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 35546C3F6B0 for ; Thu, 25 Aug 2022 01:35:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232286AbiHYBfD (ORCPT ); Wed, 24 Aug 2022 21:35:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232437AbiHYBew (ORCPT ); Wed, 24 Aug 2022 21:34:52 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D90D1FCEF; Wed, 24 Aug 2022 18:34:51 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C319CB826E1; Thu, 25 Aug 2022 01:34:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F8B1C43144; Thu, 25 Aug 2022 01:34:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661391288; bh=i1COp1f4gJML2gGVKdwNYJvhMuBqUIl9UnbdTbXOiqU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XRXjCTojLg0iY1OgxF0uIjHi+haSBH5Ky9JgLvHnvNiJZN77GQBexW3aq+ZKN+Y0U TELAeiGRuYvCDd8F2cca0lCXKsFxTo2rvPkRaLN5xC5oJJ+0p+rYK1uY4Q90TTHttG ktVXmz28x0U8S9j2u6cguGOKWUyYiHbG9PtMIDfehvChUfp5o3Btc3uz5vicpCqdwu aHvzISaIMCAXYARTc3hjYOshszSc9A7ZDCWK7IYEe8RTR8O/cRNg2vf4tDs9pK4W/X IefWvXRpNhlCjXC3pa7Cth4NBOMdz8A8OZfZAFbWP2n5H1o9tuiNGoBBL2gZtA8HQZ /Ve50wuxjOgPg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Josip Pavic , Jun Lei , Alex Hung , Aric Cyr , Daniel Wheeler , Alex Deucher , Sasha Levin , harry.wentland@amd.com, sunpeng.li@amd.com, Rodrigo.Siqueira@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, airlied@linux.ie, daniel@ffwll.ch, isabbasso@riseup.net, jiapeng.chong@linux.alibaba.com, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 5.19 07/38] drm/amd/display: Avoid MPC infinite loop Date: Wed, 24 Aug 2022 21:33:30 -0400 Message-Id: <20220825013401.22096-7-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220825013401.22096-1-sashal@kernel.org> References: <20220825013401.22096-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josip Pavic [ Upstream commit 8de297dc046c180651c0500f8611663ae1c3828a ] [why] In some cases MPC tree bottom pipe ends up point to itself. This causes iterating from top to bottom to hang the system in an infinite loop. [how] When looping to next MPC bottom pipe, check that the pointer is not same as current to avoid infinite loop. Reviewed-by: Josip Pavic Reviewed-by: Jun Lei Acked-by: Alex Hung Signed-off-by: Aric Cyr Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c | 6 ++++++ drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c index 11019c2c62cc..8192f1967e92 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c +++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c @@ -126,6 +126,12 @@ struct mpcc *mpc1_get_mpcc_for_dpp(struct mpc_tree *tree, int dpp_id) while (tmp_mpcc != NULL) { if (tmp_mpcc->dpp_id == dpp_id) return tmp_mpcc; + + /* avoid circular linked list */ + ASSERT(tmp_mpcc != tmp_mpcc->mpcc_bot); + if (tmp_mpcc == tmp_mpcc->mpcc_bot) + break; + tmp_mpcc = tmp_mpcc->mpcc_bot; } return NULL; diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c index 15734db0cdea..f3c311d09319 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c @@ -531,6 +531,12 @@ static struct mpcc *mpc2_get_mpcc_for_dpp(struct mpc_tree *tree, int dpp_id) while (tmp_mpcc != NULL) { if (tmp_mpcc->dpp_id == 0xf || tmp_mpcc->dpp_id == dpp_id) return tmp_mpcc; + + /* avoid circular linked list */ + ASSERT(tmp_mpcc != tmp_mpcc->mpcc_bot); + if (tmp_mpcc == tmp_mpcc->mpcc_bot) + break; + tmp_mpcc = tmp_mpcc->mpcc_bot; } return NULL; -- 2.35.1