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 C24B3C433EF for ; Mon, 13 Jun 2022 12:06:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358478AbiFMMGg (ORCPT ); Mon, 13 Jun 2022 08:06:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358891AbiFMME5 (ORCPT ); Mon, 13 Jun 2022 08:04:57 -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 7D13650442; Mon, 13 Jun 2022 03:57:56 -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 07B1DB80E5E; Mon, 13 Jun 2022 10:57:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E6F4C34114; Mon, 13 Jun 2022 10:57:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655117873; bh=S6CzGRvk0XLaPZ/CM67BXYd3ef5d7le9NEe512uq/sI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hUoWgmrV3MDVBnCXW4fWTlBr8FqSuTVF9eMVadMyBnrhpjJPRBbvzXbGRYQhcQkSq qInm6+95Bp5khXR2XyLZxyhGIo3jAuEh+PIuT4AdcmCumtz0adjfo/B7ERg++DKn/x r2cUeSXCxu89jMG4qVuJ003TDfK+bb8ZLZNuy8p4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guoqing Jiang , Xiaomeng Tong , Goldwyn Rodrigues , Song Liu Subject: [PATCH 4.19 163/287] md: fix an incorrect NULL check in does_sb_need_changing Date: Mon, 13 Jun 2022 12:09:47 +0200 Message-Id: <20220613094928.820110371@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094923.832156175@linuxfoundation.org> References: <20220613094923.832156175@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: stable@vger.kernel.org From: Xiaomeng Tong commit fc8738343eefc4ea8afb6122826dea48eacde514 upstream. The bug is here: if (!rdev) The list iterator value 'rdev' will *always* be set and non-NULL by rdev_for_each(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element found. Otherwise it will bypass the NULL check and lead to invalid memory access passing the check. To fix the bug, use a new variable 'iter' as the list iterator, while using the original variable 'rdev' as a dedicated pointer to point to the found element. Cc: stable@vger.kernel.org Fixes: 2aa82191ac36 ("md-cluster: Perform a lazy update") Acked-by: Guoqing Jiang Signed-off-by: Xiaomeng Tong Acked-by: Goldwyn Rodrigues Signed-off-by: Song Liu Signed-off-by: Greg Kroah-Hartman --- drivers/md/md.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -2443,14 +2443,16 @@ static void sync_sbs(struct mddev *mddev static bool does_sb_need_changing(struct mddev *mddev) { - struct md_rdev *rdev; + struct md_rdev *rdev = NULL, *iter; struct mdp_superblock_1 *sb; int role; /* Find a good rdev */ - rdev_for_each(rdev, mddev) - if ((rdev->raid_disk >= 0) && !test_bit(Faulty, &rdev->flags)) + rdev_for_each(iter, mddev) + if ((iter->raid_disk >= 0) && !test_bit(Faulty, &iter->flags)) { + rdev = iter; break; + } /* No good device found. */ if (!rdev)