[ruby-core:113386] [Ruby master Feature#19627] Add a way to detect if the Ruby VM is running in C API
2 May
2023
2 May
'23
12:29 a.m.
Issue #19627 has been reported by ianks (Ian Ker-Seymer).
----------------------------------------
Feature #19627: Add a way to detect if the Ruby VM is running in C API
https://bugs.ruby-lang.org/issues/19627
* Author: ianks (Ian Ker-Seymer)
* Status: Open
* Priority: Normal
----------------------------------------
Currently, there is no supported way to check if the Ruby VM has been shut down. There are
a couple of workarounds that I know of:
1. Setup an exit handler which sets a global variable (like I did in
https://github.com/tmm1/stackprof/pull/200).
2. In Ruby 2.4 thru 3.2, you could check the hidden `ruby_vm_global_ptr != NULL`.
For my use, in rb-sys there is a feature to automatically report Rust memory allocations
via `rb_gc_adjust_memory_usage`. However, there is a bug that can cause processes to
deadlock and/or segfault if a Rust destructor gets called after the VM quits (which can
happen in Rust background threads). Currently, I don’t think there’s a way to safely make
this feature work. (https://github.com/oxidize-rb/rb-sys/pull/205)
It would be nice to have an official way to know if the Ruby VM is available, basically
just a `ruby_current_vm_ptr != null`. Thoughts?
--
https://bugs.ruby-lang.org/
2 May
2 May
4:31 p.m.
New subject: [ruby-core:113393] [Ruby master Feature#19627] Add a way to detect if the Ruby VM is running in C API
Issue #19627 has been updated by mdalessio (Mike Dalessio).
I reported a related issue in https://bugs.ruby-lang.org/issues/19580 which I fixed with
https://github.com/ruby/ruby/pull/7663
Maybe you want to explore a similar fix which will short-circuit functions like
`rb_gc_adjust_memory_usage` instead of forcing callers to figure out if it's safe?
----------------------------------------
Feature #19627: Add a way to detect if the Ruby VM is running in C API
https://bugs.ruby-lang.org/issues/19627#change-102965
* Author: ianks (Ian Ker-Seymer)
* Status: Open
* Priority: Normal
----------------------------------------
Currently, there is no supported way to check if the Ruby VM has been shut down. There are
a couple of workarounds that I know of:
1. Setup an exit handler which sets a global variable (like I did in
https://github.com/tmm1/stackprof/pull/200).
2. In Ruby 2.4 thru 3.2, you could check the hidden `ruby_vm_global_ptr != NULL`.
For my use, in rb-sys there is a feature to automatically report Rust memory allocations
via `rb_gc_adjust_memory_usage`. However, there is a bug that can cause processes to
deadlock and/or segfault if a Rust destructor gets called after the VM quits (which can
happen in Rust background threads). Currently, I don’t think there’s a way to safely make
this feature work. (https://github.com/oxidize-rb/rb-sys/pull/205)
It would be nice to have an official way to know if the Ruby VM is available, basically
just a `ruby_current_vm_ptr != null`. Thoughts?
--
https://bugs.ruby-lang.org/
3 May
3 May
3:23 a.m.
New subject: [ruby-core:113397] [Ruby master Feature#19627] Add a way to detect if the Ruby VM is running in C API
Issue #19627 has been updated by ianks (Ian Ker-Seymer).
That’s a good idea. I’ll put a patch up for that.
So far I’ve encountered this issue this issue in `rb_gc_adjust_memory_usage` and
`rb_during_gc`, so I still think having the ability to check for a Ruby VM is important
for writing robust code. At the very least, it would provide an escape hatch in case there
are undiscovered edge cases lurking.
----------------------------------------
Feature #19627: Add a way to detect if the Ruby VM is running in C API
https://bugs.ruby-lang.org/issues/19627#change-102968
* Author: ianks (Ian Ker-Seymer)
* Status: Open
* Priority: Normal
----------------------------------------
Currently, there is no supported way to check if the Ruby VM has been shut down. There are
a couple of workarounds that I know of:
1. Setup an exit handler which sets a global variable (like I did in
https://github.com/tmm1/stackprof/pull/200).
