[vlc-devel] [PATCH 3/3] dec: lock p_vout/p_aout when read from the DecoderThread

[Thomas Guillem]

Since these variables can be written from any thread from format_update()
callbacks.
---
 src/input/decoder.c | 59 +++++++++++++++++++++++++++++++++++++--------
 1 file changed, 49 insertions(+), 10 deletions(-)

diff --git a/src/input/decoder.c b/src/input/decoder.c
index 1fdc4fb7ed..e8e4c109ef 100644
--- a/src/input/decoder.c
+++ b/src/input/decoder.c
@@ -103,10 +103,11 @@ struct decoder_owner
     vlc_cond_t  wait_fifo; /* TODO: merge with wait_acknowledge */
     vlc_cond_t  wait_timed;
 
-    /* -- These variables need locking on write(only) -- */
+    /* These variables are written from the format_update() callbacks threads.
+     * They need locking when they are read from the DecoderThread (use
+     * dec_get_aout()/dec_get_vout() helpers). */
     audio_output_t *p_aout;
-
-    vout_thread_t   *p_vout;
+    vout_thread_t  *p_vout;
 
     /* -- Theses variables need locking on read *and* write -- */
     /* Preroll */
@@ -158,6 +159,24 @@ static inline struct decoder_owner *dec_get_owner( decoder_t *p_dec )
     return container_of( p_dec, struct decoder_owner, dec );
 }
 
+static audio_output_t *dec_get_aout( decoder_t *p_dec )
+{
+    struct decoder_owner *p_owner = dec_get_owner( p_dec );
+    vlc_mutex_lock( &p_owner->lock );
+    audio_output_t *p_aout = p_owner->p_aout ? vlc_object_hold( p_owner->p_aout ) : NULL;
+    vlc_mutex_unlock( &p_owner->lock );
+    return p_aout;
+}
+
+static vout_thread_t *dec_get_vout( decoder_t *p_dec )
+{
+    struct decoder_owner *p_owner = dec_get_owner( p_dec );
+    vlc_mutex_lock( &p_owner->lock );
+    vout_thread_t *p_vout = p_owner->p_vout ? vlc_object_hold( p_owner->p_vout ) : NULL;
+    vlc_mutex_unlock( &p_owner->lock );
+    return p_vout;
+}
+
 /**
  * Load a decoder module
  */
@@ -238,15 +257,17 @@ static int ReloadDecoder( decoder_t *p_dec, bool b_packetizer,
     if( reload == RELOAD_DECODER_AOUT )
     {
         assert( p_owner->fmt.i_cat == AUDIO_ES );
-        audio_output_t *p_aout = p_owner->p_aout;
 
         vlc_mutex_lock( &p_owner->lock );
+        audio_output_t *p_aout = p_owner->p_aout ? vlc_object_hold( p_owner->p_aout ) : NULL;
         p_owner->p_aout = NULL;
         vlc_mutex_unlock( &p_owner->lock );
+
         if( p_aout )
         {
             aout_DecDelete( p_aout );
             input_resource_PutAout( p_owner->p_resource, p_aout );
+            vlc_object_release( p_aout );
         }
     }
 
@@ -1538,13 +1559,25 @@ static void *DecoderThread( void *p_data )
             switch( p_dec->fmt_out.i_cat )
             {
                 case VIDEO_ES:
-                    if( p_owner->p_vout != NULL )
-                        vout_ChangePause( p_owner->p_vout, paused, date );
+                {
+                    vout_thread_t *p_vout = dec_get_vout( p_dec );
+                    if( p_vout != NULL )
+                    {
+                        vout_ChangePause( p_vout, paused, date );
+                        vlc_object_release( p_vout );
+                    }
                     break;
+                }
                 case AUDIO_ES:
-                    if( p_owner->p_aout != NULL )
-                        aout_DecChangePause( p_owner->p_aout, paused, date );
+                {
+                    audio_output_t *p_aout = dec_get_aout( p_dec );
+                    if( p_aout != NULL )
+                    {
+                        aout_DecChangePause( p_aout, paused, date );
+                        vlc_object_release( p_aout );
+                    }
                     break;
+                }
                 case SPU_ES:
                     break;
                 default:
@@ -1569,9 +1602,15 @@ static void *DecoderThread( void *p_data )
                 case VIDEO_ES:
                     break;
                 case AUDIO_ES:
-                    if( p_owner->p_aout != NULL )
-                        aout_DecChangeRate( p_owner->p_aout, rate );
+                {
+                    audio_output_t *p_aout = dec_get_aout( p_dec );
+                    if( p_aout != NULL )
+                    {
+                        aout_DecChangeRate( p_aout, rate );
+                        vlc_object_release( p_aout );
+                    }
                     break;
+                }
                 case SPU_ES:
                     break;
                 default:
-- 
2.17.0