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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6C3FC433E0 for ; Thu, 25 Feb 2021 04:40:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADDCF64ED3 for ; Thu, 25 Feb 2021 04:40:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232471AbhBYEkh (ORCPT ); Wed, 24 Feb 2021 23:40:37 -0500 Received: from eu-shark2.inbox.eu ([195.216.236.82]:48228 "EHLO eu-shark2.inbox.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232465AbhBYEkf (ORCPT ); Wed, 24 Feb 2021 23:40:35 -0500 Received: from eu-shark2.inbox.eu (localhost [127.0.0.1]) by eu-shark2-out.inbox.eu (Postfix) with ESMTP id DFEBC455DF5; Thu, 25 Feb 2021 06:39:46 +0200 (EET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=inbox.eu; s=20140211; t=1614227986; bh=hNOwWB1vx3TnW6HCVr5m9NG3BD9ExlWvrUI5S7bfTuo=; h=From:To:Cc:Subject:Date; b=kei76oXHjlyaNi8KynXNvpnoU5FMuYrZl87Wz7P2WA7FCUPXAudPI/rXsJXDIda0/ wIyWdI7bk4cQ4DKb6q63bGNfuSy1JiYBzUtpkvUgW2VMEhzuSWqxM73kkCSv/MVqhh 1hFxBBsPs9uB6Xt9dhIiGAbQhY3N/Wn6e1QgRyLw= Received: from localhost (localhost [127.0.0.1]) by eu-shark2-in.inbox.eu (Postfix) with ESMTP id CB0DE4594A5; Thu, 25 Feb 2021 06:39:46 +0200 (EET) Received: from eu-shark2.inbox.eu ([127.0.0.1]) by localhost (eu-shark2.inbox.eu [127.0.0.1]) (spamfilter, port 35) with ESMTP id D2P5pdsVivof; Thu, 25 Feb 2021 06:39:46 +0200 (EET) Received: from mail.inbox.eu (eu-pop1 [127.0.0.1]) by eu-shark2-in.inbox.eu (Postfix) with ESMTP id 3A8EF22A68; Thu, 25 Feb 2021 06:39:46 +0200 (EET) Received: from nas (unknown [45.87.95.231]) (Authenticated sender: l@damenly.su) by mail.inbox.eu (Postfix) with ESMTPA id 9E8A41BE009C; Thu, 25 Feb 2021 06:39:44 +0200 (EET) User-agent: mu4e 1.4.13; emacs 27.1 From: Su Yue To: Btrfs BTRFS Cc: Anand Jain Subject: [report] lockdep warning when mounting seed device Message-ID: Date: Thu, 25 Feb 2021 12:39:39 +0800 MIME-Version: 1.0 Content-Type: text/plain; format=flowed X-Virus-Scanned: OK X-ESPOL: +d1m7upSeE2piELYI3baABg/qDRAWfPn+Oamo2NU3CS6LUzwc0kLUBG1lW93SXqk Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org While playing with seed device(misc/next and v5.11), lockdep complains the following: To reproduce: dev1=/dev/sdb1 dev2=/dev/sdb2 umount /mnt mkfs.btrfs -f $dev1 btrfstune -S 1 $dev1 mount $dev1 /mnt btrfs device add $dev2 /mnt/ -f umount /mnt mount $dev2 /mnt umount /mnt Warning: [ 104.348749] BTRFS: device fsid 9a34d68b-fd18-470c-8cfc-44916c364c76 devid 1 transid 5 /dev/sdb1 scanned by mkfs.btrfs (627) [ 104.377243] BTRFS info (device sdb1): disk space caching is enabled [ 104.378091] BTRFS info (device sdb1): has skinny extents [ 104.378800] BTRFS info (device sdb1): flagging fs with big metadata feature [ 104.512522] BTRFS info (device sdb1): relocating block group 567279616 flags system|dup [ 104.535912] BTRFS info (device sdb1): relocating block group 22020096 flags system|dup [ 104.571307] BTRFS info (device sdb1): disk added /dev/sdb2 [ 104.602831] BTRFS info (device sdb2): disk space caching is enabled [ 104.603692] BTRFS info (device sdb2): has skinny extents [ 104.606389] ====================================================== [ 104.607212] WARNING: possible circular locking dependency detected [ 104.608025] 5.11.0-rc7-custom+ #55 Tainted: G O [ 104.608790] ------------------------------------------------------ [ 104.609599] mount/670 is trying to acquire lock: [ 104.610207] ffffa2274d7158e8 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: clone_fs_devices+0x4f/0x160 [btrfs] [ 104.611585] but task is already holding lock: [ 104.612334] ffffa22750e32f20 (btrfs-chunk-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x2d/0x110 [btrfs] [ 104.651264] which lock already depends on the new lock. [ 104.708041] the existing dependency chain (in reverse order) is: [ 104.743619] -> #1 (btrfs-chunk-00){++++}-{3:3}: [ 104.777693] down_read_nested+0x4b/0x140 [ 104.794386] __btrfs_tree_read_lock+0x2d/0x110 [btrfs] [ 104.811338] btrfs_read_lock_root_node+0x36/0x50 [btrfs] [ 104.828574] btrfs_search_slot+0x473/0x900 [btrfs] [ 104.845543] btrfs_update_device+0x71/0x1a0 [btrfs] [ 104.862164] btrfs_finish_chunk_alloc+0x121/0x490 [btrfs] [ 104.878474] btrfs_create_pending_block_groups+0x151/0x2c0 [btrfs] [ 104.894725] btrfs_commit_transaction+0x82/0xb30 [btrfs] [ 104.910808] btrfs_init_new_device+0x1015/0x14d0 [btrfs] [ 104.926879] btrfs_ioctl+0x1ff/0x2fc0 [btrfs] [ 104.942996] __x64_sys_ioctl+0x91/0xc0 [ 104.958874] do_syscall_64+0x38/0x50 [ 104.974554] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 104.990108] -> #0 (&fs_devs->device_list_mutex){+.+.}-{3:3}: [ 105.020508] __lock_acquire+0x11e0/0x1ea0 [ 105.035759] lock_acquire+0xd8/0x3c0 [ 105.050434] __mutex_lock+0x8f/0x870 [ 105.064614] mutex_lock_nested+0x1b/0x20 [ 105.078641] clone_fs_devices+0x4f/0x160 [btrfs] [ 105.092984] btrfs_read_chunk_tree+0x30e/0x7f0 [btrfs] [ 105.107031] open_ctree+0xb40/0x176a [btrfs] [ 105.120673] btrfs_mount_root.cold+0x12/0xeb [btrfs] [ 105.134564] legacy_get_tree+0x34/0x60 [ 105.148347] vfs_get_tree+0x2d/0xc0 [ 105.162053] vfs_kern_mount.part.0+0x78/0xc0 [ 105.176072] vfs_kern_mount+0x13/0x20 [ 105.189844] btrfs_mount+0x11f/0x3c0 [btrfs] [ 105.203396] legacy_get_tree+0x34/0x60 [ 105.217129] vfs_get_tree+0x2d/0xc0 [ 105.230536] path_mount+0x48c/0xd30 [ 105.243915] __x64_sys_mount+0x108/0x140 [ 105.257030] do_syscall_64+0x38/0x50 [ 105.270084] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 105.283382] other info that might help us debug this: [ 105.321699] Possible unsafe locking scenario: [ 105.347053] CPU0 CPU1 [ 105.359640] ---- ---- [ 105.372004] lock(btrfs-chunk-00); [ 105.384023] lock(&fs_devs->device_list_mutex); [ 105.396858] lock(btrfs-chunk-00); [ 105.409215] lock(&fs_devs->device_list_mutex); [ 105.421625] *** DEADLOCK *** [ 105.457447] 3 locks held by mount/670: [ 105.469302] #0: ffffa2270932e0e8 (&type->s_umount_key#54/1){+.