From patchwork Sun Mar 27 08:01:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaomeng Tong X-Patchwork-Id: 554958 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 E7412C433F5 for ; Sun, 27 Mar 2022 08:01:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232312AbiC0IC7 (ORCPT ); Sun, 27 Mar 2022 04:02:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229636AbiC0IC6 (ORCPT ); Sun, 27 Mar 2022 04:02:58 -0400 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D554237A1C; Sun, 27 Mar 2022 01:01:19 -0700 (PDT) Received: by mail-pg1-x52e.google.com with SMTP id b130so8458220pga.13; Sun, 27 Mar 2022 01:01:19 -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=ZnZllXXln8alDD0gXRFXPDmFsbfIdQAqTJP0jTsTACA=; b=geUAslRO0BtqDXhocnaMIbdCadsDyrG8ccZGO0Hr5PrjxML36r1IdKo5wDwvVxbRDP mG9TQ/cPj6yX4sBuCAlUPgLMe21Cm2BGrN61dEL5xw1WxW26ka9Sp5/97HIVSLMVJFGu 1qzq7/Qg30OvKhbb/SceXje2tJKDV61vJHxqHp/OuB12kT1cqQwC1ufBtZY2JWXP4Jgg mteaB8DGleVPUxGtf4PS1/W2SW+PpU8lToiBwGpgF/rlu7DFY29641aeWyFkMJ+NCSuQ HAeN327L7B8MzZBjzrGmh1wDLpTPP6KWea6OGmav6CUbhHKlDSczB0qPqKWVylNqBw0w eFjw== 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=ZnZllXXln8alDD0gXRFXPDmFsbfIdQAqTJP0jTsTACA=; b=1ntrO4xqkNHDx55icE0SmApknpkoYFIoNvcbFHnLRk2S//m8GAHDyRsoPCDQHsXhUa v44/cBbKfxzdLOO0vwLY8/FnfOVOaR+6agJWEf6SFg2T6WUBfONGeqTGFsTxylh2yaqM 8uS/AdLFMMosfUSolDxawTv6MKsNBFw5fPv4356Ar4spKkfcQwestzE08nrEzR8r3zhd 22pawaU63W/NPUah4wS1kQIhUMNm/aRjjFpxD4/+rguk3Dy7vw5e8fhwk0YBA/ZoL2XE PYbpJr6VWbH/XC8vyGwx+qoVy4Z1v000h4YJNMmRTpT8ZVSMIQlGMB9FKOMDKcGzA/Yu JqsA== X-Gm-Message-State: AOAM532TbjpU/3d28bdnLDZKUpwVN8jYdb8UPWawBoGS4ja2eJKPQlyM BRhtDxasxVdpKq0ccMTiSu0= X-Google-Smtp-Source: ABdhPJzo9+5cGZaFGZrEkyN+iP/VR0lmUGxoh6a3CaaG8zNeL3g70vP72SiveDYhlHYyO4SN/UgJcQ== X-Received: by 2002:a63:d13:0:b0:381:f043:c627 with SMTP id c19-20020a630d13000000b00381f043c627mr6074836pgl.168.1648368079326; Sun, 27 Mar 2022 01:01:19 -0700 (PDT) Received: from localhost ([115.220.243.108]) by smtp.gmail.com with ESMTPSA id t7-20020a056a0021c700b004f7916d44bcsm11747823pfj.220.2022.03.27.01.01.18 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sun, 27 Mar 2022 01:01:18 -0700 (PDT) From: Xiaomeng Tong To: song@kernel.org, rgoldwyn@suse.com Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, Xiaomeng Tong , stable@vger.kernel.org Subject: [PATCH] md: md2: fix an incorrect NULL check on list iterator Date: Sun, 27 Mar 2022 16:01:11 +0800 Message-Id: <20220327080111.12028-1-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 (!rdev || rdev->desc_nr != nr) { The list iterator value 'rdev' will *always* be set and non-NULL by rdev_for_each_rcu(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element found (In fact, it will be a bogus pointer to an invalid struct object containing the HEAD). Otherwise it will bypass the check and lead to invalid memory access passing the check. To fix the bug, use a new variable 'iter' as the list iterator, while use the original variable 'pdev' as a dedicated pointer to point to the found element. Cc: stable@vger.kernel.org Fixes: 70bcecdb1534 ("amd-cluster: Improve md_reload_sb to be less error prone") Signed-off-by: Xiaomeng Tong --- drivers/md/md.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 7476fc204172..f156678c08bc 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9794,16 +9794,18 @@ static int read_rdev(struct mddev *mddev, struct md_rdev *rdev) void md_reload_sb(struct mddev *mddev, int nr) { - struct md_rdev *rdev; + struct md_rdev *rdev = NULL, *iter; int err; /* Find the rdev */ - rdev_for_each_rcu(rdev, mddev) { - if (rdev->desc_nr == nr) + rdev_for_each_rcu(iter, mddev) { + if (iter->desc_nr == nr) { + rdev = iter; break; + } } - if (!rdev || rdev->desc_nr != nr) { + if (!rdev) { pr_warn("%s: %d Could not find rdev with nr %d\n", __func__, __LINE__, nr); return; }