[PATCH] null pointer check when setting volume

[wangxingchao2011@xxxxxxxxx (wangxingchao2011@xxxxxxxxx)]

From: xingchao <xingchao.wang@xxxxxxxxx>

some sound app based on pulseaudio get crashed when setting volume, the coredump
show it's null pointer in pa_operation_ref().

Signed-off-by: xingchao <xingchao.wang at intel.com>
---
 src/utils/pactl.c |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/utils/pactl.c b/src/utils/pactl.c
index 2eb0f25..487cd41 100644
--- a/src/utils/pactl.c
+++ b/src/utils/pactl.c
@@ -1036,6 +1036,7 @@ static void volume_relative_adjust(pa_cvolume *cv) {
 
 static void get_sink_volume_callback(pa_context *c, const pa_sink_info *i, int is_last, void *userdata) {
     pa_cvolume cv;
+	pa_operation *o;
 
     if (is_last < 0) {
         pa_log(_("Failed to get sink information: %s"), pa_strerror(pa_context_errno(c)));
@@ -1050,7 +1051,9 @@ static void get_sink_volume_callback(pa_context *c, const pa_sink_info *i, int i
 
     cv = i->volume;
     volume_relative_adjust(&cv);
-    pa_operation_unref(pa_context_set_sink_volume_by_name(c, sink_name, &cv, simple_callback, NULL));
+	o = pa_context_set_sink_volume_by_name(c, sink_name, &cv, simple_callback, NULL);
+	if (o)
+	    pa_operation_unref(o);
 }
 
 static void get_source_volume_callback(pa_context *c, const pa_source_info *i, int is_last, void *userdata) {
@@ -1370,7 +1373,10 @@ static void context_state_callback(pa_context *c, void *userdata) {
                     } else {
                         pa_cvolume v;
                         pa_cvolume_set(&v, 1, volume);
-                        pa_operation_unref(pa_context_set_sink_volume_by_name(c, sink_name, &v, simple_callback, NULL));
+						pa_operation *o = pa_context_set_sink_volume_by_name(c, sink_name, &v, simple_callback, NULL);
+
+						if (o)
+	                        pa_operation_unref(o);
                     }
                     break;
 
-- 
1.7.1