2. In Ruby 2.4 thru 3.2, you could check the hidden `ruby_vm_global_ptr != NULL`.
For my use, in rb-sys there is a feature to automatically report Rust memory allocations
via `rb_gc_adjust_memory_usage`. However, there is a bug that can cause processes to
deadlock and/or segfault if a Rust destructor gets called after the VM quits (which can
happen in Rust background threads). Currently, I don’t think there’s a way to safely make
this feature work. (https://github.com/oxidize-rb/rb-sys/pull/205)
It would be nice to have an official way to know if the Ruby VM is available, basically
just a `ruby_current_vm_ptr != null`. Thoughts?
--
https://bugs.ruby-lang.org/
4:01 a.m.
New subject: [ruby-core:113398] [Ruby master Feature#19627] Add a way to detect if the Ruby VM is running in C API
Issue #19627 has been updated by ianks (Ian Ker-Seymer).
For documentations sake, [he's a real world reproduction of this issue that happens
when calling TLS
destructors](https://github.com/bytecodealliance/wasmtime-rb/actions/runs/4….
In Ruby < 3.3-dev, I'm able to avoid this by checking the hidden
`ruby_current_vm_ptr` symbol so the code won't segfault after VM shutdown.
```
-- C level backtrace information -------------------------------------------
/home/runner/.rubies/ruby-head/lib/libruby.so.3.3(rb_print_backtrace+0xd) [0x7f360aab3a3f]
/home/runner/work/ruby-dev-builder/ruby-dev-builder/vm_dump.c:785
/home/runner/.rubies/ruby-head/lib/libruby.so.3.3(rb_vm_bugreport)
/home/runner/work/ruby-dev-builder/ruby-dev-builder/vm_dump.c:1101
/home/runner/.rubies/ruby-head/lib/libruby.so.3.3(rb_bug_for_fatal_signal+0xf4)
[0x7f360a8b8c94] /home/runner/work/ruby-dev-builder/ruby-dev-builder/error.c:814
/home/runner/.rubies/ruby-head/lib/libruby.so.3.3(sigsegv+0x4d) [0x7f360a9feecd]
/home/runner/work/ruby-dev-builder/ruby-dev-builder/signal.c:964
/lib/x86_64-linux-gnu/libc.so.6(0x7f360a413520) [0x7f360a413520]
/home/runner/.rubies/ruby-head/lib/libruby.so.3.3(rb_gc_adjust_memory_usage+0xe)
[0x7f360a8dedbe] /home/runner/work/ruby-dev-builder/ruby-dev-builder/gc.c:12743
/lib/x86_64-linux-gnu/libc.so.6(__call_tls_dtors+0x3f) [0x7f360a416d9f]
/lib/x86_64-linux-gnu/libc.so.6(0x7f360a4165c9) [0x7f360a4165c9]
/lib/x86_64-linux-gnu/libc.so.6(on_exit+0x20) [0x7f360a416610]
/lib/x86_64-linux-gnu/libc.so.6(0x7f360a3fad97) [0x7f360a3fad97]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x7f360a3fae40]
[0x55e16aa391d5]
```
----------------------------------------
Feature #19627: Add a way to detect if the Ruby VM is running in C API
https://bugs.ruby-lang.org/issues/19627#change-102969
* Author: ianks (Ian Ker-Seymer)
* Status: Open
* Priority: Normal
----------------------------------------
Currently, there is no supported way to check if the Ruby VM has been shut down. There are
a couple of workarounds that I know of:
1. Setup an exit handler which sets a global variable (like I did in
https://github.com/tmm1/stackprof/pull/200).
2. In Ruby 2.4 thru 3.2, you could check the hidden `ruby_vm_global_ptr != NULL`.
For my use, in rb-sys there is a feature to automatically report Rust memory allocations
via `rb_gc_adjust_memory_usage`. However, there is a bug that can cause processes to
deadlock and/or segfault if a Rust destructor gets called after the VM quits (which can
happen in Rust background threads). Currently, I don’t think there’s a way to safely make
this feature work. (https://github.com/oxidize-rb/rb-sys/pull/205)
It would be nice to have an official way to know if the Ruby VM is available, basically
just a `ruby_current_vm_ptr != null`. Thoughts?
--
https://bugs.ruby-lang.org/
383
days inactive
385
days old
3 comments
2 participants
participants (2)
-
ianks (Ian Ker-Seymer) -
mdalessio (Mike Dalessio)