Segfault on Thread

[m-zielinski]

Maybe I'm doing smth wrong, but the simplest script with Vernier segfaults for me if I use Thread:

require 'vernier'

Vernier.trace(out: 'profile.json') do
  Thread.new { sleep 1 }.join # works fine without it
end

vernier 0.30 Ruby 3.2.0

[BUG] Segmentation fault at 0x0000000000000020
ruby 3.2.0 (2022-12-25 revision a528908271) [x86_64-linux]

-- Control frame information -----------------------------------------------

-- Machine register context ------------------------------------------------
 RIP: 0x00007f55ec391de9 RBP: 0x0000000000000800 RSP: 0x00007f55dff305e0
 RAX: 0x0000000000000000 RBX: 0x0000000000000000 RCX: 0x00007f55e6acfe00
 RDX: 0x0000000000000000 RDI: 0x00007f55ec66df90 RSI: 0x0000000000000800
  R8: 0x0000000000000000  R9: 0x0000000000000000 R10: 0x0000000000000000
 R11: 0x0000000000000286 R12: 0x0000000000000000 R13: 0xffffffffffffffc0
 R14: 0x00007f55e6acfe00 R15: 0x0000000000000000 EFL: 0x0000000000010203

-- C level backtrace information -------------------------------------------
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(rb_print_backtrace+0x11) [0x7f55ec393bd4] vm_dump.c:785
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(rb_vm_bugreport) vm_dump.c:1080
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(rb_bug_for_fatal_signal+0xf4) [0x7f55ec18da74] error.c:813
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(sigsegv+0x4d) [0x7f55ec2e5e7d] signal.c:964
/lib/x86_64-linux-gnu/libpthread.so.0(__restore_rt+0x0) [0x7f55ebe7f420]
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(VM_ENV_FLAGS+0x0) [0x7f55ec391de9] vm_backtrace.c:1586
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(VM_FRAME_CFRAME_P) vm_core.h:1341
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(VM_FRAME_RUBYFRAME_P) vm_core.h:1350
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(rb_profile_frames) vm_backtrace.c:1587
/home/marek/.rbenv/versions/3.2.0/lib/ruby/gems/3.2.0/gems/vernier-0.3.0/lib/vernier/vernier.so(0x7f55e6d03272) [0x7f55e6d03272]
/home/marek/.rbenv/versions/3.2.0/lib/ruby/gems/3.2.0/gems/vernier-0.3.0/lib/vernier/vernier.so(_ZN19GlobalSignalHandler14signal_handlerEiP9siginfo_tPv) (null):0
/lib/x86_64-linux-gnu/libpthread.so.0(__restore_rt+0x0) [0x7f55ebe7f420]
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(thread_start_func_2+0x1f7) [0x7f55ec332be7] thread.c:676
/home/marek/.rbenv/versions/3.2.0/lib/libruby.so.3.2(thread_start_func_1+0xf0) [0x7f55ec3339d0] thread_pthread.c:1170
/lib/x86_64-linux-gnu/libpthread.so.0(start_thread+0xd9) [0x7f55ebe73609]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x43) [0x7f55ebd98133]

[casperisfine]

You are using Ruby 3.2.0, which has a "bug" in rb_profile_frame: https://github.com/tmm1/stackprof/blob/91d12e77b3d3c5014870b4ee7c19eab24ad04b5b/lib/stackprof.rb#L13-L18

It may crash when called asynchronously.

Try upgrading to 3.2.2.

[m-zielinski]

Thank you! It works with ruby 3.2.2 (also 3.2.1). Maybe it's worth mentioning in the readme or even gemspec...?