20526: File.open(encoding: "bom|utf-8") converts "\r\n" to "\n" on Windows https://bugs.ruby-lang.org/issues/20526 * Author: kou (Kouhei Sutou) * Status: Open * Target version: 3.2 * ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x64-mingw-ucrt] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- I'm not sure whether this is an intentional behavior but it seems that `encoding: "utf-8"` doesn't change newline conversion but `encoding: "bom|utf-8"` changes newline conversion: ```ruby File.write("a.txt", "a\r\n") File.read("a.txt").bytes # => [97, 13, 10] File.open("a.txt", encoding: "utf-8") {|f| f.read.bytes} # => [97, 10, 10] File.open("a.txt", encoding: "bom|utf-8") {|f| f.read.bytes} # => [97, 10] XXX: \r\n -> \n File.open("a.txt", encoding: "bom|utf-8", universal_newline: false) {|f| f.read.bytes} # => [97, 13, 10] ``` Note that the `XXX: ` line the above codes. Is this an intentional behavior? -- https://bugs.ruby-lang.org/

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[ruby-core:115466] [Ruby master Bug#20020] Segfault running regexp match?
by andrea.salicetti＠gmail.com (Andrea Salicetti) 23 Aug '26

23 Aug '26

Issue #20020 has been reported by andrea.salicetti(a)gmail.com (Andrea Salicetti). ---------------------------------------- Bug #20020: Segfault running regexp match? https://bugs.ruby-lang.org/issues/20020 * Author: andrea.salicetti(a)gmail.com (Andrea Salicetti) * Status: Open * Priority: Normal * ruby -v: 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-darwin23] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- **Ruby version** : ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-darwin23] From `irb`, trying to call `match?` on this regular expression causes a segmentation falut: ```ruby irb(main):001:0> /^((a|c)|\s?){1,3}$/.match?('abc') => false irb(main):002:0> /^((a|c)|\s?){1,3}$/.match?('abc') (irb):2: [BUG] Segmentation fault at 0x000000061ba998e8 ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-darwin23] -- Crash Report log information -------------------------------------------- See Crash Report log file in one of the following locations: * ~/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:0037 p:---- s:0207 e:000206 CFUNC :match? c:0036 p:0006 s:0202 e:000201 EVAL (irb):2 [FINISH] c:0035 p:---- s:0199 e:000198 CFUNC :eval c:0034 p:0020 s:0191 e:000190 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb/workspace.rb:119 c:0033 p:0153 s:0183 e:000181 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb/context.rb:502 c:0032 p:0119 s:0170 e:000169 BLOCK /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb.rb:588 c:0031 p:0024 s:0164 e:000163 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb.rb:777 c:0030 p:0007 s:0158 e:000157 BLOCK /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb.rb:567 c:0029 p:0126 s:0153 e:000152 BLOCK /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb/ruby-lex.rb:267 [FINISH] c:0028 p:---- s:0149 e:000148 CFUNC :loop c:0027 p:0005 s:0145 e:000144 BLOCK /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb/ruby-lex.rb:249 [FINISH] c:0026 p:---- s:0142 e:000141 CFUNC :catch c:0025 p:0010 s:0137 e:000136 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb/ruby-lex.rb:248 c:0024 p:0050 s:0132 E:000dd8 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb.rb:566 c:0023 p:0003 s:0127 e:000126 BLOCK /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb.rb:500 [FINISH] c:0022 p:---- s:0124 e:000123 CFUNC :catch c:0021 p:0050 s:0119 E:000d50 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb.rb:499 c:0020 p:0069 s:0113 e:000112 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/3.2.0/irb.rb:421 c:0019 p:0012 s:0107 e:000106 TOP /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/gems/3.2.0/gems/irb-1.6.2/exe/irb:11 [FINISH] c:0018 p:---- s:0104 e:000103 CFUNC :load c:0017 p:0078 s:0099 e:000098 TOP /Users/andreasalicetti/.rbenv/versions/3.2.2/bin/irb:25 [FINISH] c:0016 p:---- s:0094 e:000093 CFUNC :load c:0015 p:0064 s:0089 e:000088 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/cli/exec.rb:58 c:0014 p:0050 s:0083 e:000082 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/cli/exec.rb:23 c:0013 p:0034 s:0078 e:000077 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/cli.rb:492 c:0012 p:0054 s:0073 e:000072 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/vendor/thor/lib/thor/command.rb:28 c:0011 p:0040 s:0065 e:000064 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/vendor/thor/lib/thor/invocation.rb:127 c:0010 p:0213 s:0058 e:000057 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/vendor/thor/lib/thor.rb:527 c:0009 p:0008 s:0045 e:000044 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/cli.rb:34 c:0008 p:0044 s:0040 e:000039 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/vendor/thor/lib/thor/base.rb:584 c:0007 p:0022 s:0033 e:000032 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/cli.rb:28 c:0006 p:0042 s:0028 e:000027 BLOCK /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/gems/3.2.0/gems/bundler-2.4.22/exe/bundle:37 c:0005 p:0007 s:0022 e:000021 METHOD /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/site_ruby/3.2.0/bundler/friendly_errors.rb:117 c:0004 p:0108 s:0017 E:0019b8 TOP /Users/andreasalicetti/.rbenv/versions/3.2.2/lib/ruby/gems/3.2.0/gems/bundler-2.4.22/exe/bundle:29 [FINISH] c:0003 p:---- s:0013 e:000012 CFUNC :load c:0002 p:0081 s:0008 E:000220 EVAL /Users/andreasalicetti/.rbenv/versions/3.2.2/bin/bundle:25 [FINISH] c:0001 p:0000 s:0003 E:001980 DUMMY [FINISH] ``` Sometimes this happens the very first time I try to execute the command, some other times I have to try a couple of times to see that Segmentation Fault (but usually within the first 5 attempts). ---Files-------------------------------- ruby-2023-11-23-175410.ips (20.2 KB) -- https://bugs.ruby-lang.org/

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[ruby-core:111678] [Ruby master Feature#19315] Lazy substrings in CRuby
by Eregon (Benoit Daloze) 21 Aug '26

21 Aug '26

Issue #19315 has been reported by Eregon (Benoit Daloze). ---------------------------------------- Feature #19315: Lazy substrings in CRuby https://bugs.ruby-lang.org/issues/19315 * Author: Eregon (Benoit Daloze) * Status: Open * Priority: Normal ---------------------------------------- CRuby should implement lazy substrings, i.e., "abcdef"[1..3] must not copy bytes. Currently CRuby only reuse the char* if the substring is until the end of the buffer. But it should also work wherever the substring starts and ends. Yes, it means RSTRING_PTR() might need to allocate to \0-terminate, so be it, it's worth it. There is already code for this (`SHARABLE_MIDDLE_SUBSTRING`), but it's disabled by default and `RSTRING_PTR()` needs to be changed to deal with this. It seems a good idea to introduce a variant of `RSTRING_PTR` which doesn't guarantee \0-termination, so such callers can then use the existing bytes always without copy. There are countless workarounds for this missing optimization, all not worth and all less readable: * https://bugs.ruby-lang.org/issues/19314 * https://github.com/ruby/net-protocol/pull/14 * Manual lazy substrings which track string + index + length * More but I don't remember all now, feel free to comment or link more urls/tickets. -- https://bugs.ruby-lang.org/

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[ruby-core:116370] [Ruby master Bug#20203] `TestEnumerable` test failures with GCC 14
by vo.x (Vit Ondruch) 17 Aug '26

17 Aug '26

Issue #20203 has been reported by vo.x (Vit Ondruch). ---------------------------------------- Bug #20203: `TestEnumerable` test failures with GCC 14 https://bugs.ruby-lang.org/issues/20203 * Author: vo.x (Vit Ondruch) * Status: Open * Priority: Normal * ruby -v: ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [x86_64-linux] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- There is ongoing mass rebuild in Fedora and that is first time GCC 14 is used and we observe test failures in `TestEnumerable`. Here are a few examples: ~~~ [ 3000/26419] TestEnumerable#test_transient_heap_sort_bymalloc_consolidate(): unaligned fastbin chunk detected ~~~ ~~~ [ 2455/26535] TestEnumerable#test_transient_heap_sort_bycorrupted size vs. prev_size in fastbins ~~~ ~~~ [ 9716/26532] TestEnumerable#test_any_with_unused_blockdouble free or corruption (fasttop) ~~~ The full logs are accessible [here](https://koji.fedoraproject.org/koji/taskinfo?taskID=112176941). Please drill through `Descendants` and `build.log` -- https://bugs.ruby-lang.org/

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[ruby-core:117483] [Ruby master Bug#20419] [BUG] inconsistent freelist length with cppflags='-DRGENGC_CHECK_MODE -DUSE_RUBY_DEBUG_LOG=1'
by znz (Kazuhiro NISHIYAMA) 16 Aug '26

16 Aug '26

Issue #20419 has been reported by znz (Kazuhiro NISHIYAMA). ---------------------------------------- Bug #20419: [BUG] inconsistent freelist length with cppflags='-DRGENGC_CHECK_MODE -DUSE_RUBY_DEBUG_LOG=1' https://bugs.ruby-lang.org/issues/20419 * Author: znz (Kazuhiro NISHIYAMA) * Status: Open * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- `TestGc#test_gc_stress_at_startup` failed on my environment, so I check which configure flags affect. How to reproduce: ``` ./configure cppflags='-DRGENGC_CHECK_MODE -DUSE_RUBY_DEBUG_LOG=1' make miniruby env RUBY_DEBUG=gc_stress ./miniruby -v ``` I can't reproduce with `cppflags='-DRGENGC_CHECK_MODE'` or `cppflags='-DUSE_RUBY_DEBUG_LOG=1'`. ---Files-------------------------------- output.txt (9.44 KB) -- https://bugs.ruby-lang.org/

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[ruby-core:116226] [Ruby master Bug#20189] `rb_str_resize` does not clear coderange when expanding
by tompng (tomoya ishida) 16 Aug '26

16 Aug '26

Issue #20189 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #20189: `rb_str_resize` does not clear coderange when expanding https://bugs.ruby-lang.org/issues/20189 * Author: tompng (tomoya ishida) * Status: Open * Priority: Normal * ruby -v: ruby 3.4.0dev (2024-01-09T07:07:19Z master db476cc71c) [x86_64-linux] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Expanding string in some encoding (utf16 utf32) can change coderange to either valid or broken, but rb_str_resize does not clear coderange. This will cause a bug in c-extension libraries that use rb_str_resize. ~~~ruby # Example for stringio s = StringIO.new("\0".encode('UTF-16LE')) s.truncate(1); s.truncate(2); s.string.valid_encoding? #=> true s.truncate(1); s.string.valid_encoding?; s.truncate(2); s.string.valid_encoding? #=> false (expect to be true) ~~~ -- https://bugs.ruby-lang.org/

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