Stopped threads from holding a reference to themselves. (#18636)

This caused a weird race condition, where if the owner of the thread
released it before it was even started, then the owner would continue
on, however only THEN would the thread actually start running at some
future time. It was also causing pthread_join to be called by the owning
thread.

This also fixes `deferred_action_queue` to not manually join the thread.

---------

Signed-off-by: Andrew Woloszyn <[email protected]>

Author: AWoloszyn

runtime/src/iree/base/internal/threading_darwin.c

@@ -77,10 +77,6 @@ static void* iree_thread_start_routine(void* param) {
   thread->entry = NULL;
   thread->entry_arg = NULL;
 
-  // Release our ownership of the thread handle. If the creating thread doesn't
-  // want it this will free the memory and fully detach the thread.
-  iree_thread_release(thread);
-
   // Call the user thread entry point function.
   // Note that this can be a tail-call which saves a stack frame in all threads
   // (which is really just to make call stacks in debuggers much cleaner).
@@ -128,9 +124,6 @@ iree_status_t iree_thread_create(iree_thread_entry_t entry, void* entry_arg,
   }
   pthread_attr_set_qos_class_np(&thread_attr, qos_class, 0);
 
-  // Retain the thread for the thread itself; this way if the caller immediately
-  // releases the iree_thread_t handle the thread won't explode.
-  iree_thread_retain(thread);
   *out_thread = thread;
 
   // Create the thread either suspended or running as the user requested.
@@ -148,7 +141,6 @@ iree_status_t iree_thread_create(iree_thread_entry_t entry, void* entry_arg,
   }
   pthread_attr_destroy(&thread_attr);
   if (rc != 0) {
-    iree_thread_release(thread);  // for self
     iree_thread_release(thread);  // for caller
     *out_thread = NULL;
     IREE_TRACE_ZONE_END(z0);

runtime/src/iree/base/internal/threading_pthreads.c

@@ -113,10 +113,6 @@ static void* iree_thread_start_routine(void* param) {
   thread->entry = NULL;
   thread->entry_arg = NULL;
 
-  // Release our ownership of the thread handle. If the creating thread doesn't
-  // want it this will free the memory and fully detach the thread.
-  iree_thread_release(thread);
-
   // Call the user thread entry point function.
   // Note that this can be a tail-call which saves a stack frame in all threads
   // (which is really just to make call stacks in debuggers much cleaner).
@@ -157,9 +153,6 @@ iree_status_t iree_thread_create(iree_thread_entry_t entry, void* entry_arg,
     pthread_attr_setstacksize(&thread_attr, params.stack_size);
   }
 
-  // Retain the thread for the thread itself; this way if the caller immediately
-  // releases the iree_thread_t handle the thread won't explode.
-  iree_thread_retain(thread);
   *out_thread = thread;
 
   // Unfortunately we can't create the thread suspended (no API). This means
@@ -176,7 +169,6 @@ iree_status_t iree_thread_create(iree_thread_entry_t entry, void* entry_arg,
   }
   pthread_attr_destroy(&thread_attr);
   if (rc != 0) {
-    iree_thread_release(thread);  // for self
     iree_thread_release(thread);  // for caller
     *out_thread = NULL;
     IREE_TRACE_ZONE_END(z0);

runtime/src/iree/base/internal/threading_win32.c

@@ -116,10 +116,6 @@ static DWORD WINAPI iree_thread_start_routine(LPVOID param) {
   thread->entry = NULL;
   thread->entry_arg = NULL;
 
-  // Release our ownership of the thread handle. If the creating thread doesn't
-  // want it this will free the memory and fully detach the thread.
-  iree_thread_release(thread);
-
   // Call the user thread entry point function.
   // Note that this can be a tail-call which saves a stack frame in all threads
   // (which is really just to make call stacks in debuggers much cleaner).
@@ -154,9 +150,6 @@ iree_status_t iree_thread_create(iree_thread_entry_t entry, void* entry_arg,
                                        params.priority_class, thread->allocator,
                                        &thread->qos_override_list);
 
-  // Retain the thread for the thread itself; this way if the caller immediately
-  // releases the iree_thread_t handle the thread won't explode.
-  iree_thread_retain(thread);
   *out_thread = thread;
 
   // Create the thread either suspended or running as the user requested.
@@ -169,7 +162,6 @@ iree_status_t iree_thread_create(iree_thread_entry_t entry, void* entry_arg,
   }
   if (thread->handle == INVALID_HANDLE_VALUE) {
     iree_thread_release(thread);  // for self
-    iree_thread_release(thread);  // for caller
     *out_thread = NULL;
     IREE_TRACE_ZONE_END(z0);
     return iree_make_status(IREE_STATUS_INTERNAL,

runtime/src/iree/hal/utils/deferred_work_queue.c

@@ -598,10 +598,7 @@ void iree_hal_deferred_work_queue_destroy(
   // Request the workers to exit.
   iree_hal_deferred_work_queue_request_exit(work_queue);
 
-  iree_thread_join(work_queue->worker_thread);
   iree_thread_release(work_queue->worker_thread);
-
-  iree_thread_join(work_queue->completion_thread);
   iree_thread_release(work_queue->completion_thread);
 
   iree_hal_deferred_work_queue_working_area_deinitialize(