From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f207.google.com (mail-oi1-f207.google.com [209.85.167.207]) (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 DEB2E2C0F9C for ; Wed, 3 Dec 2025 08:21:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764750087; cv=none; b=nDqfQpZTa6huPlABAwbiAEytK/E5H0Tvc3qKT7GlErFMpHp0X3i++EFugwKJ52clORx0yj4rZnpW63D0z2TGXUQOnvRy3cFiEHmHiv6YOQr7NVx3NfEbDr83nxYvAscEKF5XB7O5bvYcFKxFPfug0p8QzdktvyUJzUQRy3aHdgI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764750087; c=relaxed/simple; bh=duGnPjeykp+Kojhvw933qqFROtCcZWLDWXYZ7OOs4yc=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=DPnIsL0efvmkO+C3/A4iWT54lp2a44Aup/q/ZyDT9exs5ebfMR6jnbyLDXf67Y4nlSwxIAnPiwZ4B3lRT9Oa3g/laF2wWBp0oxvYDmdcWsjUNrgzFbeC4LyniUKJX8L0DBXQMpEhdGpltm9piC/yuhlPzvmG61lvLmudb69zPwU= 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=209.85.167.207 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-oi1-f207.google.com with SMTP id 5614622812f47-450fd003480so7571302b6e.2 for ; Wed, 03 Dec 2025 00:21:25 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764750085; x=1765354885; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=l4XaMB4ZEoj+wWuKfCMQMoDgXHSQREgdhwGzG7wgxco=; b=oUll2FzlWAyVdtjZgN25ApKPxIAZiNR0DGDf6UC7QgX6FnC96ybLYlVDTlGbp0GJxx lwsgr12pex792zaSzyQKzlxIAjF8qgWpfMj0uXH7eXltFRfbNyfW7lfzJvxX7BgCPe1t KafvNIZgAmyVN1lTKFEZyqrAcu9APYVbjNR9iswSk8w3TA5lrCm26N6U9qsoXrDqsJYY U/8FYW4/k28bR9pUUZ//z/Ehj6PLJVCiGV1K9AG/fzKFTK1XM4Y/FKGwv4oZSBMsQnCT 0jZufA22OLyCmSmRdFDYnjOGeB/Yy+AzLFcsdrl/XQ0Ln6orIjfGWqW8MRiKAzNl0N5I 15FQ== X-Forwarded-Encrypted: i=1; AJvYcCU3GVTUv3jMSRirKqsjylq/sIzgPbAdqE4DjBdDMq6O2s5VAU0umczLHl52pRtotECgtwTr3FGG4lI7Ow==@vger.kernel.org X-Gm-Message-State: AOJu0YxNeBq3labaWG23RbofjQ4Ms9ipHEi7I2UTIJG66g2OmDZ5Bmq+ 1E1UFE5rkjRcZ50ZJxCetGmjSXfB8a3S65hdSsr9Acb5rKuct0erUf0Ze5dC9HRBVDRViS44HpA bG/GDiqvMKpP7S9aanXTDNbmEdb2ur2P9/zCZMJNsi3n3WznS8UDHM8R9B9g= X-Google-Smtp-Source: AGHT+IGMgyC2rk0Pq+pW67CVX42LUvfjPYPtEBloq+xztlBG3mu47MdwXTKtddu5LQGoutmVy0MIUMmv7iP1EaVQz5A8EU9cKi2K Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:300e:b0:450:d7fb:85c2 with SMTP id 5614622812f47-4536e3d9bfdmr721420b6e.19.1764750084903; Wed, 03 Dec 2025 00:21:24 -0800 (PST) Date: Wed, 03 Dec 2025 00:21:24 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <692ff304.a70a0220.d98e3.01b4.GAE@google.com> Subject: [syzbot] [btrfs?] possible deadlock in btrfs_page_mkwrite From: syzbot To: clm@fb.com, dsterba@suse.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 05c93f3395ed Merge branch 'for-next/core' into for-kernelci git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci console output: https://syzkaller.appspot.com/x/log.txt?x=16cfa112580000 kernel config: https://syzkaller.appspot.com/x/.config?x=3b5338ad1e59a06c dashboard link: https://syzkaller.appspot.com/bug?extid=8ff80a43de91ba2d80fc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 userspace arch: arm64 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/6b5c913e373c/disk-05c93f33.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/15e75f1266ef/vmlinux-05c93f33.xz kernel image: https://storage.googleapis.com/syzbot-assets/dd930129c578/Image-05c93f33.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+8ff80a43de91ba2d80fc@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.810/10993 is trying to acquire lock: ffff0000f98b59b8 (&ei->i_mmap_lock){++++}-{4:4}, at: btrfs_page_mkwrite+0x5a4/0x1714 fs/btrfs/file.c:1919 but task is already holding lock: ffff0000cadb8518 (sb_pagefaults#7){.+.