From 324204969dba501413a9f62de983806a6fddd6a0 Mon Sep 17 00:00:00 2001
From: Arnaud Giersch <arnaud.giersch@univ-fcomte.fr>
Date: Mon, 30 Apr 2018 13:25:42 +0200
Subject: [PATCH] Be consistent and hold mutex in any case when returning from
 condition_t::timedwait().

---
 messages.cpp | 12 ++++++++----
 synchro.h    |  1 +
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/messages.cpp b/messages.cpp
index 6c9f3ec..70e2236 100644
--- a/messages.cpp
+++ b/messages.cpp
@@ -63,7 +63,7 @@ void message_queue::push(msg_task_t task)
 
 bool message_queue::pop(message*& msg, msg_host_t& from, double timeout)
 {
-    msg_task_t task;
+    msg_task_t task = nullptr;
     if (!queue.try_pop(task)) {
         if (timeout == 0.0)
             return false;
@@ -71,17 +71,21 @@ bool message_queue::pop(message*& msg, msg_host_t& from, double timeout)
         mutex.acquire();
         if (!queue.try_pop(task)) {
             XBT_DEBUG("waiting for a message to come");
+            bool hit_timeout;
             if (timeout > 0) {
-                if (!cond.timedwait(mutex, timeout))
-                    return false;
+                hit_timeout = !cond.timedwait(mutex, timeout);
             } else {
                 cond.wait(mutex);
+                hit_timeout = false;
             }
             bool pop_was_successful = queue.try_pop(task);
-            xbt_assert(pop_was_successful);
+            xbt_assert(hit_timeout || pop_was_successful);
         }
         mutex.release();
     }
+    if (task == nullptr)
+        return false;
+
     msg = static_cast<message*>(MSG_task_get_data(task));
     from = MSG_task_get_source(task);
     MSG_task_destroy(task);
diff --git a/synchro.h b/synchro.h
index 45e0901..fed9e87 100644
--- a/synchro.h
+++ b/synchro.h
@@ -32,6 +32,7 @@ public:
             if (e.category != timeout_error)
                 RETHROW;
             xbt_ex_free(e);
+            mutex.acquire();
             return false;       // got a timeout
         }
         return true;
-- 
2.39.5