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Groups > linux.kernel > #1303064

[PATCH 05/31] media: Media Controller fix to not let stream_count go negative

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Add a range check to not let the stream_count become negative.
Wthout this check, calls to stop pipeline when there is no active
pipeline will result in stream_count < 0 condition and lock and
preventing link state (activate/deactivate) changes. This will
happen from error leg in start pipeline interface.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
 drivers/media/media-entity.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index 6e02d19..78486a9 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -464,9 +464,12 @@ error:
 	media_entity_graph_walk_start(graph, entity_err);
 
 	while ((entity_err = media_entity_graph_walk_next(graph))) {
-		entity_err->stream_count--;
-		if (entity_err->stream_count == 0)
-			entity_err->pipe = NULL;
+		/* don't let the stream_count go negative */
+		if (entity->stream_count > 0) {
+			entity_err->stream_count--;
+			if (entity_err->stream_count == 0)
+				entity_err->pipe = NULL;
+		}
 
 		/*
 		 * We haven't increased stream_count further than this
@@ -498,9 +501,12 @@ void media_entity_pipeline_stop(struct media_entity *entity)
 	media_entity_graph_walk_start(graph, entity);
 
 	while ((entity = media_entity_graph_walk_next(graph))) {
-		entity->stream_count--;
-		if (entity->stream_count == 0)
-			entity->pipe = NULL;
+		/* don't let the stream_count go negative */
+		if (entity->stream_count > 0) {
+			entity->stream_count--;
+			if (entity->stream_count == 0)
+				entity->pipe = NULL;
+		}
 	}
 
 	if (!--pipe->streaming_count)
-- 
2.5.0

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Thread

[PATCH 00/31] Sharing media resources across ALSA and au0828 drivers  Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 21:40 +0100
  [PATCH 05/31] media: Media Controller fix to not let stream_count go negative Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 21:40 +0100
  [PATCH 01/31] uapi/media.h: Declare interface types for ALSA Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 21:40 +0100
  [PATCH 30/31] sound/usb: Check media device unregister progress state Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:00 +0100
  [PATCH 28/31] media: au0828 create link between ALSA Mixer and decoder Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:00 +0100
  [PATCH 04/31] media: Media Controller enable/disable source handler API Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:00 +0100
  [PATCH 31/31] media: au0828 change to check media device unregister progress state Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:00 +0100
  [PATCH 11/31] media: au8522 change to create MC pad for ALSA Audio Out Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:00 +0100
  [PATCH 29/31] media: track media device unregister in progress Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:00 +0100
  [PATCH 25/31] media: au0828 fix to not call media_device_unregister_entity_notify() Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:10 +0100
  [PATCH 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:10 +0100
    Re: [PATCH 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API Takashi Iwai <tiwai@suse.de> - 2016-01-07 16:50 +0100
      Re: [PATCH 26/31] sound/usb: Update ALSA driver to use Managed Media  Controller API Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-07 21:30 +0100
  [PATCH 27/31] sound/usb: Create media mixer function and control interface entities Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-06 22:10 +0100

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