+.}-{3:3}, at: alloc_super+0xdf/0x3c0 [ 105.494413] #1: ffffffffc0bdfdd0 (uuid_mutex){+.+.}-{3:3}, at: btrfs_read_chunk_tree+0x5c/0x7f0 [btrfs] [ 105.521072] #2: ffffa22750e32f20 (btrfs-chunk-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x2d/0x110 [btrfs] [ 105.549753] stack backtrace: [ 105.578187] CPU: 6 PID: 670 Comm: mount Tainted: G O 5.11.0-rc7-custom+ #55 [ 105.607477] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ArchLinux 1.14.0-1 04/01/2014 [ 105.638608] Call Trace: [ 105.653967] dump_stack+0x90/0xb8 [ 105.669419] print_circular_bug.cold+0x13d/0x142 [ 105.684814] check_noncircular+0xf2/0x110 [ 105.700322] ? check_path.constprop.0+0x26/0x40 [ 105.715821] __lock_acquire+0x11e0/0x1ea0 [ 105.731388] ? __this_cpu_preempt_check+0x13/0x20 [ 105.747097] ? lockdep_unlock+0x33/0xd0 [ 105.763012] lock_acquire+0xd8/0x3c0 [ 105.779043] ? clone_fs_devices+0x4f/0x160 [btrfs] [ 105.795343] __mutex_lock+0x8f/0x870 [ 105.811251] ? clone_fs_devices+0x4f/0x160 [btrfs] [ 105.827385] ? lockdep_init_map_waits+0x51/0x250 [ 105.843343] ? clone_fs_devices+0x4f/0x160 [btrfs] [ 105.859264] ? debug_mutex_init+0x36/0x50 [ 105.875378] ? __mutex_init+0x62/0x70 [ 105.891493] mutex_lock_nested+0x1b/0x20 [ 105.907847] clone_fs_devices+0x4f/0x160 [btrfs] [ 105.923756] ? btrfs_get_64+0x63/0x110 [btrfs] [ 105.939389] btrfs_read_chunk_tree+0x30e/0x7f0 [btrfs] [ 105.954580] open_ctree+0xb40/0x176a [btrfs] [ 105.969477] ? bdi_register_va+0x1b/0x20 [ 105.983674] ? super_setup_bdi_name+0x79/0xd0 [ 105.997611] btrfs_mount_root.cold+0x12/0xeb [btrfs] [ 106.011564] ? __kmalloc_track_caller+0x217/0x3b0 [ 106.026013] legacy_get_tree+0x34/0x60 [ 106.040045] vfs_get_tree+0x2d/0xc0 [ 106.053904] vfs_kern_mount.part.0+0x78/0xc0 [ 106.067296] vfs_kern_mount+0x13/0x20 [ 106.080125] btrfs_mount+0x11f/0x3c0 [btrfs] [ 106.093144] ? kfree+0x5ff/0x670 [ 106.106064] ? __kmalloc_track_caller+0x217/0x3b0 [ 106.119249] legacy_get_tree+0x34/0x60 [ 106.132216] vfs_get_tree+0x2d/0xc0 [ 106.145225] path_mount+0x48c/0xd30 [ 106.157899] __x64_sys_mount+0x108/0x140 [ 106.170654] do_syscall_64+0x38/0x50 [ 106.183208] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 106.196111] RIP: 0033:0x7fafa8869ebe [ 106.208994] Code: 48 8b 0d b5 0f 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 82 0f 0c 00 f7 d8 64 89 01 48 [ 106.250073] RSP: 002b:00007ffc04365b98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 [ 106.278571] RAX: ffffffffffffffda RBX: 00007fafa8994264 RCX: 00007fafa8869ebe [ 106.294048] RDX: 0000556726a02e00 RSI: 00005567269fc690 RDI: 00005567269fc670 [ 106.309646] RBP: 00005567269fc440 R08: 0000000000000000 R09: 00007fafa892ba60 [ 106.325336] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 106.340847] R13: 00005567269fc670 R14: 0000556726a02e00 R15: 00005567269fc440 [ 106.357929] BTRFS info (device sdb2): checking UUID tree