From: Rémi Denis-Courmont <remi@remlab.net>
Date: Mon, 3 Aug 2009 16:35:37 +0000 (+0300)
Subject: vlc_timer_gettime: fix corner-case dead lock
X-Git-Tag: 1.1.0-ff~4593
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=1b9c3f12c850b65dc33d7d33bcaadcfdd128e84b;p=vlc

vlc_timer_gettime: fix corner-case dead lock

If vlc_cancel() while the timer thread is between mwait() and
vlc_mutex_lock(), a dead lock would occur at vlc_join(). We need to
release the timer lock first.
---

diff --git a/src/misc/pthread.c b/src/misc/pthread.c
index 47ac47831d..d31e38810b 100644
--- a/src/misc/pthread.c
+++ b/src/misc/pthread.c
@@ -812,11 +812,16 @@ void vlc_timer_destroy (vlc_timer_t timer)
 void vlc_timer_schedule (vlc_timer_t timer, bool absolute,
                          mtime_t value, mtime_t interval)
 {
+    static vlc_mutex_t lock = VLC_STATIC_MUTEX;
+
+    vlc_mutex_lock (&lock);
     vlc_mutex_lock (&timer->lock);
     if (timer->value)
     {
+        vlc_mutex_unlock (&timer->lock);
         vlc_cancel (timer->thread);
         vlc_join (timer->thread, NULL);
+        vlc_mutex_lock (&timer->lock);
         timer->value = 0;
     }
     if ((value != 0)
@@ -827,6 +832,7 @@ void vlc_timer_schedule (vlc_timer_t timer, bool absolute,
         timer->interval = interval;
     }
     vlc_mutex_unlock (&timer->lock);
+    vlc_mutex_unlock (&lock);
 }
 
 /**