From patchwork Wed Feb 15 13:55:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 13141701 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 830ACC636CC for ; Wed, 15 Feb 2023 13:55:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229485AbjBONzt (ORCPT ); Wed, 15 Feb 2023 08:55:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbjBONzs (ORCPT ); Wed, 15 Feb 2023 08:55:48 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF6D94C2E for ; Wed, 15 Feb 2023 05:55:47 -0800 (PST) Received: from desky.lan (91-154-32-225.elisa-laajakaista.fi [91.154.32.225]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id CAF4810B; Wed, 15 Feb 2023 14:55:45 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1676469346; bh=R73N9LrFQgS92bAa3uQ8qsw8+GoyLqJ1/WfDyiyLI4o=; h=From:To:Cc:Subject:Date:From; b=Xc9JRjSbnzEpzCpY3rfIT7keyrGSrP11LmV+HVOxYTUGN8LPGIy2WoiEu2+zRo4pn tRlZT5uhbW/B+97ihRi+/I00u2EkxiOwto0GsUtf8oa+yGoMUMRperD8b5fC3SRioM lPAtwfdlXUXz6LxZ5icsYetflfobqADSSYIwb8UM= From: Tomi Valkeinen To: Laurent Pinchart , linux-media@vger.kernel.org, Hans Verkuil Cc: Tomi Valkeinen Subject: [PATCH] media: subdev: Fix backward compatibility with the new 'stream' field Date: Wed, 15 Feb 2023 15:55:23 +0200 Message-Id: <20230215135523.357332-1-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The new 'stream' field in many v4l2 structs was taken from reserved fields. The assumption was that the userspace is always required to zero initialize the whole struct. However, what happens in real life is that the apps only zero initialize the reserved fields/arrays. When such an app is compiled with new headers, the 'stream' field will be uninitialized, causing the kernel to (most likely) return an error. The streams API is still experimental and behind a compile-time flag, 'v4l2_subdev_enable_streams_api', and disabled by default. As a quick fix always set the 'stream' field to zero when that flag is not set. This keeps the backward compatibility when streams API is not enabled. A proper fix when streams support is enabled is something else. Somehow the userspace needs to signal the kernel that it actually intializes the 'stream' field. Signed-off-by: Tomi Valkeinen --- drivers/media/v4l2-core/v4l2-subdev.c | 33 +++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 1bebcda2bd20..efa0a7f770cf 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -609,6 +609,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, case VIDIOC_SUBDEV_G_FMT: { struct v4l2_subdev_format *format = arg; + if (!v4l2_subdev_enable_streams_api) + format->stream = 0; + memset(format->reserved, 0, sizeof(format->reserved)); memset(format->format.reserved, 0, sizeof(format->format.reserved)); return v4l2_subdev_call(sd, pad, get_fmt, state, format); @@ -620,6 +623,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, if (format->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev) return -EPERM; + if (!v4l2_subdev_enable_streams_api) + format->stream = 0; + memset(format->reserved, 0, sizeof(format->reserved)); memset(format->format.reserved, 0, sizeof(format->format.reserved)); return v4l2_subdev_call(sd, pad, set_fmt, state, format); @@ -629,6 +635,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, struct v4l2_subdev_crop *crop = arg; struct v4l2_subdev_selection sel; + if (!v4l2_subdev_enable_streams_api) + crop->stream = 0; + memset(crop->reserved, 0, sizeof(crop->reserved)); memset(&sel, 0, sizeof(sel)); sel.which = crop->which; @@ -650,6 +659,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, if (crop->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev) return -EPERM; + if (!v4l2_subdev_enable_streams_api) + crop->stream = 0; + memset(crop->reserved, 0, sizeof(crop->reserved)); memset(&sel, 0, sizeof(sel)); sel.which = crop->which; @@ -668,6 +680,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, case VIDIOC_SUBDEV_ENUM_MBUS_CODE: { struct v4l2_subdev_mbus_code_enum *code = arg; + if (!v4l2_subdev_enable_streams_api) + code->stream = 0; + memset(code->reserved, 0, sizeof(code->reserved)); return v4l2_subdev_call(sd, pad, enum_mbus_code, state, code); @@ -676,6 +691,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, case VIDIOC_SUBDEV_ENUM_FRAME_SIZE: { struct v4l2_subdev_frame_size_enum *fse = arg; + if (!v4l2_subdev_enable_streams_api) + fse->stream = 0; + memset(fse->reserved, 0, sizeof(fse->reserved)); return v4l2_subdev_call(sd, pad, enum_frame_size, state, fse); @@ -684,6 +702,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, case VIDIOC_SUBDEV_G_FRAME_INTERVAL: { struct v4l2_subdev_frame_interval *fi = arg; + if (!v4l2_subdev_enable_streams_api) + fi->stream = 0; + memset(fi->reserved, 0, sizeof(fi->reserved)); return v4l2_subdev_call(sd, video, g_frame_interval, arg); } @@ -694,6 +715,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, if (ro_subdev) return -EPERM; + if (!v4l2_subdev_enable_streams_api) + fi->stream = 0; + memset(fi->reserved, 0, sizeof(fi->reserved)); return v4l2_subdev_call(sd, video, s_frame_interval, arg); } @@ -701,6 +725,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, case VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL: { struct v4l2_subdev_frame_interval_enum *fie = arg; + if (!v4l2_subdev_enable_streams_api) + fie->stream = 0; + memset(fie->reserved, 0, sizeof(fie->reserved)); return v4l2_subdev_call(sd, pad, enum_frame_interval, state, fie); @@ -709,6 +736,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, case VIDIOC_SUBDEV_G_SELECTION: { struct v4l2_subdev_selection *sel = arg; + if (!v4l2_subdev_enable_streams_api) + sel->stream = 0; + memset(sel->reserved, 0, sizeof(sel->reserved)); return v4l2_subdev_call( sd, pad, get_selection, state, sel); @@ -720,6 +750,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, if (sel->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev) return -EPERM; + if (!v4l2_subdev_enable_streams_api) + sel->stream = 0; + memset(sel->reserved, 0, sizeof(sel->reserved)); return v4l2_subdev_call( sd, pad, set_selection, state, sel);