loop3: detected capacity change from 0 to 32768 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.3.2346/15804 is trying to acquire lock: ffff88807e2849f0 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline] ffff88807e2849f0 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1874 but task is already holding lock: ffff8880532150d8 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: device_list_add+0x595/0x22b0 fs/btrfs/volumes.c:838 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:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 insert_dev_extents fs/btrfs/block-group.c:2748 [inline] btrfs_create_pending_block_groups+0x5f8/0x1760 fs/btrfs/block-group.c:2799 __btrfs_end_transaction+0x140/0x640 fs/btrfs/transaction.c:1078 btrfs_inc_block_group_ro+0x63e/0x6f0 fs/btrfs/block-group.c:3086 btrfs_relocate_block_group+0x3f1/0xc70 fs/btrfs/relocation.c:3923 btrfs_relocate_chunk+0x12f/0x5c0 fs/btrfs/volumes.c:3424 __btrfs_balance+0x18ff/0x24e0 fs/btrfs/volumes.c:4197 btrfs_balance+0xac2/0x11b0 fs/btrfs/volumes.c:4571 btrfs_ioctl_balance+0x3d3/0x610 fs/btrfs/ioctl.c:3525 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+0xec/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:323 start_transaction+0x6b7/0x15f0 fs/btrfs/transaction.c:707 btrfs_rebuild_free_space_tree+0xad/0x6c0 fs/btrfs/free-space-tree.c:1330 btrfs_start_pre_rw_mount+0x128f/0x1bf0 fs/btrfs/disk-io.c:3052 open_ctree+0x2b11/0x3d20 fs/btrfs/disk-io.c:3603 btrfs_fill_super fs/btrfs/super.c:983 [inline] btrfs_get_tree_super fs/btrfs/super.c:1946 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2089 [inline] btrfs_get_tree+0x1061/0x1920 fs/btrfs/super.c:2123 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 -> #2 (btrfs_trans_num_writers){++++}-{0:0}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x19a/0x3b0 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:1083 btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6338 inode_update_time fs/inode.c:2167 [inline] touch_atime+0x2f9/0x6d0 fs/inode.c:2240 file_accessed include/linux/fs.h:2254 [inline] btrfs_file_mmap_prepare+0x176/0x1f0 fs/btrfs/file.c:2053 vfs_mmap_prepare include/linux/fs.h:2058 [inline] call_mmap_prepare mm/vma.c:2596 [inline] __mmap_region mm/vma.c:2692 [inline] mmap_region+0xb2b/0x1d10 mm/vma.c:2786 do_mmap+0xc45/0x10d0 mm/mmap.c:558 vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:581 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604 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 (&mm->mmap_lock){++++}-{4:4}: down_read_killable+0x50/0x350 kernel/locking/rwsem.c:1560 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:400 get_mmap_lock_carefully mm/mmap_lock.c:399 [inline] lock_mm_and_find_vma+0x2a8/0x300 mm/mmap_lock.c:450 do_user_addr_fault+0x331/0x1380 arch/x86/mm/fault.c:1359 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 filldir+0x2b6/0x6c0 fs/readdir.c:295 dir_emit include/linux/fs.h:3527 [inline] offset_dir_emit fs/libfs.c:499 [inline] offset_iterate_dir fs/libfs.c:515 [inline] offset_readdir+0x44c/0x560 fs/libfs.c:564 iterate_dir+0x399/0x570 fs/readdir.c:108 __do_sys_getdents fs/readdir.c:326 [inline] __se_sys_getdents+0xe4/0x250 fs/readdir.c:312 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 (&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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 down_read+0x47/0x2e0 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:1042 [inline] lookup_slow+0x46/0x70 fs/namei.c:1874 walk_component fs/namei.c:2221 [inline] lookup_last fs/namei.c:2722 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2746 filename_lookup+0x212/0x570 fs/namei.c:2775 kern_path+0x35/0x50 fs/namei.c:2987 is_same_device fs/btrfs/volumes.c:759 [inline] device_list_add+0xe21/0x22b0 fs/btrfs/volumes.c:893 btrfs_scan_one_device+0x3ef/0x680 fs/btrfs/volumes.c:1492 btrfs_get_tree_super fs/btrfs/super.c:1860 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2089 [inline] btrfs_get_tree+0x4ab/0x1920 fs/btrfs/super.c:2123 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 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.3.2346/15804: #0: ffffffff8e5133e8 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree_super fs/btrfs/super.c:1854 [inline] #0: ffffffff8e5133e8 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree_subvol fs/btrfs/super.c:2089 [inline] #0: ffffffff8e5133e8 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree+0x47c/0x1920 fs/btrfs/super.c:2123 #1: ffff8880532150d8 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: device_list_add+0x595/0x22b0 fs/btrfs/volumes.c:838 stack backtrace: CPU: 1 UID: 0 PID: 15804 Comm: syz.3.2346 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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 down_read+0x47/0x2e0 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:1042 [inline] lookup_slow+0x46/0x70 fs/namei.c:1874 walk_component fs/namei.c:2221 [inline] lookup_last fs/namei.c:2722 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2746 filename_lookup+0x212/0x570 fs/namei.c:2775 kern_path+0x35/0x50 fs/namei.c:2987 is_same_device fs/btrfs/volumes.c:759 [inline] device_list_add+0xe21/0x22b0 fs/btrfs/volumes.c:893 btrfs_scan_one_device+0x3ef/0x680 fs/btrfs/volumes.c:1492 btrfs_get_tree_super fs/btrfs/super.c:1860 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2089 [inline] btrfs_get_tree+0x4ab/0x1920 fs/btrfs/super.c:2123 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 RIP: 0033:0x7fe367b90eea Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe368986e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fe368986ef0 RCX: 00007fe367b90eea RDX: 0000200000000000 RSI: 0000200000000100 RDI: 00007fe368986eb0 RBP: 0000200000000000 R08: 00007fe368986ef0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000100 R13: 00007fe368986eb0 R14: 000000000000559e R15: 00002000000002c0 BTRFS info (device loop3): first mount of filesystem 395ef67a-297e-477c-816d-cd80a5b93e5d BTRFS info (device loop3): using sha256 (sha256-lib) checksum algorithm BTRFS info (device loop3): checking UUID tree BTRFS info (device loop3): enabling ssd optimizations BTRFS info (device loop3): turning on async discard BTRFS info (device loop3): enabling free space tree BTRFS info (device loop3): last unmount of filesystem 395ef67a-297e-477c-816d-cd80a5b93e5d loop3: detected capacity change from 0 to 512 EXT4-fs: Ignoring removed oldalloc option EXT4-fs (loop3): can't mount with data=, fs mounted w/o journal loop3: detected capacity change from 0 to 32768 xfs: Deprecated parameter 'noikeep' XFS: noikeep mount option is deprecated. XFS (loop3): DAX unsupported by block device. Turning off DAX. XFS (loop3): Mounting V5 Filesystem c496e05e-540d-4c72-b591-04d79d8b4eeb XFS (loop3): Ending clean mount XFS (loop3): Quotacheck needed: Please wait. XFS (loop3): Quotacheck: Unsuccessful (Error -117): Disabling quotas.