mutex: Raise a ThreadError when detecting a fiber deadlock (#6680)
[Bug #19105]
If no fiber scheduler is registered and the fiber that
owns the lock and the one that try to acquire it
both belong to the same thread, we're in a deadlock case.
Co-authored-by: Jean Boussier <byroot@ruby-lang.org>
---
test/fiber/test_mutex.rb | 22 +++++++++++++++++++++-
thread_sync.c | 4 ++++
2 files changed, 25 insertions(+), 1 deletion(-)
mutex_mark is (basically) NULL, so we don't have any references to mark.
This means we should safely be able to mark Mutex as WB_PROTECTED
without changing anything else.
* Rename `rb_scheduler` to `rb_fiber_scheduler`.
* Use public interface if available.
* Use `rb_check_funcall` where possible.
* Don't use `unblock` unless the fiber was non-blocking.
When a scheduler is present, it's entirely possible for
`th->keeping_mutexes` to be updated while enumerating the waitq. Therefore
it must be fetched only during the removal operation.
* When there is a scheduler, the Fiber that would be blocked has already
been rescheduled and there is no point to interrupt something else.
That blocked Fiber will be rescheduled as the next call to the scheduler
(e.g., IO, sleep, other blocking sync).
* See discussion on d01954632d
* scheduler.unblock was already already called before but with no corresponding scheduler.block
* add test that Queue#pop makes the scheduler wait until it gets an element.
* Enables Mutex to be used as synchronization between multiple Fibers
of the same Thread.
* With a Fiber scheduler we can yield to another Fiber on contended
Mutex#lock instead of blocking the entire thread.
* This also makes the behavior of Mutex consistent across CRuby, JRuby and TruffleRuby.
* [Feature #16792]
This commit introduces Ractor mechanism to run Ruby program in
parallel. See doc/ractor.md for more details about Ractor.
See ticket [Feature #17100] to see the implementation details
and discussions.
[Feature #17100]
This commit does not complete the implementation. You can find
many bugs on using Ractor. Also the specification will be changed
so that this feature is experimental. You will see a warning when
you make the first Ractor with `Ractor.new`.
I hope this feature can help programmers from thread-safety issues.
After 5e86b005c0, I now think ANYARGS is
dangerous and should be extinct. This commit deletes ANYARGS from
rb_ensure, which also revealed many arity / type mismatches.
* internal.h (UNALIGNED_MEMBER_ACCESS, UNALIGNED_MEMBER_PTR):
moved from eval_intern.h.
* compile.c iseq.c, vm.c: use UNALIGNED_MEMBER_PTR for `entries`
in `struct iseq_catch_table`.
* vm_eval.c, vm_insnhelper.c: use UNALIGNED_MEMBER_PTR for `body`
in `rb_method_definition_t`.
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
... when clearing waitq. Otherwise, we risk redundantly clearing
valid waiters in future calls to `mutex_ptr`.
Note: I am not sure if this fixes [Bug #15430], and even if it
did, fork_gen is a belt-and-suspenders redundancy for [Bug #15383]
which wastes one word for every Mutex object.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66477 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
rb_mutex_abandon_all functions fine when passed a NULL value,
so let the compiler deal with the complexity of the branch
instead of the person reading the code.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66476 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Mutexes need to remain locked after forking.
This fixes "[BUG] invalid keeping_mutexes: Attempt to unlock a
mutex which is locked by another thread" and should
fix test_fork_while_parent_locked failures in CI
[ruby-core:90581] [Bug #15424]
[ruby-core:90595] [Bug #15430]
Fixes: r66230 ("handle mutexes held by parent threads in children")
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66438 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