+}-{0:0}, at: do_page_mkwrite+0x138/0x2b8 mm/memory.c:3489 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (sb_pagefaults#7){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs.h:1916 [inline] sb_start_pagefault include/linux/fs.h:2081 [inline] btrfs_page_mkwrite+0x284/0x1714 fs/btrfs/file.c:1874 do_page_mkwrite+0x138/0x2b8 mm/memory.c:3489 do_shared_fault mm/memory.c:5792 [inline] do_fault mm/memory.c:5854 [inline] do_pte_missing mm/memory.c:4362 [inline] handle_pte_fault mm/memory.c:6234 [inline] __handle_mm_fault+0x178c/0x4798 mm/memory.c:6366 handle_mm_fault+0x274/0x7fc mm/memory.c:6535 do_page_fault+0x57c/0x13cc arch/arm64/mm/fault.c:700 do_translation_fault+0xc4/0x114 arch/arm64/mm/fault.c:793 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:933 el0_da+0x64/0x230 arch/arm64/kernel/entry-common.c:540 el0t_64_sync_handler+0x90/0x12c arch/arm64/kernel/entry-common.c:746 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #5 (&mm->mmap_lock){++++}-{4:4}: down_read_killable+0x60/0x32c kernel/locking/rwsem.c:1560 mmap_read_lock_killable+0x28/0x8c include/linux/mmap_lock.h:377 get_mmap_lock_carefully mm/mmap_lock.c:377 [inline] lock_mm_and_find_vma+0x2a4/0x2d8 mm/mmap_lock.c:428 do_page_fault+0x50c/0x13cc arch/arm64/mm/fault.c:678 do_translation_fault+0xc4/0x114 arch/arm64/mm/fault.c:793 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:933 el1_abort+0x40/0x64 arch/arm64/kernel/entry-common.c:303 el1h_64_sync_handler+0x50/0xfc arch/arm64/kernel/entry-common.c:437 el1h_64_sync+0x6c/0x70 arch/arm64/kernel/entry.S:591 __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:169 [inline] filldir64+0x314/0x6bc fs/readdir.c:381 dir_emit include/linux/fs.h:3988 [inline] kernfs_fop_readdir+0x498/0x79c fs/kernfs/dir.c:1910 iterate_dir+0x2dc/0x478 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:410 [inline] __se_sys_getdents64 fs/readdir.c:396 [inline] __arm64_sys_getdents64+0x110/0x2fc fs/readdir.c:396 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #4 (&root->kernfs_rwsem){++++}-{4:4}: down_write+0x50/0xc0 kernel/locking/rwsem.c:1590 kernfs_add_one+0x48/0x60c fs/kernfs/dir.c:791 kernfs_create_dir_ns+0xd4/0x12c fs/kernfs/dir.c:1093 sysfs_create_dir_ns+0x114/0x24c fs/sysfs/dir.c:59 create_dir lib/kobject.c:73 [inline] kobject_add_internal+0x5a8/0xb20 lib/kobject.c:240 kobject_add_varg lib/kobject.c:374 [inline] kobject_init_and_add+0x118/0x17c lib/kobject.c:457 btrfs_sysfs_add_qgroups+0x110/0x268 fs/btrfs/sysfs.c:2645 btrfs_quota_enable+0x210/0x2438 fs/btrfs/qgroup.c:1022 btrfs_ioctl_quota_ctl+0x178/0x1bc fs/btrfs/ioctl.c:3667 btrfs_ioctl+0x86c/0xc3c fs/btrfs/ioctl.c:5333 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #3 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 btrfs_quota_enable+0x24c/0x2438 fs/btrfs/qgroup.c:1051 btrfs_ioctl_quota_ctl+0x178/0x1bc fs/btrfs/ioctl.c:3667 btrfs_ioctl+0x86c/0xc3c fs/btrfs/ioctl.c:5333 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #2 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x190/0xb5c fs/btrfs/transaction.c:321 start_transaction+0x778/0x155c fs/btrfs/transaction.c:705 btrfs_start_transaction+0x34/0x44 fs/btrfs/transaction.c:816 btrfs_rebuild_free_space_tree+0xac/0x6c0 fs/btrfs/free-space-tree.c:1340 btrfs_start_pre_rw_mount+0xed8/0x1728 fs/btrfs/disk-io.c:3062 open_ctree+0x24cc/0x358c fs/btrfs/disk-io.c:3619 btrfs_fill_super fs/btrfs/super.c:987 [inline] btrfs_get_tree_super fs/btrfs/super.c:1951 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2094 [inline] btrfs_get_tree+0xd94/0x15dc fs/btrfs/super.c:2128 vfs_get_tree+0x90/0x28c fs/super.c:1758 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3642 [inline] do_new_mount+0x284/0x944 fs/namespace.c:3718 path_mount+0x5b4/0xdfc fs/namespace.c:4028 do_mount fs/namespace.c:4041 [inline] __do_sys_mount fs/namespace.c:4229 [inline] __se_sys_mount fs/namespace.c:4206 [inline] __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4206 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #1 (btrfs_trans_num_writers){++++}-{0:0}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x198/0x39c kernel/locking/lockdep.c:5889 percpu_up_read include/linux/percpu-rwsem.h:112 [inline] __sb_end_write include/linux/fs.h:1911 [inline] sb_end_intwrite+0x3c/0x348 include/linux/fs.h:2028 __btrfs_end_transaction+0x1f4/0x5f4 fs/btrfs/transaction.c:1076 btrfs_end_transaction+0x24/0x34 fs/btrfs/transaction.c:1110 __btrfs_prealloc_file_range+0x77c/0xb28 fs/btrfs/inode.c:9145 btrfs_prealloc_file_range+0x60/0x7c fs/btrfs/inode.c:9159 btrfs_zero_range+0x928/0xb7c fs/btrfs/file.c:3070 btrfs_fallocate+0x8ec/0x1734 fs/btrfs/file.c:3181 vfs_fallocate+0x52c/0x668 fs/open.c:342 ksys_fallocate fs/open.c:366 [inline] __do_sys_fallocate fs/open.c:371 [inline] __se_sys_fallocate fs/open.c:369 [inline] __arm64_sys_fallocate+0xbc/0x10c fs/open.c:369 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #0 (&ei->i_mmap_lock){++++}-{4:4}: 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+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 down_read+0x58/0x2f8 kernel/locking/rwsem.c:1537 btrfs_page_mkwrite+0x5a4/0x1714 fs/btrfs/file.c:1919 do_page_mkwrite+0x138/0x2b8 mm/memory.c:3489 do_shared_fault mm/memory.c:5792 [inline] do_fault mm/memory.c:5854 [inline] do_pte_missing mm/memory.c:4362 [inline] handle_pte_fault mm/memory.c:6234 [inline] __handle_mm_fault+0x178c/0x4798 mm/memory.c:6366 handle_mm_fault+0x274/0x7fc mm/memory.c:6535 do_page_fault+0x57c/0x13cc arch/arm64/mm/fault.c:700 do_translation_fault+0xc4/0x114 arch/arm64/mm/fault.c:793 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:933 el0_da+0x64/0x230 arch/arm64/kernel/entry-common.c:540 el0t_64_sync_handler+0x90/0x12c arch/arm64/kernel/entry-common.c:746 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 other info that might help us debug this: Chain exists of: &ei->i_mmap_lock --> &mm->mmap_lock --> sb_pagefaults#7 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_pagefaults#7); lock(&mm->mmap_lock); lock(sb_pagefaults#7); rlock(&ei->i_mmap_lock); *** DEADLOCK *** 2 locks held by syz.1.810/10993: #0: ffff0000cf866790 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:387 [inline] #0: ffff0000cf866790 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:368 [inline] #0: ffff0000cf866790 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x38/0x2d8 mm/mmap_lock.c:428 #1: ffff0000cadb8518 (sb_pagefaults#7){.+.+}-{0:0}, at: do_page_mkwrite+0x138/0x2b8 mm/memory.c:3489 stack backtrace: CPU: 0 UID: 0 PID: 10993 Comm: syz.1.810 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043 check_noncircular+0x154/0x174 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+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 down_read+0x58/0x2f8 kernel/locking/rwsem.c:1537 btrfs_page_mkwrite+0x5a4/0x1714 fs/btrfs/file.c:1919 do_page_mkwrite+0x138/0x2b8 mm/memory.c:3489 do_shared_fault mm/memory.c:5792 [inline] do_fault mm/memory.c:5854 [inline] do_pte_missing mm/memory.c:4362 [inline] handle_pte_fault mm/memory.c:6234 [inline] __handle_mm_fault+0x178c/0x4798 mm/memory.c:6366 handle_mm_fault+0x274/0x7fc mm/memory.c:6535 do_page_fault+0x57c/0x13cc arch/arm64/mm/fault.c:700 do_translation_fault+0xc4/0x114 arch/arm64/mm/fault.c:793 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:933 el0_da+0x64/0x230 arch/arm64/kernel/entry-common.c:540 el0t_64_sync_handler+0x90/0x12c arch/arm64/kernel/entry-common.c:746 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 --- 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