{"id":13513,"url":"https://patchwork.libcamera.org/api/patches/13513/?format=json","web_url":"https://patchwork.libcamera.org/patch/13513/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20210826132346.1238420-4-nicolas@ndufresne.ca>","date":"2021-08-26T13:23:46","name":"[libcamera-devel,v2,3/3] libcamerasrc: Fix deadlock on EOS","commit_ref":"d3be776654076f7048c4365190535c0a2c39ad51","pull_url":null,"state":"accepted","archived":false,"hash":"1205a2fd40a2a0091f1b1bfab5e3c8123cb2170b","submitter":{"id":30,"url":"https://patchwork.libcamera.org/api/people/30/?format=json","name":"Nicolas Dufresne","email":"nicolas@ndufresne.ca"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/13513/mbox/","series":[{"id":2399,"url":"https://patchwork.libcamera.org/api/series/2399/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=2399","date":"2021-08-26T13:23:43","name":"Fix Gnome Cheese and multiple camera","version":2,"mbox":"https://patchwork.libcamera.org/series/2399/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/13513/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/13513/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 2BC7BC3242\n\tfor ;\n\tThu, 26 Aug 2021 13:24:05 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 42F9268921;\n\tThu, 26 Aug 2021 15:24:05 +0200 (CEST)","from bhuna.collabora.co.uk (bhuna.collabora.co.uk\n\t[IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 59ACD6890C\n\tfor ;\n\tThu, 26 Aug 2021 15:24:02 +0200 (CEST)","from [127.0.0.1] (localhost [127.0.0.1])\n\t(Authenticated sender: nicolas) with ESMTPSA id 7BA1A1F44332"],"From":"Nicolas Dufresne ","To":"libcamera-devel@lists.libcamera.org","Date":"Thu, 26 Aug 2021 09:23:46 -0400","Message-Id":"<20210826132346.1238420-4-nicolas@ndufresne.ca>","X-Mailer":"git-send-email 2.31.1","In-Reply-To":"<20210826132346.1238420-1-nicolas@ndufresne.ca>","References":"<20210826132346.1238420-1-nicolas@ndufresne.ca>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH v2 3/3] libcamerasrc: Fix deadlock on EOS","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"Nicolas Dufresne ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"From: Nicolas Dufresne \n\nIt's not allowed in GStreamer to push events while holding the object\nlock. This reduce the scope into which we hold the object lock. In\nfact we don't need to protect against gst_task_resume() concurrency\nwhen we stop the task as resume only do something if the task is paused.\n\nThis fixes a deadlock when running multiple instances of libcamerasrc\nand closing one of the streaming window.\n\nSigned-off-by: Nicolas Dufresne \nReviewed-by: Laurent Pinchart \n---\n src/gstreamer/gstlibcamerasrc.cpp | 12 ++++++------\n 1 file changed, 6 insertions(+), 6 deletions(-)","diff":"diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp\nindex bdd9f88c..2be44edd 100644\n--- a/src/gstreamer/gstlibcamerasrc.cpp\n+++ b/src/gstreamer/gstlibcamerasrc.cpp\n@@ -312,12 +312,6 @@ gst_libcamera_src_task_run(gpointer user_data)\n \t}\n \n \t{\n-\t\t/*\n-\t\t * Here we need to decide if we want to pause or stop the task. This\n-\t\t * needs to happen in lock step with the callback thread which may want\n-\t\t * to resume the task.\n-\t\t */\n-\t\tGLibLocker lock(GST_OBJECT(self));\n \t\tif (ret != GST_FLOW_OK) {\n \t\t\tif (ret == GST_FLOW_EOS) {\n \t\t\t\tg_autoptr(GstEvent) eos = gst_event_new_eos();\n@@ -332,6 +326,12 @@ gst_libcamera_src_task_run(gpointer user_data)\n \t\t\treturn;\n \t\t}\n \n+\t\t/*\n+\t\t * Here we need to decide if we want to pause. This needs to\n+\t\t * happen in lock step with the callback thread which may want\n+\t\t * to resume the task and might push pending buffers.\n+\t\t */\n+\t\tGLibLocker lock(GST_OBJECT(self));\n \t\tbool do_pause = true;\n \t\tfor (GstPad *srcpad : state->srcpads_) {\n \t\t\tif (gst_libcamera_pad_has_pending(srcpad)) {\n","prefixes":["libcamera-devel","v2","3/3"]}