From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F8B83624D2 for ; Mon, 2 Mar 2026 11:54:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772452467; cv=pass; b=dgDsVARvEGxULyjzrw7yVl4i/G6/isaWmLkTi1rsPEgJE4sz1tXwcQZhoDi6PB2zifPlK4IMQTcapvYtz7gnDhK6LiAHeuRWcIVMopiOSiSVHG/Sjsy6UiNnNO4iK92bJnxuOekyq983a1ofz3myP6M9zkkG3mmqBe9O0HK/hM8= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772452467; c=relaxed/simple; bh=ND5pFcdx4lM5uOjhifx0fLfISZYw0Ff/yoxCl3VVgQU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lFWH3y4THPswu2lzkTTijkOgbuvzrTQ0HehR43OORR/c4iAy87pflBXK96CBB/N8AVhKVImaNmWEao4hbU+nsV78Ft8o6+ODohdJ5XfcpCvx4wfOQ3rOW0U0AS4EP7r/Ejmt6IyBPxu1THVXjeH05DKU27x5Jdd8zp6pxMUNjOE= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=dmitry.osipenko@collabora.com header.b=QKlP1oVh; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=dmitry.osipenko@collabora.com header.b="QKlP1oVh" ARC-Seal: i=1; a=rsa-sha256; t=1772452448; cv=none; d=zohomail.com; s=zohoarc; b=Qx/U5d4zq7OZvOUj4nlRjuBjA9abva6SrJxP0+mVkysUsjhh7cCjJhtiX0SjUffR/yuPSiN86DyYNxJ2eEQ7lui7Via1USBzmcoydPSwu+ijfwl1Vp8Rei9QBGbnzEHnlG/nGQVnh5Km+kGKkfNkBERuaa16P3vf9GR5OI8jn+0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1772452448; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=c7A0Webn6wO6R8jzqBsp6CdmNMvKUwy5JtEAW5UOr2k=; b=dqPoNkBdQl6fJndO5XkV9sNFLGGM/Oc7qLYAdKNkL3UmJ1r2kJ8Iwf3XPGIrJkOt43pHMsHeh/+0qudryIUWhLNAT4VgeAC2L1IItAU1JRlrgtI+MAcKFgdNqmfrAsPdvIF/Oydii4L+aWted6TnT2AmiMaP8mtF0afpLBy3I+0= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=dmitry.osipenko@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1772452448; s=zohomail; d=collabora.com; i=dmitry.osipenko@collabora.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:To:To:Cc:Cc:References:From:From:In-Reply-To:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=c7A0Webn6wO6R8jzqBsp6CdmNMvKUwy5JtEAW5UOr2k=; b=QKlP1oVhpUWft7FxPnXrl4uDChBo47m90bQjs+HdIExuFiqYCEY1RNGf3zMKnoiB hA6eC8qciAD2CgYUTFDuaFQXMQSxZOw2YvzCqDxHtVvMuHq09LcwqEFSip6DQZf7o/r yOrFtmKkQBE297fBqIwVG/1E9n/QvHRMAt6rKdtA= Received: by mx.zohomail.com with SMTPS id 17724524465011020.2808739219737; Mon, 2 Mar 2026 03:54:06 -0800 (PST) Message-ID: <75cdb128-2928-43e1-9a7f-e3c4dc40ee1b@collabora.com> Date: Mon, 2 Mar 2026 14:54:02 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/syncobj: Fix handle <-> fd ioctls with dirty stack To: =?UTF-8?Q?Christian_K=C3=B6nig?= , Julian Orth , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Clark Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20260301-point-v1-1-21fc5fd98614@gmail.com> <93f2c5b5-4f5e-46f1-a7f3-c388ab762592@amd.com> From: Dmitry Osipenko Content-Language: en-US In-Reply-To: <93f2c5b5-4f5e-46f1-a7f3-c388ab762592@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ZohoMailClient: External On 3/2/26 14:27, Christian König wrote: > On 3/1/26 13:34, Julian Orth wrote: >> Consider the following application: >> >> #include >> #include >> #include >> #include >> >> int main(void) { >> int fd = open("/dev/dri/renderD128", O_RDWR); >> struct drm_syncobj_create arg1; >> ioctl(fd, DRM_IOCTL_SYNCOBJ_CREATE, &arg1); >> struct drm_syncobj_handle arg2; >> memset(&arg2, 1, sizeof(arg2)); // simulate dirty stack >> arg2.handle = arg1.handle; >> arg2.flags = 0; >> arg2.fd = 0; >> arg2.pad = 0; >> // arg2.point = 0; // userspace is required to set point to 0 >> ioctl(fd, DRM_IOCTL_SYNCOBJ_HANDLE_TO_FD, &arg2); >> } >> >> The last ioctl returns EINVAL because args->point is not 0. However, >> userspace developed against older kernel versions is not aware of the >> new point field and might therefore not initialize it. >> >> The correct check would be >> >> if (args->flags & DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_TIMELINE) >> return -EINVAL; >> >> However, there might already be userspace that relies on this not >> returning an error as long as point == 0. Therefore use the more lenient >> check. >> >> Fixes: c2d3a7300695 ("drm/syncobj: Extend EXPORT_SYNC_FILE for timeline syncobjs") >> Signed-off-by: Julian Orth > > Good catch, Reviewed-by: Christian König > > As long as nobody objects I'm going to push this to drm-misc-fixes later today. No objections, thanks -- Best regards, Dmitry