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 0AB18C43334 for ; Thu, 16 Jun 2022 08:10:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359623AbiFPIKc (ORCPT ); Thu, 16 Jun 2022 04:10:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1359243AbiFPIK3 (ORCPT ); Thu, 16 Jun 2022 04:10:29 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B42135D663 for ; Thu, 16 Jun 2022 01:10:26 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 36FFC1474; Thu, 16 Jun 2022 01:10:26 -0700 (PDT) Received: from [10.57.84.206] (unknown [10.57.84.206]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E16833F7F5; Thu, 16 Jun 2022 01:10:24 -0700 (PDT) Message-ID: <26872911-d9d2-3764-a579-ad60f8c8bfa5@arm.com> Date: Thu, 16 Jun 2022 09:10:23 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH] init: Initialize noop_backing_dev_info early To: Jan Kara , LKML Cc: Christoph Hellwig , Greg Kroah-Hartman , linux-mm@kvack.org, Guenter Roeck , Alexandru Elisei References: <20220615214815.6901-1-jack@suse.cz> From: Suzuki K Poulose In-Reply-To: <20220615214815.6901-1-jack@suse.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/06/2022 22:48, Jan Kara wrote: > noop_backing_dev_info is used by superblocks of various > pseudofilesystems such as kdevtmpfs. After commit 10e14073107d > ("writeback: Fix inode->i_io_list not be protected by inode->i_lock > error") this broke because __mark_inode_dirty() started to access more > fields from noop_backing_dev_info and this led to crashes inside > locked_inode_to_wb_and_lock_list() called from __mark_inode_dirty(). > Fix the problem by initializing noop_backing_dev_info before the > filesystems get mounted. > > Fixes: 10e14073107d ("writeback: Fix inode->i_io_list not be protected by inode->i_lock error") > Reported-by: Suzuki K Poulose > Reported-and-tested-by: Alexandru Elisei > Reported-and-tested-by: Guenter Roeck > Signed-off-by: Jan Kara Works for me too. Thanks for the proper fix Tested-by: Suzuki K Poulose > --- > drivers/base/init.c | 2 ++ > include/linux/backing-dev.h | 2 ++ > mm/backing-dev.c | 11 ++--------- > 3 files changed, 6 insertions(+), 9 deletions(-) > > Since this bug prevents some machines from booting, I plan to push this patch > to Linus unless someone objects soon... Review is welcome :). > > diff --git a/drivers/base/init.c b/drivers/base/init.c > index d8d0fe687111..397eb9880cec 100644 > --- a/drivers/base/init.c > +++ b/drivers/base/init.c > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > > #include "base.h" > > @@ -20,6 +21,7 @@ > void __init driver_init(void) > { > /* These are the core pieces */ > + bdi_init(&noop_backing_dev_info); > devtmpfs_init(); > devices_init(); > buses_init(); > diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h > index 2bd073fa6bb5..f0baef68f90f 100644 > --- a/include/linux/backing-dev.h > +++ b/include/linux/backing-dev.h > @@ -119,6 +119,8 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); > > extern struct backing_dev_info noop_backing_dev_info; > > +extern int bdi_init(struct backing_dev_info *bdi); > + > /** > * writeback_in_progress - determine whether there is writeback in progress > * @wb: bdi_writeback of interest > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > index ff60bd7d74e0..95550b8fa7fe 100644 > --- a/mm/backing-dev.c > +++ b/mm/backing-dev.c > @@ -231,20 +231,13 @@ static __init int bdi_class_init(void) > } > postcore_initcall(bdi_class_init); > > -static int bdi_init(struct backing_dev_info *bdi); > - > static int __init default_bdi_init(void) > { > - int err; > - > bdi_wq = alloc_workqueue("writeback", WQ_MEM_RECLAIM | WQ_UNBOUND | > WQ_SYSFS, 0); > if (!bdi_wq) > return -ENOMEM; > - > - err = bdi_init(&noop_backing_dev_info); > - > - return err; > + return 0; > } > subsys_initcall(default_bdi_init); > > @@ -781,7 +774,7 @@ static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb) > > #endif /* CONFIG_CGROUP_WRITEBACK */ > > -static int bdi_init(struct backing_dev_info *bdi) > +int bdi_init(struct backing_dev_info *bdi) > { > int ret; >