[Guile-commits] 04/08: Unlocked mutexes don't have owners

[Andy Wingo]

wingo pushed a commit to branch master
in repository guile.

commit 1ed9dea34aa8cb0cbae17200c31d1ac91a6a01de
Author: Andy Wingo <address@hidden>
Date:   Sun Nov 13 12:43:46 2016 +0100

    Unlocked mutexes don't have owners
    
    * libguile/threads.c (scm_unlock_mutex)
      (scm_timed_wait_condition_variable): Unlocked mutexes should never
      have owners.
---
 libguile/threads.c |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/libguile/threads.c b/libguile/threads.c
index 1c88796..863c84f 100644
--- a/libguile/threads.c
+++ b/libguile/threads.c
@@ -1268,8 +1268,11 @@ SCM_DEFINE (scm_unlock_mutex, "unlock-mutex", 1, 0, 0, 
(SCM mutex),
   if (m->level > 0)
     m->level--;
   if (m->level == 0)
-    /* Change the owner of MUTEX.  */
-    m->owner = unblock_from_queue (m->waiting);
+    /* Wake up one waiter.  */
+    {
+      m->owner = SCM_BOOL_F;
+      unblock_from_queue (m->waiting);
+    }
 
   scm_i_pthread_mutex_unlock (&m->lock);
 
@@ -1414,8 +1417,11 @@ SCM_DEFINE (scm_timed_wait_condition_variable, 
"wait-condition-variable", 2, 1,
       if (m->level > 0)
         m->level--;
       if (m->level == 0)
-        /* Change the owner of MUTEX.  */
-        m->owner = unblock_from_queue (m->waiting);
+        {
+          m->owner = SCM_BOOL_F;
+          /* Wake up one waiter.  */
+          unblock_from_queue (m->waiting);
+        }
 
       t->block_asyncs++;