[runtime] Wait for the thread to really exit in Thread.Join (). (#5454)

diff --git a/mono/metadata/threads.c b/mono/metadata/threads.c
index 8eb4fe5f24e474e619a68bb2e17a00cb1f52f043..364316037ca17b9f85557d670013def2a30ed2dc 100644 (file)
--- a/mono/metadata/threads.c
+++ b/mono/metadata/threads.c
@@ -1801,7 +1801,7 @@ mono_join_uninterrupted (MonoThreadHandle* thread_to_join, gint32 ms, MonoError
 }
 
 gboolean
-ves_icall_System_Threading_Thread_Join_internal(MonoThread *this_obj, int ms)
+ves_icall_System_Threading_Thread_Join_internal (MonoThread *this_obj, int ms)
 {
        MonoInternalThread *thread = this_obj->internal_thread;
        MonoThreadHandle *handle = thread->handle;
@@ -1821,30 +1821,39 @@ ves_icall_System_Threading_Thread_Join_internal(MonoThread *this_obj, int ms)
                return FALSE;
        }
 
+       MonoNativeThreadId tid = thread_get_tid (thread);
+
        UNLOCK_THREAD (thread);
 
-       if(ms== -1) {
-               ms=MONO_INFINITE_WAIT;
-       }
+       if (ms == -1)
+               ms = MONO_INFINITE_WAIT;
        THREAD_DEBUG (g_message ("%s: joining thread handle %p, %d ms", __func__, handle, ms));
-       
+
        mono_thread_set_state (cur_thread, ThreadState_WaitSleepJoin);
 
-       ret=mono_join_uninterrupted (handle, ms, &error);
+       ret = mono_join_uninterrupted (handle, ms, &error);
 
        mono_thread_clr_state (cur_thread, ThreadState_WaitSleepJoin);
 
        mono_error_set_pending_exception (&error);
 
-       if(ret==MONO_THREAD_INFO_WAIT_RET_SUCCESS_0) {
+       if (ret == MONO_THREAD_INFO_WAIT_RET_SUCCESS_0) {
                THREAD_DEBUG (g_message ("%s: join successful", __func__));
 
-               return(TRUE);
+               /* Wait for the thread to really exit */
+               MONO_ENTER_GC_SAFE;
+               /* This shouldn't block */
+               mono_threads_join_lock ();
+               mono_native_thread_join (tid);
+               mono_threads_join_unlock ();
+               MONO_EXIT_GC_SAFE;
+
+               return TRUE;
        }
        
        THREAD_DEBUG (g_message ("%s: join failed", __func__));
 
-       return(FALSE);
+       return FALSE;
 }
 
 #define MANAGED_WAIT_FAILED 0x7fffffff