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 6E9F9C433EF for ; Wed, 29 Jun 2022 10:17:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233286AbiF2KRx (ORCPT ); Wed, 29 Jun 2022 06:17:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230071AbiF2KRw (ORCPT ); Wed, 29 Jun 2022 06:17:52 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0E963A1AC for ; Wed, 29 Jun 2022 03:17:50 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 7C9F41FEE6; Wed, 29 Jun 2022 10:17:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1656497869; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HLV1mHJD3a3n2IKNcLDVn6u12vq6Wc7JX8PTEEN6wM4=; b=UEbwPbeQD0TFYYpaEKIba+0REb9+CaQjRgoyc2PQajE1Zh+r7Nzfdm8dGF63L/WIvjcQsy Vwtja4dvfqLRxo1T5P6zfzBvrDehWBRTcTexDoauedBdWXecklJtTgexzZt+hJWgaBQMyZ wIwBan1kYLI02TPRu1yTbrogTBiebnY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1656497869; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HLV1mHJD3a3n2IKNcLDVn6u12vq6Wc7JX8PTEEN6wM4=; b=fA0AiMU+AtYaIXGLg9CyTbUtIsDf5MSYp7cAjC3pCvKpPXHFXVYbP5zl06VC0ExF4JrOXr u0cPfxM1EUaUWYDQ== Received: from quack3.suse.cz (unknown [10.100.224.230]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 65B292C141; Wed, 29 Jun 2022 10:17:49 +0000 (UTC) Received: by quack3.suse.cz (Postfix, from userid 1000) id 16DEFA062F; Wed, 29 Jun 2022 12:17:49 +0200 (CEST) Date: Wed, 29 Jun 2022 12:17:49 +0200 From: Jan Kara To: Zhang Yi Cc: linux-ext4@vger.kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, yukuai3@huawei.com Subject: Re: [PATCH v2 1/2] ext4: silence the warning when evicting inode with dioread_nolock Message-ID: <20220629101749.zljoazab33mb2xqm@quack3> References: <20220629022940.2855538-1-yi.zhang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220629022940.2855538-1-yi.zhang@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Wed 29-06-22 10:29:39, 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 Thanks! The patch looks good. Feel free to add: Reviewed-by: Jan Kara Honza > > 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 > -- > 2.31.1 > -- Jan Kara SUSE Labs, CR