BTRFS info (device loop3): clearing free space tree BTRFS info (device loop3): clearing compat-ro feature flag for FREE_SPACE_TREE (0x1) BTRFS info (device loop3): clearing compat-ro feature flag for FREE_SPACE_TREE_VALID (0x2) ====================================================== WARNING: possible circular locking dependency detected 5.15.182-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.18/5225 is trying to acquire lock: ffff888056095e60 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:797 [inline] ffff888056095e60 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1679 but task is already holding lock: ffff8880598740e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_free_stale_devices+0x186/0xa60 fs/btrfs/volumes.c:603 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 btrfs_run_dev_stats+0xdf/0xdf0 fs/btrfs/volumes.c:7985 commit_cowonly_roots+0x17e/0x9c0 fs/btrfs/transaction.c:1292 btrfs_commit_transaction+0x1229/0x3440 fs/btrfs/transaction.c:2394 btrfs_clear_free_space_tree+0x786/0xbf0 fs/btrfs/free-space-tree.c:1264 btrfs_start_pre_rw_mount+0x287/0x630 fs/btrfs/disk-io.c:3079 open_ctree+0x2878/0x3250 fs/btrfs/disk-io.c:3634 btrfs_fill_super+0x1c2/0x2e0 fs/btrfs/super.c:1387 btrfs_mount_root+0x857/0x8c0 fs/btrfs/super.c:1751 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611 vfs_get_tree+0x88/0x270 fs/super.c:1530 fc_mount fs/namespace.c:1000 [inline] vfs_kern_mount+0xba/0x150 fs/namespace.c:1030 btrfs_mount+0x2d7/0xa50 fs/btrfs/super.c:1811 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611 vfs_get_tree+0x88/0x270 fs/super.c:1530 do_new_mount+0x24a/0xa40 fs/namespace.c:3013 do_mount fs/namespace.c:3356 [inline] __do_sys_mount fs/namespace.c:3564 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3541 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #2 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __lock_release kernel/locking/lockdep.c:5339 [inline] lock_release+0x31a/0x870 kernel/locking/lockdep.c:5643 __mutex_unlock_slowpath+0xb3/0x6a0 kernel/locking/mutex.c:851 btrfs_commit_transaction+0x1c11/0x3440 fs/btrfs/transaction.c:2441 btrfs_clear_free_space_tree+0x786/0xbf0 fs/btrfs/free-space-tree.c:1264 btrfs_start_pre_rw_mount+0x287/0x630 fs/btrfs/disk-io.c:3079 open_ctree+0x2878/0x3250 fs/btrfs/disk-io.c:3634 btrfs_fill_super+0x1c2/0x2e0 fs/btrfs/super.c:1387 btrfs_mount_root+0x857/0x8c0 fs/btrfs/super.c:1751 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611 vfs_get_tree+0x88/0x270 fs/super.c:1530 fc_mount fs/namespace.c:1000 [inline] vfs_kern_mount+0xba/0x150 fs/namespace.c:1030 btrfs_mount+0x2d7/0xa50 fs/btrfs/super.c:1811 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611 vfs_get_tree+0x88/0x270 fs/super.c:1530 do_new_mount+0x24a/0xa40 fs/namespace.c:3013 do_mount fs/namespace.c:3356 [inline] __do_sys_mount fs/namespace.c:3564 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3541 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (sb_internal#2){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1811 [inline] sb_start_intwrite include/linux/fs.h:1928 [inline] start_transaction+0x5bc/0x1130 fs/btrfs/transaction.c:680 btrfs_dirty_inode+0xc5/0x1c0 fs/btrfs/inode.c:6436 btrfs_setattr+0x23e/0xe60 fs/btrfs/inode.c:5495 notify_change+0xbcd/0xee0 fs/attr.c:505 chown_common+0x483/0x610 fs/open.c:680 do_fchownat+0x164/0x270 fs/open.c:711 __do_sys_lchown fs/open.c:736 [inline] __se_sys_lchown fs/open.c:734 [inline] __x64_sys_lchown+0x81/0x90 fs/open.c:734 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&type->i_mutex_dir_key#8){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 inode_lock_shared include/linux/fs.h:797 [inline] lookup_slow+0x46/0x70 fs/namei.c:1679 walk_component+0x319/0x460 fs/namei.c:1976 lookup_last fs/namei.c:2431 [inline] path_lookupat+0x169/0x440 fs/namei.c:2455 filename_lookup+0x1e2/0x4f0 fs/namei.c:2484 kern_path+0x37/0x190 fs/namei.c:2582 lookup_bdev+0xbd/0x270 block/bdev.c:982 device_matched fs/btrfs/volumes.c:568 [inline] btrfs_free_stale_devices+0x6db/0xa60 fs/btrfs/volumes.c:608 btrfs_forget_devices+0x52/0x80 fs/btrfs/volumes.c:1431 btrfs_control_ioctl+0x104/0x220 fs/btrfs/super.c:2450 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: &type->i_mutex_dir_key#8 --> &fs_info->tree_log_mutex --> &fs_devs->device_list_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_devs->device_list_mutex); lock(&fs_info->tree_log_mutex); lock(&fs_devs->device_list_mutex); lock(&type->i_mutex_dir_key#8); *** DEADLOCK *** 2 locks held by syz.3.18/5225: #0: ffffffff8c6066a8 (uuid_mutex){+.+.}-{3:3}, at: btrfs_forget_devices+0x1a/0x80 fs/btrfs/volumes.c:1430 #1: ffff8880598740e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_free_stale_devices+0x186/0xa60 fs/btrfs/volumes.c:603 stack backtrace: CPU: 0 PID: 5225 Comm: syz.3.18 Not tainted 5.15.182-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 inode_lock_shared include/linux/fs.h:797 [inline] lookup_slow+0x46/0x70 fs/namei.c:1679 walk_component+0x319/0x460 fs/namei.c:1976 lookup_last fs/namei.c:2431 [inline] path_lookupat+0x169/0x440 fs/namei.c:2455 filename_lookup+0x1e2/0x4f0 fs/namei.c:2484 kern_path+0x37/0x190 fs/namei.c:2582 lookup_bdev+0xbd/0x270 block/bdev.c:982 device_matched fs/btrfs/volumes.c:568 [inline] btrfs_free_stale_devices+0x6db/0xa60 fs/btrfs/volumes.c:608 btrfs_forget_devices+0x52/0x80 fs/btrfs/volumes.c:1431 btrfs_control_ioctl+0x104/0x220 fs/btrfs/super.c:2450 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f5db0ec0ed9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5db013f058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5db1086fa0 RCX: 00007f5db0ec0ed9 RDX: 0000000020000100 RSI: 0000000050009405 RDI: 0000000000000004 RBP: 00007f5db0f34cc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f5db1086fa0 R15: 00007ffc50b47e28