[libcamera-devel,v2,3/3] libcamerasrc: Fix deadlock on EOS
diff mbox series

Message ID 20210826132346.1238420-4-nicolas@ndufresne.ca
State Accepted
Commit d3be776654076f7048c4365190535c0a2c39ad51
Headers show
Series
  • Fix Gnome Cheese and multiple camera
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Commit Message

Nicolas Dufresne Aug. 26, 2021, 1:23 p.m. UTC 
From: Nicolas Dufresne <nicolas.dufresne@collabora.com>

It's not allowed in GStreamer to push events while holding the object
lock. This reduce the scope into which we hold the object lock. In
fact we don't need to protect against gst_task_resume() concurrency
when we stop the task as resume only do something if the task is paused.

This fixes a deadlock when running multiple instances of libcamerasrc
and closing one of the streaming window.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 src/gstreamer/gstlibcamerasrc.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Patch
diff mbox series 

diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
index bdd9f88c..2be44edd 100644
--- a/src/gstreamer/gstlibcamerasrc.cpp
+++ b/src/gstreamer/gstlibcamerasrc.cpp
@@ -312,12 +312,6 @@  gst_libcamera_src_task_run(gpointer user_data)
 	}
 
 	{
-		/*
-		 * Here we need to decide if we want to pause or stop the task. This
-		 * needs to happen in lock step with the callback thread which may want
-		 * to resume the task.
-		 */
-		GLibLocker lock(GST_OBJECT(self));
 		if (ret != GST_FLOW_OK) {
 			if (ret == GST_FLOW_EOS) {
 				g_autoptr(GstEvent) eos = gst_event_new_eos();
@@ -332,6 +326,12 @@  gst_libcamera_src_task_run(gpointer user_data)
 			return;
 		}
 
+		/*
+		 * Here we need to decide if we want to pause. This needs to
+		 * happen in lock step with the callback thread which may want
+		 * to resume the task and might push pending buffers.
+		 */
+		GLibLocker lock(GST_OBJECT(self));
 		bool do_pause = true;
 		for (GstPad *srcpad : state->srcpads_) {
 			if (gst_libcamera_pad_has_pending(srcpad)) {