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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 287F9C433F5 for ; Wed, 10 Nov 2021 18:43:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 088146115A for ; Wed, 10 Nov 2021 18:43:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230340AbhKJSq0 (ORCPT ); Wed, 10 Nov 2021 13:46:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:45534 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229969AbhKJSqZ (ORCPT ); Wed, 10 Nov 2021 13:46:25 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3E6BB61178; Wed, 10 Nov 2021 18:43:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636569817; bh=/iQuK9K/KkPDuVfiwxdOv+6xwNSc4aethQgwMj+8Nhw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c/Yf3OxVpRiNVuQ7Ohkyey26CGk3yPs2bGcKL2HiBXtgqWMEebct9oPUiCo9OgCRq vrSOX6qxJt93mwuInGj1C7palEbOuHDi78ONd+ElF9sH1RFEYd7VxTHpwLBxUVCaWF bfvhCsP8Nyipt6d1Z7S9eMTZCCcs/JY8Fd5oHaI8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Changhui Zhong , Yi Zhang , Ming Lei , "Martin K. Petersen" Subject: [PATCH 4.4 01/19] scsi: core: Put LLD module refcnt after SCSI device is released Date: Wed, 10 Nov 2021 19:43:03 +0100 Message-Id: <20211110182001.305943812@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211110182001.257350381@linuxfoundation.org> References: <20211110182001.257350381@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore 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: Ming Lei commit f2b85040acec9a928b4eb1b57a989324e8e38d3f upstream. SCSI host release is triggered when SCSI device is freed. We have to make sure that the low-level device driver module won't be unloaded before SCSI host instance is released because shost->hostt is required in the release handler. Make sure to put LLD module refcnt after SCSI device is released. Fixes a kernel panic of 'BUG: unable to handle page fault for address' reported by Changhui and Yi. Link: https://lore.kernel.org/r/20211008050118.1440686-1-ming.lei@redhat.com Cc: Greg Kroah-Hartman Reported-by: Changhui Zhong Reported-by: Yi Zhang Tested-by: Yi Zhang Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/scsi.c | 4 +++- drivers/scsi/scsi_sysfs.c | 9 +++++++++ 2 files changed, 12 insertions(+), 1 deletion(-) --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -936,8 +936,10 @@ EXPORT_SYMBOL(scsi_device_get); */ void scsi_device_put(struct scsi_device *sdev) { - module_put(sdev->host->hostt->module); + struct module *mod = sdev->host->hostt->module; + put_device(&sdev->sdev_gendev); + module_put(mod); } EXPORT_SYMBOL(scsi_device_put); --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -396,9 +396,12 @@ static void scsi_device_dev_release_user struct device *parent; struct list_head *this, *tmp; unsigned long flags; + struct module *mod; sdev = container_of(work, struct scsi_device, ew.work); + mod = sdev->host->hostt->module; + scsi_dh_release_device(sdev); parent = sdev->sdev_gendev.parent; @@ -430,11 +433,17 @@ static void scsi_device_dev_release_user if (parent) put_device(parent); + module_put(mod); } static void scsi_device_dev_release(struct device *dev) { struct scsi_device *sdp = to_scsi_device(dev); + + /* Set module pointer as NULL in case of module unloading */ + if (!try_module_get(sdp->host->hostt->module)) + sdp->host->hostt->module = NULL; + execute_in_process_context(scsi_device_dev_release_usercontext, &sdp->ew); }