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 B1C8FC04A68 for ; Wed, 27 Jul 2022 16:33:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237790AbiG0Qdr (ORCPT ); Wed, 27 Jul 2022 12:33:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237497AbiG0QdI (ORCPT ); Wed, 27 Jul 2022 12:33:08 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AE7C54AC4; Wed, 27 Jul 2022 09:26:30 -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 dfw.source.kernel.org (Postfix) with ESMTPS id EF36761A15; Wed, 27 Jul 2022 16:26:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 057F1C433C1; Wed, 27 Jul 2022 16:26:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939170; bh=SreVxgwI6lBZVdb5SSYKJ3fcMWrE/33Vzt8CofhLAp4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T/k9Zl93fb6IPvyHCi4hwX26/dxdbTysxky/Ikq0L+NKRNvAm34g92nUkPqhUjFyn EoSh4okYXgvlNStdtIcyPwQ/hjYG78cY8lJ7xKicb0FEFL8JzMggpEhFe12kypo8q5 78YMxAmAr5djyEWH3JuXovNbJZbexIn5n4be2LNQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiaomeng Tong , Jyri Sarha , Sasha Levin Subject: [PATCH 4.19 37/62] tilcdc: tilcdc_external: fix an incorrect NULL check on list iterator Date: Wed, 27 Jul 2022 18:10:46 +0200 Message-Id: <20220727161005.641385999@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161004.175638564@linuxfoundation.org> References: <20220727161004.175638564@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xiaomeng Tong [ Upstream commit 8b917cbe38e9b0d002492477a9fc2bfee2412ce4 ] The bug is here: if (!encoder) { The list iterator value 'encoder' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element is found. To fix the bug, use a new variable 'iter' as the list iterator, while use the original variable 'encoder' as a dedicated pointer to point to the found element. Cc: stable@vger.kernel.org Fixes: ec9eab097a500 ("drm/tilcdc: Add drm bridge support for attaching drm bridge drivers") Signed-off-by: Xiaomeng Tong Reviewed-by: Jyri Sarha Tested-by: Jyri Sarha Signed-off-by: Jyri Sarha Link: https://patchwork.freedesktop.org/patch/msgid/20220327061516.5076-1-xiam0nd.tong@gmail.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/tilcdc/tilcdc_external.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/tilcdc/tilcdc_external.c b/drivers/gpu/drm/tilcdc/tilcdc_external.c index a2f623550ce3..9c1be0635b53 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_external.c +++ b/drivers/gpu/drm/tilcdc/tilcdc_external.c @@ -60,11 +60,13 @@ struct drm_connector *tilcdc_encoder_find_connector(struct drm_device *ddev, int tilcdc_add_component_encoder(struct drm_device *ddev) { struct tilcdc_drm_private *priv = ddev->dev_private; - struct drm_encoder *encoder; + struct drm_encoder *encoder = NULL, *iter; - list_for_each_entry(encoder, &ddev->mode_config.encoder_list, head) - if (encoder->possible_crtcs & (1 << priv->crtc->index)) + list_for_each_entry(iter, &ddev->mode_config.encoder_list, head) + if (iter->possible_crtcs & (1 << priv->crtc->index)) { + encoder = iter; break; + } if (!encoder) { dev_err(ddev->dev, "%s: No suitable encoder found\n", __func__); -- 2.35.1