{"id":13496,"url":"https://patchwork.libcamera.org/api/patches/13496/?format=json","web_url":"https://patchwork.libcamera.org/patch/13496/","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":"<20210825211852.1207168-4-nicolas@ndufresne.ca>","date":"2021-08-25T21:18:52","name":"[libcamera-devel,v1,3/3] libcamerasrc: Fix deadlock on EOS","commit_ref":null,"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/13496/mbox/","series":[{"id":2396,"url":"https://patchwork.libcamera.org/api/series/2396/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=2396","date":"2021-08-25T21:18:49","name":"Fix Gnome Cheese and multiple camera","version":1,"mbox":"https://patchwork.libcamera.org/series/2396/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/13496/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/13496/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 DAB78BD87D\n\tfor ;\n\tWed, 25 Aug 2021 21:19:18 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id A80EF68891;\n\tWed, 25 Aug 2021 23:19:18 +0200 (CEST)","from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 4BAC9688AE\n\tfor ;\n\tWed, 25 Aug 2021 23:19:17 +0200 (CEST)","from [127.0.0.1] (localhost [127.0.0.1])\n\t(Authenticated sender: nicolas) with ESMTPSA id 895081F435D8"],"From":"Nicolas Dufresne ","To":"libcamera-devel@lists.libcamera.org","Date":"Wed, 25 Aug 2021 17:18:52 -0400","Message-Id":"<20210825211852.1207168-4-nicolas@ndufresne.ca>","X-Mailer":"git-send-email 2.31.1","In-Reply-To":"<20210825211852.1207168-1-nicolas@ndufresne.ca>","References":"<20210825211852.1207168-1-nicolas@ndufresne.ca>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH v1 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 \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","v1","3/3"]}