loop0: detected capacity change from 0 to 32768 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.119/6686 is trying to acquire lock: ffff8880644c8c38 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline] ffff8880644c8c38 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1932 but task is already holding lock: ffff888037430cc8 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: device_list_add+0x487/0x2280 fs/btrfs/volumes.c:842 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (&fs_devs->device_list_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 btrfs_run_dev_stats+0xfa/0x10f0 fs/btrfs/volumes.c:8081 commit_cowonly_roots+0x1b8/0x860 fs/btrfs/transaction.c:1359 btrfs_commit_transaction+0x1057/0x31a0 fs/btrfs/transaction.c:2502 sync_filesystem+0x1ce/0x250 fs/sync.c:66 btrfs_reconfigure+0x317/0x2180 fs/btrfs/super.c:1518 reconfigure_super+0x227/0x8a0 fs/super.c:1080 do_remount fs/namespace.c:3391 [inline] path_mount+0xdc5/0x10e0 fs/namespace.c:4151 do_mount fs/namespace.c:4172 [inline] __do_sys_mount fs/namespace.c:4361 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4338 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #5 (&fs_info->reloc_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 btrfs_record_root_in_trans+0x14f/0x180 fs/btrfs/transaction.c:505 start_transaction+0x3a6/0x1650 fs/btrfs/transaction.c:782 btrfs_rename fs/btrfs/inode.c:8685 [inline] btrfs_rename2+0x1676/0x40d0 fs/btrfs/inode.c:8854 vfs_rename+0xa96/0xeb0 fs/namei.c:6032 filename_renameat2+0x539/0x9c0 fs/namei.c:6150 __do_sys_renameat2 fs/namei.c:6179 [inline] __se_sys_renameat2+0x5a/0x2c0 fs/namei.c:6174 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x1a4/0xc90 fs/btrfs/transaction.c:323 start_transaction+0x6b9/0x1650 fs/btrfs/transaction.c:708 btrfs_rename fs/btrfs/inode.c:8685 [inline] btrfs_rename2+0x1676/0x40d0 fs/btrfs/inode.c:8854 vfs_rename+0xa96/0xeb0 fs/namei.c:6032 filename_renameat2+0x539/0x9c0 fs/namei.c:6150 __do_sys_renameat2 fs/namei.c:6179 [inline] __se_sys_renameat2+0x5a/0x2c0 fs/namei.c:6174 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (btrfs_trans_num_writers){++++}-{0:0}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x199/0x3d0 kernel/locking/lockdep.c:5889 percpu_up_read include/linux/percpu-rwsem.h:112 [inline] __sb_end_write include/linux/fs/super.h:14 [inline] sb_end_intwrite+0x26/0x1c0 include/linux/fs/super.h:101 __btrfs_end_transaction+0x248/0x640 fs/btrfs/transaction.c:1085 btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6457 file_update_time_flags+0x2d5/0x4b0 fs/inode.c:2426 btrfs_page_mkwrite+0x5df/0x1b10 fs/btrfs/file.c:1914 do_page_mkwrite+0x150/0x310 mm/memory.c:3589 wp_page_shared mm/memory.c:3990 [inline] do_wp_page+0x203b/0x49d0 mm/memory.c:4209 handle_pte_fault mm/memory.c:6333 [inline] __handle_mm_fault mm/memory.c:6455 [inline] handle_mm_fault+0x9f5/0x13c0 mm/memory.c:6624 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 -> #2 (sb_pagefaults#4){.+.+}-{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/super.h:19 [inline] sb_start_pagefault include/linux/fs/super.h:159 [inline] btrfs_page_mkwrite+0x329/0x1b10 fs/btrfs/file.c:1873 do_page_mkwrite+0x150/0x310 mm/memory.c:3589 do_shared_fault mm/memory.c:5875 [inline] do_fault mm/memory.c:5937 [inline] do_pte_missing+0x711/0x29e0 mm/memory.c:4477 handle_pte_fault mm/memory.c:6317 [inline] __handle_mm_fault mm/memory.c:6455 [inline] handle_mm_fault+0xd0a/0x13c0 mm/memory.c:6624 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 -> #1 (&mm->mmap_lock){++++}-{4:4}: down_read_killable+0xa4/0x220 kernel/locking/rwsem.c:1560 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:601 get_mmap_lock_carefully mm/mmap_lock.c:450 [inline] lock_mm_and_find_vma+0x2d7/0x340 mm/mmap_lock.c:501 do_user_addr_fault+0x330/0x1340 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 