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 DF778C25B06 for ; Fri, 5 Aug 2022 01:37:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236091AbiHEBhJ (ORCPT ); Thu, 4 Aug 2022 21:37:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240662AbiHEBg3 (ORCPT ); Thu, 4 Aug 2022 21:36:29 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7ACF023BCB for ; Thu, 4 Aug 2022 18:36:26 -0700 (PDT) Received: from canpemm500005.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LzSkt5xldzWf8p; Fri, 5 Aug 2022 09:32:22 +0800 (CST) Received: from [10.174.178.134] (10.174.178.134) by canpemm500005.china.huawei.com (7.192.104.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 5 Aug 2022 09:36:23 +0800 Subject: Re: [PATCH v3 1/2] ext4: silence the warning when evicting inode with dioread_nolock To: CC: , , References: <20220629112647.4141034-1-yi.zhang@huawei.com> From: Zhang Yi Message-ID: <7701a2f8-5876-2795-4831-83a5d07eb70e@huawei.com> Date: Fri, 5 Aug 2022 09:36:23 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20220629112647.4141034-1-yi.zhang@huawei.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.134] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To canpemm500005.china.huawei.com (7.192.104.229) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Hi, Ted. Could you please pick up these two patches for 5.20? Thanks, Yi. On 2022/6/29 19:26, Zhang Yi wrote: > When evicting an inode with default dioread_nolock, it could be raced by > the unwritten extents converting kworker after writeback some new > allocated dirty blocks. It convert unwritten extents to written, the > extents could be merged to upper level and free extent blocks, so it > could mark the inode dirty again even this inode has been marked > I_FREEING. But the inode->i_io_list check and warning in > ext4_evict_inode() missing this corner case. Fortunately, > ext4_evict_inode() will wait all extents converting finished before this > check, so it will not lead to inode use-after-free problem, every thing > is OK besides this warning. The WARN_ON_ONCE was originally designed > for finding inode use-after-free issues in advance, but if we add > current dioread_nolock case in, it will become not quite useful, so fix > this warning by just remove this check. > > ====== > WARNING: CPU: 7 PID: 1092 at fs/ext4/inode.c:227 > ext4_evict_inode+0x875/0xc60 > ... > RIP: 0010:ext4_evict_inode+0x875/0xc60 > ... > Call Trace: > > evict+0x11c/0x2b0 > iput+0x236/0x3a0 > do_unlinkat+0x1b4/0x490 > __x64_sys_unlinkat+0x4c/0xb0 > do_syscall_64+0x3b/0x90 > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > RIP: 0033:0x7fa933c1115b > ====== > > rm kworker > ext4_end_io_end() > vfs_unlink() > ext4_unlink() > ext4_convert_unwritten_io_end_vec() > ext4_convert_unwritten_extents() > ext4_map_blocks() > ext4_ext_map_blocks() > ext4_ext_try_to_merge_up() > __mark_inode_dirty() > check !I_FREEING > locked_inode_to_wb_and_lock_list() > iput() > iput_final() > evict() > ext4_evict_inode() > truncate_inode_pages_final() //wait release io_end > inode_io_list_move_locked() > ext4_release_io_end() > trigger WARN_ON_ONCE() > > Fixes: ceff86fddae8 ("ext4: Avoid freeing inodes on dirty list") > Signed-off-by: Zhang Yi > Reviewed-by: Jan Kara > --- > fs/ext4/inode.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 84c0eb55071d..702cc208689a 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -220,13 +220,13 @@ void ext4_evict_inode(struct inode *inode) > > /* > * For inodes with journalled data, transaction commit could have > - * dirtied the inode. Flush worker is ignoring it because of I_FREEING > - * flag but we still need to remove the inode from the writeback lists. > + * dirtied the inode. And for inodes with dioread_nolock, unwritten > + * extents converting worker could merge extents and also have dirtied > + * the inode. Flush worker is ignoring it because of I_FREEING flag but > + * we still need to remove the inode from the writeback lists. > */ > - if (!list_empty_careful(&inode->i_io_list)) { > - WARN_ON_ONCE(!ext4_should_journal_data(inode)); > + if (!list_empty_careful(&inode->i_io_list)) > inode_io_list_del(inode); > - } > > /* > * Protect us against freezing - iput() caller didn't have to have any >