The true bug fork_gen was hiding was rb_mutex_abandon_locking_mutex
failing to unconditionally clear the waitq of mutexes it was
waiting on. So we fix rb_mutex_abandon_locking_mutex, instead,
and eliminate rb_mutex_cleanup_keeping_mutexes.
This commit was tested heavily on a single-core Pentium-M which
was my most reliable reproducer of the "crash.rb" script from
[Bug #15383]
thread_sync.c (rb_mutex_t): eliminate fork_gen
The true bug fork_gen was hiding was rb_mutex_abandon_locking_mutex
failing to unconditionally clear the waitq of mutexes it was
waiting on. So we fix rb_mutex_abandon_locking_mutex, instead,
and eliminate rb_mutex_cleanup_keeping_mutexes.
This commit was tested heavily on a single-core Pentium-M which
was my most reliable reproducer of the "crash.rb" script from
[Bug #15383]
[Bug #14578] [Bug #15383]
Note: [Bug #15430] turned out to be an entirely different
problem: RLIMIT_NPROC limit was hit on the CI VMs.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66489 b2dd03c8-39d4-4d8f-98ff-823fe69b080e