From 2c722f55894a716d48e75153bc376f82c80f94a6 Mon Sep 17 00:00:00 2001
From: Fay Carsons <faycarsons23@gmail.com>
Date: Sat, 20 Apr 2024 14:40:00 -0400
Subject: [PATCH] lock owner demonitor on unlock

---
 riot/lib/mutex.ml | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/riot/lib/mutex.ml b/riot/lib/mutex.ml
index 374c9b47..c8a15ae7 100644
--- a/riot/lib/mutex.ml
+++ b/riot/lib/mutex.ml
@@ -78,8 +78,7 @@ let selector = function
       `select m
   | _ -> `skip
 
-(* NOTE: (@faycarsons) Monitoring should(?) prevent deadlocks caused by mutex
-    process dying *)
+(* Monitor mutex process to catch crashes *)
 let wait_lock mutex : (unit, [> error ]) result =
   monitor mutex.process;
   send mutex.process @@ Lock (self ());
@@ -99,7 +98,9 @@ let try_wait_lock mutex =
 let wait_unlock mutex =
   send mutex.process @@ Unlock (self ());
   match[@warning "-8"] receive ~selector () with
-  | Unlock_accepted -> Ok ()
+  | Unlock_accepted ->
+      demonitor mutex.process;
+      Ok ()
   | Failed reason -> Error reason
   | Monitor (Process_down _) -> Error `process_died