[sdb] Avoid stack overflows caused by recursive calls between suspend_current () and invoke_method (). (mono#13362)

Fixes mono#13261.

Author: vargaz

mono/mini/debugger-agent.c

@@ -3243,37 +3243,44 @@ suspend_current (void)
 	tls = (DebuggerTlsData *)mono_native_tls_get_value (debugger_tls_id);
 	g_assert (tls);
 
-	mono_coop_mutex_lock (&suspend_mutex);
+	gboolean do_resume = FALSE;
+	while (!do_resume) {
+		mono_coop_mutex_lock (&suspend_mutex);
 
-	tls->suspending = FALSE;
-	tls->really_suspended = TRUE;
+		tls->suspending = FALSE;
+		tls->really_suspended = TRUE;
 
-	if (!tls->suspended) {
-		tls->suspended = TRUE;
-		mono_coop_sem_post (&suspend_sem);
-	}
+		if (!tls->suspended) {
+			tls->suspended = TRUE;
+			mono_coop_sem_post (&suspend_sem);
+		}
 
-	DEBUG_PRINTF (1, "[%p] Suspended.\n", (gpointer) (gsize) mono_native_thread_id_get ());
+		DEBUG_PRINTF (1, "[%p] Suspended.\n", (gpointer) (gsize) mono_native_thread_id_get ());
 
-	while (suspend_count - tls->resume_count > 0) {
-		mono_coop_cond_wait (&suspend_cond, &suspend_mutex);
-	}
+		while (suspend_count - tls->resume_count > 0) {
+			mono_coop_cond_wait (&suspend_cond, &suspend_mutex);
+		}
 
-	tls->suspended = FALSE;
-	tls->really_suspended = FALSE;
+		tls->suspended = FALSE;
+		tls->really_suspended = FALSE;
 
-	threads_suspend_count --;
+		threads_suspend_count --;
 
-	mono_coop_mutex_unlock (&suspend_mutex);
+		mono_coop_mutex_unlock (&suspend_mutex);
 
-	DEBUG_PRINTF (1, "[%p] Resumed.\n", (gpointer) (gsize) mono_native_thread_id_get ());
+		DEBUG_PRINTF (1, "[%p] Resumed.\n", (gpointer) (gsize) mono_native_thread_id_get ());
 
-	if (tls->pending_invoke) {
-		/* Save the original context */
-		tls->pending_invoke->has_ctx = TRUE;
-		tls->pending_invoke->ctx = tls->context.ctx;
+		if (tls->pending_invoke) {
+			/* Save the original context */
+			tls->pending_invoke->has_ctx = TRUE;
+			tls->pending_invoke->ctx = tls->context.ctx;
 
-		invoke_method ();
+			invoke_method ();
+
+			/* Have to suspend again */
+		} else {
+			do_resume = TRUE;
+		}
 	}
 
 	/* The frame info becomes invalid after a resume */
@@ -8688,8 +8695,6 @@ invoke_method (void)
 
 	g_free (invoke->p);
 	g_free (invoke);
-
-	suspend_current ();
 }
 
 static gboolean