Received: by 2002:a05:6358:d09b:b0:dc:cd0c:909e with SMTP id jc27csp3163294rwb; Fri, 2 Dec 2022 23:36:36 -0800 (PST) X-Google-Smtp-Source: AA0mqf6w5V+dTCvKKvhjw7LF5d5RJDOFheAlrsd5f50buYUAyidYsMWhZEXZHpRuXkHjzIUVfcp9 X-Received: by 2002:a63:5a62:0:b0:476:ed2a:6215 with SMTP id k34-20020a635a62000000b00476ed2a6215mr49336778pgm.559.1670052995875; Fri, 02 Dec 2022 23:36:35 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1670052995; cv=none; d=google.com; s=arc-20160816; b=uFU+WqnXYmfuOp9ltZQ0hIZqOLgRM850wnKwwunXkBHzLTxb+DAV/KWJj32FX0uN2V 55eovLrfUJeyoa0ekQvM5Vt7Fde+gAADFH967oqaREBa10MY0A6MbTlEW05SFUmyA7Yd hcUBxDI80/Ne/8fgGnonKx9RsJYNrgnjA5CJAlmy5YE6uVxVIbb5ZNI28x6DPMi7q6QS KqX4pOsZvhz/KJZdSFQWr9ydAS/1xslucd5PlfjNGI4eOOpyGh6nZ3sz53kk/OZArrZV B3DaLsQNcXzY5iZ+U3tuoR6QXlnOiv/rJr3QUKwJzJ3dYUAfgXAPya6vM0trofgizDYN t/2A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:to:content-transfer-encoding:in-reply-to :mime-version:user-agent:date:message-id:from:references:cc:subject; bh=Ylmk25YhZmT6q9AVyU+Y9BvtF/28xLRsgsYpDJhCo6s=; b=FAMT1poZ7rI3Ya8Jiy4cqhT1XYlcihRCsixbWwPgsb1atXds4L4EL+eQbuH5c/PJXX oXRgu9Md1DMgMGT+l8Mxt3VEA0HLfCx9YagT0GVlFDun+TYbe/sp5cjeUUHyFc/9CB4K yhGuKa51pTueHcKEiO6so5bY+vtFhAXV+f+IBYhmLpf8rJOo5Y5qgo1NxiiVgSNLy+OS aV0RvuOgaffRSwZtfIgrxwAs+3sQ8HWpKcPrt8OcEN2vR55jUhSHBiovCaZDz/zKTDic YWDFFFHEppHiDP8Xy3oo4loVTbMKIeUATuwgOOk6/orTe/lFKj72ET+35sG107qfFON9 JfYQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id t69-20020a638148000000b004786a82654esi8398514pgd.155.2022.12.02.23.36.25; Fri, 02 Dec 2022 23:36:35 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231439AbiLCH2I (ORCPT + 83 others); Sat, 3 Dec 2022 02:28:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231164AbiLCH2F (ORCPT ); Sat, 3 Dec 2022 02:28:05 -0500 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 744A0632E for ; Fri, 2 Dec 2022 23:28:03 -0800 (PST) Received: from dggpemm500015.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4NPLx20plSz15Myn; Sat, 3 Dec 2022 15:27:18 +0800 (CST) Received: from [10.174.177.133] (10.174.177.133) by dggpemm500015.china.huawei.com (7.185.36.181) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 3 Dec 2022 15:28:01 +0800 Subject: Re: [RFC PATCH] gfs2: Fix missing cleanup quota in gfs2_put_super() CC: , , , , , References: <20221201115032.3540859-1-bobo.shaobowang@huawei.com> From: "Wangshaobo (bobo)" Message-ID: <5c66dbe3-5701-ba42-7933-73a31c2dc891@huawei.com> Date: Sat, 3 Dec 2022 15:28:00 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: <20221201115032.3540859-1-bobo.shaobowang@huawei.com> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.133] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500015.china.huawei.com (7.185.36.181) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-3.4 required=5.0 tests=BAYES_00,MISSING_HEADERS, NICE_REPLY_A,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ?? 2022/12/1 19:50, Wang ShaoBo ะด??: > syzbot has reported an interesting issue: > > INFO: task syz-executor888:3126 blocked for more than 143 seconds. > Not tainted 6.1.0-rc6-syzkaller-32662-g6d464646530f #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:syz-executor888 state:D stack:0 pid:3126 ppid:3124 flags:0x00000000 > Call trace: > __switch_to+0x180/0x298 arch/arm64/kernel/process.c:553 > context_switch kernel/sched/core.c:5209 [inline] > __schedule+0x408/0x594 kernel/sched/core.c:6521 > schedule+0x64/0xa4 kernel/sched/core.c:6597 > schedule_timeout+0x108/0x1b4 kernel/time/timer.c:1935 > gfs2_gl_hash_clear+0xd4/0x1b0 fs/gfs2/glock.c:2263 > gfs2_put_super+0x318/0x390 fs/gfs2/super.c:620 > generic_shutdown_super+0x94/0x198 fs/super.c:492 > kill_block_super+0x30/0x78 fs/super.c:1428 > gfs2_kill_sb+0x68/0x78 > deactivate_locked_super+0x70/0xe8 fs/super.c:332 > deactivate_super+0xd0/0xd4 fs/super.c:363 > cleanup_mnt+0x184/0x1c0 fs/namespace.c:1186 > __cleanup_mnt+0x20/0x30 fs/namespace.c:1193 > task_work_run+0x100/0x148 kernel/task_work.c:179 > resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] > do_notify_resume+0x174/0x1f0 arch/arm64/kernel/signal.c:1127 > prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] > exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] > el0_svc+0x9c/0x150 arch/arm64/kernel/entry-common.c:638 > el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 > el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584 > > Showing all locks held in the system: > 1 lock held by rcu_tasks_kthre/11: > #0: ffff80000d4a4768 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x3c/0x450 kernel/rcu/tasks.h:507 > 1 lock held by rcu_tasks_trace/12: > #0: ffff80000d4a4db8 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x3c/0x450 kernel/rcu/tasks.h:507 > 1 lock held by khungtaskd/27: > #0: ffff80000d4a4640 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x4/0x48 include/linux/rcupdate.h:303 > 2 locks held by getty/2759: > #0: ffff0000c7d7e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x28/0x58 drivers/tty/tty_ldisc.c:244 > #1: ffff80000f6be2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x19c/0x89c drivers/tty/n_tty.c:2177 > 1 lock held by syz-executor888/3126: > #0: ffff0000cae680e0 (&type->s_umount_key#41){+.+.}-{3:3}, at: deactivate_super+0xc8/0xd4 fs/super.c:362 > > ============================================= > > One task blocked after executing gfs2_gl_hash_clear(), it looks > like go to sleep for waiting the condition (&sdp->sd_glock_disposal == 0), > this field sd_glock_disposal is used to count the getting times > that calling gfs2_glock_get() success, In most cases, when we operate > the mount interface, we will finally call this function: > > do_mount() > path_mount() > vfs_get_tree() > gfs2_get_tree() > get_tree_bdev() > gfs2_fill_super() > ________ init_inodes()_____________ > V V > gfs2_lookup_simple() gfs2_rindex_update() > gfs2_lookupi() gfs2_ri_update() > gfs2_dir_search() -> read_rindex_entry() //*gfs2_rgrpd->rd_gl > -> gfs2_inode_lookup() //*gfs2_inode->i_gl |__ gfs2_glock_get() > |__gfs2_glock_get() > > Correspondingly, release this glock's reference and decrease > sdp->sd_glock_disposal through this path when umount: > > cleanup_mnt() > deactivate_super() > deactivate_locked_super() > gfs2_kill_sb() > kill_block_super() > generic_shutdown_super() > _gfs2_rgrpd->rd_gl__gfs2_put_super()__gfs2_inode->i_gl__ > V V > gfs2_clear_rgrpd() gfs2_put_super() > gfs2_glock_put() iput() > gfs2_glock_free() evict() > gfs2_evict_inode() > gfs2_glock_put_eventually() > gfs2_glock_put() > gfs2_glock_free() > > But if calling reconfigure_super() from sysfs between mount and umount, > this path will also take the glock lock and increase sdp->sd_glock_disposal > as it also call gfs2_glock_get(): > > reconfigure_super() > gfs2_reconfigure() > gfs2_make_fs_rw() //remount filesystem read-write > gfs2_quota_init() > -> qd_alloc() //*gfs2_quota_data->qd_gl > |___ gfs2_glock_get() > > This relies on gfs2_quota_cleanup() that is eventually called by > gfs2_make_fs_ro() to clean up but unfortunately the file system > has not been remounted at this time, the condition (!sb_rdonly(sb)) > is false and gfs2_make_fs_ro() can not be called, ultimately makes > sdp->sd_glock_disposal never be 0. > > This add calling gfs2_quota_cleanup() when this filesystem remains > readOnly, in this case we don't need sync quota or other operation > otherwise the filesystem was really remounted. > > But this modification will trigger this warning: > > WARNING: CPU: 7 PID: 2595 at include/linux/backing-dev.h:246 __folio_mark_dirty+0x559/0x7b0 I paste wrong, the warning is: gfs2: fsid=mounts.0: warning: assertion "!qd->qd_change" failed at function = gfs2_quota_cleanup, file = fs/gfs2/quota.c, line = 1474 qd->qd_change has been changed in gfs2_quota_init(), but it looks we don't need to do anything before remounting the file system as read-write. > > We can filter this warning with adding a parameter as it doesn't > really make sense here. > > Fixes: 9e6e0a128bca ("GFS2: Merge mount.c and ops_super.c into super.c") > Reported-by: syzbot+ed7d0f71a89e28557a77@syzkaller.appspotmail.com > Signed-off-by: Wang ShaoBo > --- > fs/gfs2/super.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c > index b018957a1bb2..9a3c6da8db55 100644 > --- a/fs/gfs2/super.c > +++ b/fs/gfs2/super.c > @@ -586,7 +586,10 @@ static void gfs2_put_super(struct super_block *sb) > > if (!sb_rdonly(sb)) { > gfs2_make_fs_ro(sdp); > + } else { > + gfs2_quota_cleanup(sdp); > } > + > WARN_ON(gfs2_withdrawing(sdp)); > > /* At this point, we're through modifying the disk */ >