add missing increment of nrunning for jl_adopt_thread

src/scheduler.c

@@ -32,7 +32,7 @@ static const int16_t sleeping_like_the_dead JL_UNUSED = 2;
 // a running count of how many threads are currently not_sleeping
 // plus a running count of the number of in-flight wake-ups
 // n.b. this may temporarily exceed jl_n_threads
-static _Atomic(int) nrunning = 1;
+static _Atomic(int) nrunning = 0;
 
 // invariant: No thread is ever asleep unless sleep_check_state is sleeping (or we have a wakeup signal pending).
 // invariant: Any particular thread is not asleep unless that thread's sleep_check_state is sleeping.
@@ -201,6 +201,20 @@ void jl_threadfun(void *arg)
 }
 
 
+
+void jl_init_thread_scheduler(jl_ptls_t ptls) JL_NOTSAFEPOINT
+{
+    uv_mutex_init(&ptls->sleep_lock);
+    uv_cond_init(&ptls->wake_signal);
+    // record that there is now another thread that may be used to schedule work
+    // we will decrement this again in scheduler_delete_thread, only slightly
+    // in advance of pthread_join (which hopefully itself also had been
+    // adopted by now and is included in nrunning too)
+    (void)jl_atomic_fetch_add_relaxed(&nrunning, 1);
+    // n.b. this is the only point in the code where we ignore the invariants on the ordering of nrunning
+    // since we are being initialized from foreign code, we could not necessarily have expected or predicted that to happen
+}
+
 int jl_running_under_rr(int recheck)
 {
 #ifdef _OS_LINUX_

src/threading.c

@@ -316,6 +316,7 @@ int jl_all_tls_states_size;
 static uv_cond_t cond;
 // concurrent reads are permitted, using the same pattern as mtsmall_arraylist
 // it is implemented separately because the API of direct jl_all_tls_states use is already widely prevalent
+void jl_init_thread_scheduler(jl_ptls_t ptls) JL_NOTSAFEPOINT;
 
 // return calling thread's ID
 JL_DLLEXPORT int16_t jl_threadid(void)
@@ -379,9 +380,7 @@ jl_ptls_t jl_init_threadtls(int16_t tid)
     ptls->bt_data = bt_data;
     small_arraylist_new(&ptls->locks, 0);
     jl_init_thread_heap(ptls);
-
-    uv_mutex_init(&ptls->sleep_lock);
-    uv_cond_init(&ptls->wake_signal);
+    jl_init_thread_scheduler(ptls);
 
     uv_mutex_lock(&tls_lock);
     if (tid == -1)