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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 B5519C43461 for ; Mon, 10 May 2021 12:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C7FE613C2 for ; Mon, 10 May 2021 12:02:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244714AbhEJMBv (ORCPT ); Mon, 10 May 2021 08:01:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:44342 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236123AbhEJLHi (ORCPT ); Mon, 10 May 2021 07:07:38 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4F47F61929; Mon, 10 May 2021 10:58:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620644298; bh=Agkfor2JJ8xKqz1pTeXsVwJ2SVEWtZETXnHRKdSlESE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rnwFk4uMxCssEF1jpNa7tx44ybpIvRD36/7q8IgV4QMf9lQJain40zhmJPdra4JVa 5ro3Vn0EOO7j6I0Jf6WcUOgaFW3xyNKJ55hKXOw83LXpe4wmBAVBl1NGLE5E593IL1 Azhd+CvTBDUN5HAZEuRVBWGpctgExGV0artqAK/8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiang Chen , Yicong Yang , Tudor Ambarus , Michael Walle Subject: [PATCH 5.12 025/384] mtd: spi-nor: core: Fix an issue of releasing resources during read/write Date: Mon, 10 May 2021 12:16:54 +0200 Message-Id: <20210510102015.700714672@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102014.849075526@linuxfoundation.org> References: <20210510102014.849075526@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: linux-kernel@vger.kernel.org From: Xiang Chen commit be94215be1ab19e5d38f50962f611c88d4bfc83a upstream. If rmmod the driver during read or write, the driver will release the resources which are used during read or write, so it is possible to refer to NULL pointer. Use the testcase "mtd_debug read /dev/mtd0 0xc00000 0x400000 dest_file & sleep 0.5;rmmod spi_hisi_sfc_v3xx.ko", the issue can be reproduced in hisi_sfc_v3xx driver. To avoid the issue, fill the interface _get_device and _put_device of mtd_info to grab the reference to the spi controller driver module, so the request of rmmod the driver is rejected before read/write is finished. Fixes: b199489d37b2 ("mtd: spi-nor: add the framework for SPI NOR") Signed-off-by: Xiang Chen Signed-off-by: Yicong Yang Signed-off-by: Tudor Ambarus Tested-by: Michael Walle Tested-by: Tudor Ambarus Reviewed-by: Michael Walle Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1617262486-4223-1-git-send-email-yangyicong@hisilicon.com Signed-off-by: Greg Kroah-Hartman --- drivers/mtd/spi-nor/core.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -3301,6 +3301,37 @@ static void spi_nor_resume(struct mtd_in dev_err(dev, "resume() failed\n"); } +static int spi_nor_get_device(struct mtd_info *mtd) +{ + struct mtd_info *master = mtd_get_master(mtd); + struct spi_nor *nor = mtd_to_spi_nor(master); + struct device *dev; + + if (nor->spimem) + dev = nor->spimem->spi->controller->dev.parent; + else + dev = nor->dev; + + if (!try_module_get(dev->driver->owner)) + return -ENODEV; + + return 0; +} + +static void spi_nor_put_device(struct mtd_info *mtd) +{ + struct mtd_info *master = mtd_get_master(mtd); + struct spi_nor *nor = mtd_to_spi_nor(master); + struct device *dev; + + if (nor->spimem) + dev = nor->spimem->spi->controller->dev.parent; + else + dev = nor->dev; + + module_put(dev->driver->owner); +} + void spi_nor_restore(struct spi_nor *nor) { /* restore the addressing mode */ @@ -3495,6 +3526,8 @@ int spi_nor_scan(struct spi_nor *nor, co mtd->_read = spi_nor_read; mtd->_suspend = spi_nor_suspend; mtd->_resume = spi_nor_resume; + mtd->_get_device = spi_nor_get_device; + mtd->_put_device = spi_nor_put_device; if (nor->params->locking_ops) { mtd->_lock = spi_nor_lock;