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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 A3859C4BA10 for ; Wed, 26 Feb 2020 11:11:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8292024689 for ; Wed, 26 Feb 2020 11:11:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728073AbgBZLLv (ORCPT ); Wed, 26 Feb 2020 06:11:51 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:38420 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728000AbgBZLLu (ORCPT ); Wed, 26 Feb 2020 06:11:50 -0500 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 81F038A282C020EE2566; Wed, 26 Feb 2020 19:11:45 +0800 (CST) Received: from huawei.com (10.90.53.225) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.439.0; Wed, 26 Feb 2020 19:11:41 +0800 From: Yufen Yu To: , , CC: , , , Subject: [PATCH v2 5/7] bfq: fix potential kernel crash when print dev err info Date: Wed, 26 Feb 2020 19:18:49 +0800 Message-ID: <20200226111851.55348-6-yuyufen@huawei.com> X-Mailer: git-send-email 2.16.2.dirty In-Reply-To: <20200226111851.55348-1-yuyufen@huawei.com> References: <20200226111851.55348-1-yuyufen@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.90.53.225] X-CFilter-Loop: Reflected Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org We use bdi_get_dev_name() to get device name, avoiding use-after-free or NULL pointer reference for ->dev. Signed-off-by: Yufen Yu --- block/bfq-iosched.c | 7 +++++-- include/linux/backing-dev.h | 2 ++ 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 00904611b8e4..8d41783d8e77 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -123,6 +123,7 @@ #include #include #include +#include #include "blk.h" #include "blk-mq.h" @@ -4971,6 +4972,7 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic) struct task_struct *tsk = current; int ioprio_class; struct bfq_data *bfqd = bfqq->bfqd; + char dname[BDI_DEV_NAME_LEN]; if (!bfqd) return; @@ -4978,8 +4980,9 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic) ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio); switch (ioprio_class) { default: - dev_err(&bfqq->bfqd->queue->backing_dev_info->rcu_dev->dev, - "bfq: bad prio class %d\n", ioprio_class); + bdi_get_dev_name(bfqq->bfqd->queue->backing_dev_info, + dname, BDI_DEV_NAME_LEN); + pr_err("bdi %s: bfq: bad prio class %d\n", dname, ioprio_class); /* fall through */ case IOPRIO_CLASS_NONE: /* diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 89d1cb7923f5..291db069f7da 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -19,6 +19,8 @@ #include #include +#define BDI_DEV_NAME_LEN 32 + static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi) { kref_get(&bdi->refcnt); -- 2.16.2.dirty