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{ "id": 3942, "url": "https://patchwork.libcamera.org/api/1.1/patches/3942/?format=api", "web_url": "https://patchwork.libcamera.org/patch/3942/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/1.1/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20200605090106.15424-8-paul.elder@ideasonboard.com>", "date": "2020-06-05T09:01:06", "name": "[libcamera-devel,v2,7/7] v4l2: v4l2_camera_proxy: Fix segfault on restarting streams", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": false, "hash": "24cea2ad09f34ec8d3cc1aab30b05deb0670fa70", "submitter": { "id": 17, "url": "https://patchwork.libcamera.org/api/1.1/people/17/?format=api", "name": "Paul Elder", "email": "paul.elder@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/3942/mbox/", "series": [ { "id": 956, "url": "https://patchwork.libcamera.org/api/1.1/series/956/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=956", "date": "2020-06-05T09:00:59", "name": "Support qv4l2 with v4l2-compat", "version": 2, "mbox": "https://patchwork.libcamera.org/series/956/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/3942/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/3942/checks/", "tags": {}, "headers": { "Return-Path": "<paul.elder@ideasonboard.com>", "Received": [ "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id F01946124F\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tFri, 5 Jun 2020 11:01:26 +0200 (CEST)", "from emerald.amanokami.net (fs76eef344.knge213.ap.nuro.jp\n\t[118.238.243.68])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id C7CC227C;\n\tFri, 5 Jun 2020 11:01:25 +0200 (CEST)" ], "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key; \n\tunprotected) header.d=ideasonboard.com\n\theader.i=@ideasonboard.com\n\theader.b=\"QDIG04Jd\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1591347686;\n\tbh=5qweElhF0wT6dCUQnqxn3x3FOoB0mlpHWKTIFoMp5eQ=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=QDIG04Jdn5sWHF+rciXkRtWNdVJz+CnRyalRSIPvwuP12n3/ByAxWoqvBNqnOFwHk\n\tlyqHzVPxgp3gzozEpbrQXog9m+E3OfE0UVmnpWb/MGh9WuB+/gPl8zftTuISbIDfJh\n\tEL6KhVqjYeiZHajzya89H+/FG+oePzNI+zWAabro=", "From": "Paul Elder <paul.elder@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Date": "Fri, 5 Jun 2020 18:01:06 +0900", "Message-Id": "<20200605090106.15424-8-paul.elder@ideasonboard.com>", "X-Mailer": "git-send-email 2.20.1", "In-Reply-To": "<20200605090106.15424-1-paul.elder@ideasonboard.com>", "References": "<20200605090106.15424-1-paul.elder@ideasonboard.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Subject": "[libcamera-devel] [PATCH v2 7/7] v4l2: v4l2_camera_proxy: Fix\n\tsegfault on restarting streams", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "X-List-Received-Date": "Fri, 05 Jun 2020 09:01:27 -0000" }, "content": "The V4L2 compatibility layer keeps track of the index of the next buffer\nto be dequeued, to handle VIDIOC_DQBUF. This index is set to 0 on\nstartup and incremented (modulo #frames), and is otherwise never reset.\nThis means that if the last handled frame index is not #frames-1, and\nthe stream is restarted without restarting libcamera and the V4L2\ncompatilibity layer, the buffer index number won't match with the\nlibcamera buffer index number, causing a segfault. Fix this by resetting\nthe current buffer index to zero on VIDIOC_STREAMON.\n\nSigned-off-by: Paul Elder <paul.elder@ideasonboard.com>\n\n---\nNew in v2\n---\n src/v4l2/v4l2_camera_proxy.cpp | 2 ++\n 1 file changed, 2 insertions(+)", "diff": "diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp\nindex 7ee4c0cb..059f3cbe 100644\n--- a/src/v4l2/v4l2_camera_proxy.cpp\n+++ b/src/v4l2/v4l2_camera_proxy.cpp\n@@ -465,6 +465,8 @@ int V4L2CameraProxy::vidioc_streamon(int *arg)\n \tif (!validateBufferType(*arg))\n \t\treturn -EINVAL;\n \n+\tcurrentBuf_ = 0;\n+\n \treturn vcam_->streamOn();\n }\n \n", "prefixes": [ "libcamera-devel", "v2", "7/7" ] }