From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f78.google.com (mail-ot1-f78.google.com [209.85.210.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 935DD280317 for ; Tue, 30 Dec 2025 11:48:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767095308; cv=none; b=dgqremS7RQJtZxq9w00N2ur4602xZ5M2TL/VXvEnzwA3jW7gfFZxMM+IFze8LFZhB13wOIJ4EHDiwQr2W1kwd0XEeijSCMTn96f2ALTMUPm7+9gI7wRLgzOHRcaWgOEn+3VnbsO6jlyo/iZzqKfFYyawQKas22s0/ZmvYYcFUgE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767095308; c=relaxed/simple; bh=OAVqcnesl+4941j64kLR+lVilt41CCTBFJOiOR2ej4E=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=NkQCHuQWkWjEZgkUBYEmA+xjcPStMq0QnA81nQbFkbc2frVbIQFc9kY3M2crcOqPrLEBgH03ePy43cqK+tqfFTuSbZ+mHXCUQ8ENINvOePfup2KvFQpsW00dhmu88aDke5V9hG0qRvBRYTkRn/Rzg43xt//EW5HiBdcpxEs1e5M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.210.78 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-ot1-f78.google.com with SMTP id 46e09a7af769-7ce031c61ccso2254128a34.0 for ; Tue, 30 Dec 2025 03:48:26 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767095305; x=1767700105; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=ITeqqpPpxAut+DnobFXTlCH7OD3JuOzo/FU2J6DkIRQ=; b=Spu9I3VkDjG4aXMmcxUhx3k+nL54psnn+qijsnkjGeb9Vj5sfx+q2/kWQ9FjRP6Jfy MZUHfhxv0wmlqVMgE74h+hQoPkk01Pe9NrBcrBSlo5x2SXaQScHrC6w4FPZjwf0xIjbK Uis25JbI7dXAu3XSLs2N+UY6ghRl1Ebu8dzWt+AD8V5yAOxF/UVYopcDHge0vtKlja+4 sQuu16ZXpXSP5TDno5lujKirWYBjseHPHGVns7hBncx+31n4nEf3mp39v0ib+xMxDWQc UyKqR2lcFbLIVZPehi16TdGqQ70a1l8MqpTgRaTl13hJJ93l4zElVsDutjsyAzi2qvZO Lc1Q== X-Forwarded-Encrypted: i=1; AJvYcCXZr4EuTErPUti8tLTT8jkPdoPKsUQTi3fN63ozDQ0KxD+Jtl4ZH2tankD37WxXfdhMQYjqO6vl0k0k@vger.kernel.org X-Gm-Message-State: AOJu0YxzBsdCyja3mpwiiy9yEINJ2Imvok8U4oj/oHw64J/pwKVNQWpd ruf/rr8O8y/GQlE59XmX1yUfRruvMO2qvcqzwIQ9TBio80mjQ9ioWJiqlQBdAdNS9CXk3fI1F6L 7z0UjMwDKDbFGB5C+M+gSn3eNpMU8rqjoCozI5hzAuJ1H8wDAROzZLRPENNk= X-Google-Smtp-Source: AGHT+IFWQxjngUYb9BwtZhChKFw8+BbKcrnThTpFlpwtewvxEV71RBKs0z7uStnheTjDYiTWALrbKZLG1bDCfeS9O+s9aoDXmV9y Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:e15:b0:65b:8181:e191 with SMTP id 006d021491bc7-65cfe76f5bfmr12473791eaf.29.1767095305489; Tue, 30 Dec 2025 03:48:25 -0800 (PST) Date: Tue, 30 Dec 2025 03:48:25 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6953bc09.050a0220.329c0f.0592.GAE@google.com> Subject: [syzbot] [ext4?] possible deadlock in wait_transaction_locked (3) From: syzbot To: jack@suse.com, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 8640b74557fc Merge tag 'kbuild-fixes-6.19-1' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=142bbb92580000 kernel config: https://syzkaller.appspot.com/x/.config?x=a94030c847137a18 dashboard link: https://syzkaller.appspot.com/bug?extid=5d19358d7eb30ffb0cc5 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/b1a701044e2e/disk-8640b745.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/a8fd3c918355/vmlinux-8640b745.xz kernel image: https://storage.googleapis.com/syzbot-assets/bf28e4692fb2/bzImage-8640b745.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5d19358d7eb30ffb0cc5@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ kworker/u8:4/64 is trying to acquire lock: ffff88803375a950 (jbd2_handle){++++}-{0:0}, at: wait_transaction_locked+0x19d/0x270 fs/jbd2/transaction.c:151 but task is already holding lock: ffff888033758b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ffff888033758b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1820 [inline] ffff888033758b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1ca/0x350 fs/ext4/inode.c:3025 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sbi->s_writepages_rwsem){++++}-{0:0}: percpu_down_read_internal+0x48/0x1c0 include/linux/percpu-rwsem.h:53 percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ext4_writepages_down_read fs/ext4/ext4.h:1820 [inline] ext4_writepages+0x1ca/0x350 fs/ext4/inode.c:3025 do_writepages+0x32e/0x550 mm/page-writeback.c:2598 __writeback_single_inode+0x133/0x1240 fs/fs-writeback.c:1737 writeback_single_inode+0x493/0xc70 fs/fs-writeback.c:1858 write_inode_now+0x160/0x1d0 fs/fs-writeback.c:2924 iput_final fs/inode.c:1941 [inline] iput+0xa77/0x1030 