From patchwork Sun Mar 27 06:15:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaomeng Tong X-Patchwork-Id: 554804 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 577EBC433F5 for ; Sun, 27 Mar 2022 06:15:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233416AbiC0GRD (ORCPT ); Sun, 27 Mar 2022 02:17:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233392AbiC0GRD (ORCPT ); Sun, 27 Mar 2022 02:17:03 -0400 Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [IPv6:2607:f8b0:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 451EC1F9; Sat, 26 Mar 2022 23:15:23 -0700 (PDT) Received: by mail-pf1-x432.google.com with SMTP id f3so8623663pfe.2; Sat, 26 Mar 2022 23:15:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id; bh=zQojn1+l5AZVyTtTxvOBeZeYl0iCp/EsKmxH0UlfEcs=; b=Hibwc5S0U7wcL6DejpbxHFA4lwtNZXXluK5w0lQDctDdwmhutQeqQBn0No39o26MwV gJG5BJCw1+UelUqn/tGXf3SFwVIPDpmpiPRSZ+u1sY3f6iqKckD719pRDZc973b4EXde R/a3pJSpYS6ro2qo3aZVIvSxfLYGAYktqScZAeFd0+/KnFt80DQVgCDhTtNBLGxmyS5T wgahD66mgtdWO8inc+hftRU9X4Zks5RVn+SEKX/vKLDEW+TKTNipJOxRacru4iMCdTcJ LKDDpszpxqgA1TWeikNnHOoZGSRFkAxqIpLH9InpiH+8DcW/Xg321+8hqxml1LWEvNuG 298Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=zQojn1+l5AZVyTtTxvOBeZeYl0iCp/EsKmxH0UlfEcs=; b=F18BhXXoV1/diYE1968mp/kwhzYQKCIvwfSeMnqG1pTgD277JTbVUGmEogeOljQVup ea4oWVDNG3wkRkwBnwC6N9n7byp02A7sE55gI4g4lRtb+3lQE9D5jWLBTymrdvsmQksn 0i/OK08aksti7OAzONjctDdn1DLC8HVzrHjsfUbJrAR3OPJwf1w9O02TzB03wCO0GxPU aJB1TP78VNlBOJQwU9ioGNJXNzxrRzIlF89eh/Ausp4qBJi3vmSzf7lufswrLQP7UEC7 BQnWTQ2+m7eaicChRkMJyneGWPYVgBMo/dWF7O37AuU70yLgJ6bse040MW7GqUXSbeXZ E6ng== X-Gm-Message-State: AOAM5301OkmcBRUDtiPsNBcW8qw+JkrPPsApm4DbYmg7dqru7mpnJyLe C4A55d8IEXB7FC3JeujS++k= X-Google-Smtp-Source: ABdhPJwA+6yTY8xKsO78Xv/GnGsfLJkWH/TmLye/R0ryZxaUbH2KjgQoftfUHWRZJBP0X7DIXlyr1g== X-Received: by 2002:a62:5583:0:b0:4fa:c74c:7eaa with SMTP id j125-20020a625583000000b004fac74c7eaamr17732239pfb.23.1648361722864; Sat, 26 Mar 2022 23:15:22 -0700 (PDT) Received: from localhost.localdomain ([115.220.243.108]) by smtp.googlemail.com with ESMTPSA id u204-20020a6279d5000000b004fa58625a80sm11650684pfc.53.2022.03.26.23.15.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Mar 2022 23:15:22 -0700 (PDT) From: Xiaomeng Tong To: jyri.sarha@iki.fi Cc: tomba@kernel.org, airlied@linux.ie, daniel@ffwll.ch, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Xiaomeng Tong , stable@vger.kernel.org Subject: [PATCH] tilcdc: tilcdc_external: fix an incorrect NULL check on list iterator Date: Sun, 27 Mar 2022 14:15:16 +0800 Message-Id: <20220327061516.5076-1-xiam0nd.tong@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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 --- 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 7594cf6e186e..3b86d002ef62 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__);