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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1662DE95A91 for ; Mon, 9 Oct 2023 13:29:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376907AbjJIN3p (ORCPT ); Mon, 9 Oct 2023 09:29:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376965AbjJIN3o (ORCPT ); Mon, 9 Oct 2023 09:29:44 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 138ADB7 for ; Mon, 9 Oct 2023 06:29:43 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54B2BC433C7; Mon, 9 Oct 2023 13:29:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696858182; bh=7T0C9GJetIV0Osyo8dafQ27MqvNtbaz9NPbr+iHyL/g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VXm6zMNYEYLC9qV0DeEH8rIw04TT5yV9hpngxIlF0Pbv8ViSXZtanqzescx5YMUEi OklGuhBVcpVnLjSXly6KWCPjn9zGoPX+/Jrmf7fmCl5euWhBcMwYXIZibFf29Fsq5J R0CwgkWOGBqqKb2VZ1sdphH8kmq81sMxx9BKFUaM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Aurabindo Pillai , Hamza Mahfooz , Alex Deucher , Sasha Levin Subject: [PATCH 5.4 041/131] drm/amd/display: prevent potential division by zero errors Date: Mon, 9 Oct 2023 15:01:21 +0200 Message-ID: <20231009130117.566299510@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130116.329529591@linuxfoundation.org> References: <20231009130116.329529591@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hamza Mahfooz [ Upstream commit 07e388aab042774f284a2ad75a70a194517cdad4 ] There are two places in apply_below_the_range() where it's possible for a divide by zero error to occur. So, to fix this make sure the divisor is non-zero before attempting the computation in both cases. Cc: stable@vger.kernel.org Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2637 Fixes: a463b263032f ("drm/amd/display: Fix frames_to_insert math") Fixes: ded6119e825a ("drm/amd/display: Reinstate LFC optimization") Reviewed-by: Aurabindo Pillai Signed-off-by: Hamza Mahfooz Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/modules/freesync/freesync.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c index 5835b968cac5d..ed5c9edfdcc56 100644 --- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c +++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c @@ -323,7 +323,9 @@ static void apply_below_the_range(struct core_freesync *core_freesync, * - Delta for CEIL: delta_from_mid_point_in_us_1 * - Delta for FLOOR: delta_from_mid_point_in_us_2 */ - if ((last_render_time_in_us / mid_point_frames_ceil) < in_out_vrr->min_duration_in_us) { + if (mid_point_frames_ceil && + (last_render_time_in_us / mid_point_frames_ceil) < + in_out_vrr->min_duration_in_us) { /* Check for out of range. * If using CEIL produces a value that is out of range, * then we are forced to use FLOOR. @@ -370,8 +372,9 @@ static void apply_below_the_range(struct core_freesync *core_freesync, /* Either we've calculated the number of frames to insert, * or we need to insert min duration frames */ - if (last_render_time_in_us / frames_to_insert < - in_out_vrr->min_duration_in_us){ + if (frames_to_insert && + (last_render_time_in_us / frames_to_insert) < + in_out_vrr->min_duration_in_us){ frames_to_insert -= (frames_to_insert > 1) ? 1 : 0; } -- 2.40.1