fs/inode.c:2003 ext4_xattr_block_set+0x1fce/0x2ac0 fs/ext4/xattr.c:2203 ext4_xattr_move_to_block fs/ext4/xattr.c:2668 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2743 [inline] ext4_expand_extra_isize_ea+0x12da/0x1ea0 fs/ext4/xattr.c:2831 __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6349 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6392 [inline] __ext4_mark_inode_dirty+0x45c/0x6e0 fs/ext4/inode.c:6470 ext4_evict_inode+0x79c/0xe60 fs/ext4/inode.c:253 evict+0x5f4/0xae0 fs/inode.c:837 ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5658 [inline] ext4_fill_super+0x58a1/0x6160 fs/ext4/super.c:5777 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 vfs_get_tree+0x92/0x2a0 fs/super.c:1751 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3712 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&ei->xattr_sem){++++}-{4:4}: down_read+0x47/0x2e0 kernel/locking/rwsem.c:1537 ext4_setattr+0x855/0x1bc0 fs/ext4/inode.c:5865 notify_change+0xc1a/0xf40 fs/attr.c:546 chown_common+0x40c/0x5b0 fs/open.c:788 do_fchownat+0x161/0x270 fs/open.c:819 __do_sys_chown fs/open.c:839 [inline] __se_sys_chown fs/open.c:837 [inline] __x64_sys_chown+0x82/0xa0 fs/open.c:837 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (jbd2_handle){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 wait_transaction_locked+0x1b6/0x270 fs/jbd2/transaction.c:151 add_transaction_credits fs/jbd2/transaction.c:222 [inline] start_this_handle+0x77d/0x21c0 fs/jbd2/transaction.c:403 jbd2__journal_start+0x2c1/0x5b0 fs/jbd2/transaction.c:501 __ext4_journal_start_sb+0x203/0x580 fs/ext4/ext4_jbd2.c:114 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline] ext4_do_writepages+0xf3e/0x4500 fs/ext4/inode.c:2914 ext4_writepages+0x203/0x350 fs/ext4/inode.c:3026 do_writepages+0x32e/0x550 mm/page-writeback.c:2598 __writeback_single_inode+0x133/0x1240 fs/fs-writeback.c:1737 writeback_sb_inodes+0x93a/0x1870 fs/fs-writeback.c:2030 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2107 wb_writeback+0x43f/0xaa0 fs/fs-writeback.c:2218 wb_check_old_data_flush fs/fs-writeback.c:2322 [inline] wb_do_writeback fs/fs-writeback.c:2375 [inline] wb_workfn+0xad2/0xed0 fs/fs-writeback.c:2403 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 other info that might help us debug this: Chain exists of: jbd2_handle --> &ei->xattr_sem --> &sbi->s_writepages_rwsem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); lock(&sbi->s_writepages_rwsem); lock(jbd2_handle); *** DEADLOCK *** 4 locks held by kworker/u8:4/64: #0: ffff88801def2948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801def2948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc9000213fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000213fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffff8880336760e0 (&type->s_umount_key#31){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff888033758b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline] #3: ffff888033758b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1820 [inline] #3: ffff888033758b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1ca/0x350 fs/ext4/inode.c:3025 stack backtrace: CPU: 1 UID: 0 PID: 64 Comm: kworker/u8:4 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 wait_transaction_locked+0x1b6/0x270 fs/jbd2/transaction.c:151 add_transaction_credits fs/jbd2/transaction.c:222 [inline] start_this_handle+0x77d/0x21c0 fs/jbd2/transaction.c:403 jbd2__journal_start+0x2c1/0x5b0 fs/jbd2/transaction.c:501 __ext4_journal_start_sb+0x203/0x580 fs/ext4/ext4_jbd2.c:114 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline] ext4_do_writepages+0xf3e/0x4500 fs/ext4/inode.c:2914 ext4_writepages+0x203/0x350 fs/ext4/inode.c:3026 do_writepages+0x32e/0x550 mm/page-writeback.c:2598 __writeback_single_inode+0x133/0x1240 fs/fs-writeback.c:1737 writeback_sb_inodes+0x93a/0x1870 fs/fs-writeback.c:2030 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2107 wb_writeback+0x43f/0xaa0 fs/fs-writeback.c:2218 wb_check_old_data_flush fs/fs-writeback.c:2322 [inline] wb_do_writeback fs/fs-writeback.c:2375 [inline] wb_workfn+0xad2/0xed0 fs/fs-writeback.c:2403 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup