loop1: detected capacity change from 0 to 32768 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.1.5150/1977 is trying to acquire lock: ffff8880556d32c0 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1044 [inline] ffff8880556d32c0 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1931 but task is already holding lock: ffff8880837258d0 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: device_list_add+0x487/0x2280 fs/btrfs/volumes.c:843 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&fs_devs->device_list_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x19e/0x1420 kernel/locking/mutex.c:794 insert_dev_extents fs/btrfs/block-group.c:2876 [inline] btrfs_create_pending_block_groups+0x77b/0x1b40 fs/btrfs/block-group.c:2927 __btrfs_end_transaction+0x140/0x640 fs/btrfs/transaction.c:1091 btrfs_inc_block_group_ro+0x647/0x7c0 fs/btrfs/block-group.c:3219 btrfs_relocate_block_group+0x3bb/0xc40 fs/btrfs/relocation.c:5359 btrfs_relocate_chunk+0x115/0x820 fs/btrfs/volumes.c:3598 __btrfs_balance+0x1db0/0x2ae0 fs/btrfs/volumes.c:4509 btrfs_balance+0xaf3/0x11b0 fs/btrfs/volumes.c:4896 btrfs_ioctl_balance+0x3d3/0x610 fs/btrfs/ioctl.c:3452 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x1a4/0xd60 fs/btrfs/transaction.c:324 start_transaction+0xb07/0x1790 fs/btrfs/transaction.c:719 btrfs_create_common+0x15c/0x310 fs/btrfs/inode.c:6975 lookup_open fs/namei.c:4511 [inline] open_last_lookups fs/namei.c:4611 [inline] path_openat+0x1395/0x3860 fs/namei.c:4855 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_open fs/open.c:1378 [inline] __se_sys_open fs/open.c:1374 [inline] __x64_sys_open+0x11e/0x150 fs/open.c:1374 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (btrfs_trans_num_writers){++++}-{0:0}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x199/0x3c0 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:1096 btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6451 touch_atime+0x2f8/0x6b0 fs/inode.c:2265 file_accessed include/linux/fs.h:2271 [inline] btrfs_file_mmap_prepare+0x172/0x1f0 fs/btrfs/file.c:2051 vfs_mmap_prepare include/linux/fs.h:2083 [inline] call_mmap_prepare mm/vma.c:2672 [inline] __mmap_region mm/vma.c:2755 [inline] mmap_region+0xe96/0x2280 mm/vma.c:2856 do_mmap+0xc39/0x10c0 mm/mmap.c:560 vm_mmap_pgoff+0x2c9/0x4f0 mm/util.c:581 ksys_mmap_pgoff+0x51e/0x760 mm/mmap.c:606 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&mm->mmap_lock){++++}-{4:4}: down_read_killable+0x50/0x340 kernel/locking/rwsem.c:1593 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 stac arch/x86/include/asm/smap.h:-1 [inline] filldir+0x299/0x650 fs/readdir.c:286 dir_emit_dot include/linux/fs.h:3576 [inline] dir_emit_dots include/linux/fs.h:3587 [inline] offset_readdir+0x1aa/0x530 fs/libfs.c:561 iterate_dir+0x399/0x570 fs/readdir.c:110 __do_sys_getdents fs/readdir.c:319 [inline] __se_sys_getdents+0xf1/0x270 fs/readdir.c:304 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/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+0x106/0x350 kernel/locking/lockdep.c:5868 down_read+0x47/0x2e0 kernel/locking/rwsem.c:1568 inode_lock_shared include/linux/fs.h:1044 [inline] lookup_slow+0x46/0x70 fs/namei.c:1931 walk_component fs/namei.c:2278 [inline] lookup_last fs/namei.c:2785 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2809 filename_lookup+0x256/0x5d0 fs/namei.c:2838 kern_path+0x3d/0x150 fs/namei.c:3044 is_same_device fs/btrfs/volumes.c:764 [inline] device_list_add+0xfd1/0x2280 fs/btrfs/volumes.c:898 btrfs_scan_one_device+0x3ef/0x680 fs/btrfs/volumes.c:1499 btrfs_get_tree_super fs/btrfs/super.c:1858 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline] btrfs_get_tree+0x4ab/0x1910 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:3758 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3834 do_mount fs/namespace.c:4167 [inline] __do_sys_mount fs/namespace.c:4399 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4376 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/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 --> btrfs_trans_num_extwriters --> &fs_devs->device_list_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_devs->device_list_mutex); lock(btrfs_trans_num_extwriters); lock(&fs_devs->device_list_mutex); rlock(&type->i_mutex_dir_key#5); *** DEADLOCK *** 2 locks held by syz.1.5150/1977: #0: ffffffff8ef7f800 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree_super fs/btrfs/super.c:1852 [inline] #0: ffffffff8ef7f800 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline] #0: ffffffff8ef7f800 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree+0x47c/0x1910 fs/btrfs/super.c:2121 #1: ffff8880837258d0 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: device_list_add+0x487/0x2280 fs/btrfs/volumes.c:843 stack backtrace: CPU: 1 UID: 0 PID: 1977 Comm: syz.1.5150 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP 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+0x106/0x350 kernel/locking/lockdep.c:5868 down_read+0x47/0x2e0 kernel/locking/rwsem.c:1568 inode_lock_shared include/linux/fs.h:1044 [inline] lookup_slow+0x46/0x70 fs/namei.c:1931 walk_component fs/namei.c:2278 [inline] lookup_last fs/namei.c:2785 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2809 filename_lookup+0x256/0x5d0 fs/namei.c:2838 kern_path+0x3d/0x150 fs/namei.c:3044 is_same_device fs/btrfs/volumes.c:764 [inline] device_list_add+0xfd1/0x2280 fs/btrfs/volumes.c:898 btrfs_scan_one_device+0x3ef/0x680 fs/btrfs/volumes.c:1499 btrfs_get_tree_super fs/btrfs/super.c:1858 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline] btrfs_get_tree+0x4ab/0x1910 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:3758 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3834 do_mount fs/namespace.c:4167 [inline] __do_sys_mount fs/namespace.c:4399 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4376 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0035b9da8a 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:00007f0036b2ce58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f0036b2cee0 RCX: 00007f0035b9da8a RDX: 0000200000000000 RSI: 00002000000015c0 RDI: 00007f0036b2cea0 RBP: 0000200000000000 R08: 00007f0036b2cee0 R09: 0000000002004000 R10: 0000000002004000 R11: 0000000000000246 R12: 00002000000015c0 R13: 00007f0036b2cea0 R14: 000000000000559e R15: 0000200000000180 BTRFS info (device loop1): first mount of filesystem 395ef67a-297e-477c-816d-cd80a5b93e5d BTRFS info (device loop1): using sha256 checksum algorithm BTRFS info (device loop1): rebuilding free space tree BTRFS info (device loop1): enabling ssd optimizations BTRFS info (device loop1): using spread ssd allocation scheme BTRFS info (device loop1): enabling free space tree BTRFS info (device loop1): force clearing of disk cache BTRFS info (device loop1): enabling auto defrag BTRFS info (device loop1): max_inline set to 0 netlink: 'syz.1.5150': attribute type 10 has an invalid length. bridge0: port 2(bridge_slave_1) entered disabled state bridge0: port 1(bridge_slave_0) entered disabled state bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered forwarding state bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered forwarding state bond0: (slave bridge0): Enslaving as an active interface with an up link