filldir64+0x2c0/0x670 fs/readdir.c:-1 dir_emit include/linux/fs.h:3566 [inline] offset_dir_emit fs/libfs.c:500 [inline] offset_iterate_dir fs/libfs.c:516 [inline] offset_readdir+0x3fc/0x530 fs/libfs.c:565 iterate_dir+0x3a5/0x580 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:412 [inline] __se_sys_getdents64+0xf1/0x280 fs/readdir.c:397 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&type->i_mutex_dir_key#5){++++}-{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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 down_read+0x97/0x200 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:1043 [inline] lookup_slow+0x46/0x70 fs/namei.c:1932 walk_component fs/namei.c:2279 [inline] lookup_last fs/namei.c:2786 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2810 filename_lookup+0x256/0x5d0 fs/namei.c:2839 kern_path+0x3d/0x150 fs/namei.c:3046 is_same_device fs/btrfs/volumes.c:763 [inline] device_list_add+0xfd1/0x2280 fs/btrfs/volumes.c:897 btrfs_scan_one_device+0x3ef/0x680 fs/btrfs/volumes.c:1498 btrfs_get_tree_super fs/btrfs/super.c:1858 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline] btrfs_get_tree+0x4ab/0x1930 fs/btrfs/super.c:2121 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3763 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3839 do_mount fs/namespace.c:4172 [inline] __do_sys_mount fs/namespace.c:4361 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4338 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &type->i_mutex_dir_key#5 --> &fs_info->reloc_mutex --> &fs_devs->device_list_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_devs->device_list_mutex); lock(&fs_info->reloc_mutex); lock(&fs_devs->device_list_mutex); rlock(&type->i_mutex_dir_key#5); *** DEADLOCK *** 2 locks held by syz.0.119/6686: #0: ffffffff8e3d9c78 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree_super fs/btrfs/super.c:1852 [inline] #0: ffffffff8e3d9c78 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline] #0: ffffffff8e3d9c78 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree+0x47c/0x1930 fs/btrfs/super.c:2121 #1: ffff888037430cc8 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: device_list_add+0x487/0x2280 fs/btrfs/volumes.c:842 stack backtrace: CPU: 0 UID: 0 PID: 6686 Comm: syz.0.119 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 down_read+0x97/0x200 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:1043 [inline] lookup_slow+0x46/0x70 fs/namei.c:1932 walk_component fs/namei.c:2279 [inline] lookup_last fs/namei.c:2786 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2810 filename_lookup+0x256/0x5d0 fs/namei.c:2839 kern_path+0x3d/0x150 fs/namei.c:3046 is_same_device fs/btrfs/volumes.c:763 [inline] device_list_add+0xfd1/0x2280 fs/btrfs/volumes.c:897 btrfs_scan_one_device+0x3ef/0x680 fs/btrfs/volumes.c:1498 btrfs_get_tree_super fs/btrfs/super.c:1858 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline] btrfs_get_tree+0x4ab/0x1930 fs/btrfs/super.c:2121 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3763 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3839 do_mount fs/namespace.c:4172 [inline] __do_sys_mount fs/namespace.c:4361 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4338 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f910f3dda8a Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f910d62de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f910d62dee0 RCX: 00007f910f3dda8a RDX: 0000200000000000 RSI: 00002000000015c0 RDI: 00007f910d62dea0 RBP: 0000200000000000 R08: 00007f910d62dee0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000015c0 R13: 00007f910d62dea0 R14: 000000000000559e R15: 0000200000000040 BTRFS info (device loop0): first mount of filesystem 395ef67a-297e-477c-816d-cd80a5b93e5d BTRFS info (device loop0): using sha256 checksum algorithm BTRFS error (device loop0): open_ctree failed: -4