From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C17FC4338F for ; Tue, 24 Aug 2021 01:02:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FFCF61212 for ; Tue, 24 Aug 2021 01:02:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232634AbhHXBDZ (ORCPT ); Mon, 23 Aug 2021 21:03:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:48174 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233672AbhHXA5M (ORCPT ); Mon, 23 Aug 2021 20:57:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5C976613D0; Tue, 24 Aug 2021 00:55:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629766534; bh=/AxiVkp2wPOLGc5o1bO4R4KpoZShQ8u7g5ph4onMxvo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HMgOfcRnfgVeAVzCc2jpJxgF9lP6bsWfpzc9TAlO0HR0//6VV1UmyzajfMVwHbuVl okzAOkduIe5yoZYnyrD6t1zO29PaYkm4vOk3+f6eVViiqGQgnMbWydlgLp0JVHEIuO RT0DBigBZewPkNAbvl4gZNnpbRwxeGpDnX6DGMfkD0mQGPa390aF8xsK2jK6GErssK 7c0ihzCsPJAdCLIUNcRGrEizDOUUnMxocAbRn5aDImIxMj3QyzplvotFuzpChUJ6Hd RsYx0PpehMEdQQHDchO6+/EVyHaBVFNTKZWRMb+CJSDeqWHZ//SGxfl/dMZYTd/lGi o5PTPzjHTqhbw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Mark Yacoub , =?UTF-8?q?Michel=20D=C3=A4nzer?= , Mark Yacoub , Sean Paul , Sasha Levin , dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 4.14 4/7] drm: Copy drm_wait_vblank to user before returning Date: Mon, 23 Aug 2021 20:55:25 -0400 Message-Id: <20210824005528.631702-4-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210824005528.631702-1-sashal@kernel.org> References: <20210824005528.631702-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mark Yacoub [ Upstream commit fa0b1ef5f7a694f48e00804a391245f3471aa155 ] [Why] Userspace should get back a copy of drm_wait_vblank that's been modified even when drm_wait_vblank_ioctl returns a failure. Rationale: drm_wait_vblank_ioctl modifies the request and expects the user to read it back. When the type is RELATIVE, it modifies it to ABSOLUTE and updates the sequence to become current_vblank_count + sequence (which was RELATIVE), but now it became ABSOLUTE. drmWaitVBlank (in libdrm) expects this to be the case as it modifies the request to be Absolute so it expects the sequence to would have been updated. The change is in compat_drm_wait_vblank, which is called by drm_compat_ioctl. This change of copying the data back regardless of the return number makes it en par with drm_ioctl, which always copies the data before returning. [How] Return from the function after everything has been copied to user. Fixes IGT:kms_flip::modeset-vs-vblank-race-interruptible Tested on ChromeOS Trogdor(msm) Reviewed-by: Michel Dänzer Signed-off-by: Mark Yacoub Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20210812194917.1703356-1-markyacoub@chromium.org Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_ioc32.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c index 86105e7f07fc..6773e8f09fc3 100644 --- a/drivers/gpu/drm/drm_ioc32.c +++ b/drivers/gpu/drm/drm_ioc32.c @@ -855,8 +855,6 @@ static int compat_drm_wait_vblank(struct file *file, unsigned int cmd, req.request.sequence = req32.request.sequence; req.request.signal = req32.request.signal; err = drm_ioctl_kernel(file, drm_wait_vblank_ioctl, &req, DRM_UNLOCKED); - if (err) - return err; req32.reply.type = req.reply.type; req32.reply.sequence = req.reply.sequence; @@ -865,7 +863,7 @@ static int compat_drm_wait_vblank(struct file *file, unsigned int cmd, if (copy_to_user(argp, &req32, sizeof(req32))) return -EFAULT; - return 0; + return err; } #if defined(CONFIG_X86) -- 2.30.2