Take VM lock around manipulation of fiber pool for vacant stacks
When creating fibers in multiple ractors at the same time there were
issues with the manipulation of this structure, causing segfaults.
I didn't add any tests for this because I'm making a more general
PR in the very near future to be able to run test methods (test-all suite)
inside multiple ractors at the same time. This is how this bug was
caught, running test/ruby/test_fiber.rb inside 10 ractors at once.
Take VM lock around manipulation of fiber pool for vacant stacks
When creating fibers in multiple ractors at the same time there were
issues with the manipulation of this structure, causing segfaults.
I didn't add any tests for this because I'm making a more general
PR in the very near future to be able to run test methods (test-all suite)
inside multiple ractors at the same time. This is how this bug was
caught, running test/ruby/test_fiber.rb inside 10 ractors at once.