Re: Random crash when sending USR2 + QUIT signals to Unicorn process

[Eric Wong <e@80x24.org>]

+Cc: Philip and Jonathan  since they encountered this three years
ago, but we never heard back from them:

	https://bogomips.org/unicorn-public/?q=T_NODE+d:..20170713


Pere Joan Martorell <pere.joan@camaloon.com> wrote:
> > /home/deployer/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/unicorn-5.3.0/lib/unicorn/http_request.rb:80:in `parse': method `hash' called on unexpected T_NODE object (0x0055b15b973508 flags=0xaa31b) (NotImplementedError)

> Any idea what is happening?

This is most likely a bug in a C extension not using write
barriers correctly (perhaps via undocumented C-API functions in
Ruby).

I don't think I've seen this on ruby-core bug reports in a few years:

	https://public-inbox.org/ruby-core/?q=T_NODE

Fwiw, Appendix D on Generational GC in the Ruby source is
worth reading to any C extension authors:

	https://80x24.org/mirrors/ruby.git/plain/doc/extension.rdoc

There are probably build warnings when using some dangerous methods/macros,
maybe you can check build logs for const warnings.


Can you share the list of RubyGems you have loaded and maybe try
upgrading/replacing/eliminating the ones with C extensions
one-by-one until the error stops?

Also, perhaps the output of "pmap $PID_OF_WORKER" if you're on
Linux (or equivalent command if you're on another OS).

Anyways, I didn't notice anything suspicious in your config.

I'll do another self-audit of the unicorn + kgio + raindrops
extensions, too, but judging from the lack of reports and how
much they get used; I suspect the bug is elsewhere (more eyes
welcome, of course).

Thanks for the report and any more info you can provide!