From patchwork Mon Jul 12 15:57:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 12371481 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 6DD0FC07E99 for ; Mon, 12 Jul 2021 15:58:20 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3CE11611C1 for ; Mon, 12 Jul 2021 15:58:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3CE11611C1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BC00089D40; Mon, 12 Jul 2021 15:58:19 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id 0112989D40 for ; Mon, 12 Jul 2021 15:58:17 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1DEBB31B; Mon, 12 Jul 2021 08:58:17 -0700 (PDT) Received: from e112269-lin.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 86FDA3F774; Mon, 12 Jul 2021 08:58:15 -0700 (PDT) From: Steven Price To: Daniel Vetter , David Airlie , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann Subject: [PATCH] drm/of: free the iterator object on failure Date: Mon, 12 Jul 2021 16:57:58 +0100 Message-Id: <20210712155758.48286-1-steven.price@arm.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Biju Das , Laurent Pinchart , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Steven Price Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" When bailing out due to the sanity check the iterator value needs to be freed because the early return prevents for_each_child_of_node() from doing the dereference itself. Fixes: 4ee48cc5586b ("drm: of: Fix double-free bug") Signed-off-by: Steven Price --- drivers/gpu/drm/drm_of.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) Daniel's email[1] made me take a look at this function and it appears that for_each_child_of_node()'s interface had caused a bad bug fix due to the hidden reference counting in the iterator. [1] https://lore.kernel.org/r/YOxQ5TbkNrqCGBDJ%40phenom.ffwll.local diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index 197c57477344..997b8827fed2 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -331,8 +331,10 @@ static int drm_of_lvds_get_remote_pixels_type( * configurations by passing the endpoints explicitly to * drm_of_lvds_get_dual_link_pixel_order(). */ - if (!current_pt || pixels_type != current_pt) + if (!current_pt || pixels_type != current_pt) { + of_node_put(endpoint); return -EINVAL; + } } return pixels_type;