BTRFS info (device loop4): checking UUID tree ====================================================== WARNING: possible circular locking dependency detected 6.2.0-syzkaller-18300-g2ebd1fbb946d #0 Not tainted ------------------------------------------------------ syz-executor.4/2719 is trying to acquire lock: ffff0000d6156e88 (btrfs-tree-01){++++}-{3:3}, at: __btrfs_tree_read_lock+0x44/0x544 fs/btrfs/locking.c:135 but task is already holding lock: ffff0000d6157268 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x44/0x544 fs/btrfs/locking.c:135 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (btrfs-tree-00){++++}-{3:3}: down_read_nested+0x64/0x84 kernel/locking/rwsem.c:1634 __btrfs_tree_read_lock+0x44/0x544 fs/btrfs/locking.c:135 btrfs_tree_read_lock+0x24/0x34 fs/btrfs/locking.c:141 btrfs_search_slot+0x11e8/0x2a78 fs/btrfs/ctree.c:2249 btrfs_init_root_free_objectid+0x128/0x2e0 fs/btrfs/disk-io.c:5373 btrfs_init_fs_root fs/btrfs/disk-io.c:1561 [inline] btrfs_get_root_ref+0x4a8/0x9c8 fs/btrfs/disk-io.c:1765 btrfs_get_fs_root fs/btrfs/disk-io.c:1817 [inline] open_ctree+0x1ee8/0x24a8 fs/btrfs/disk-io.c:3886 btrfs_fill_super+0x1b4/0x2c8 fs/btrfs/super.c:1151 btrfs_mount_root+0x754/0x868 fs/btrfs/super.c:1520 legacy_get_tree+0xd4/0x16c fs/fs_context.c:610 vfs_get_tree+0x90/0x274 fs/super.c:1489 fc_mount fs/namespace.c:1149 [inline] vfs_kern_mount+0xdc/0x178 fs/namespace.c:1179 btrfs_mount+0x330/0x9c8 fs/btrfs/super.c:1580 legacy_get_tree+0xd4/0x16c fs/fs_context.c:610 vfs_get_tree+0x90/0x274 fs/super.c:1489 do_new_mount+0x25c/0x8c8 fs/namespace.c:3145 path_mount+0x590/0xe58 fs/namespace.c:3475 do_mount fs/namespace.c:3488 [inline] __do_sys_mount fs/namespace.c:3697 [inline] __se_sys_mount fs/namespace.c:3674 [inline] __arm64_sys_mount+0x45c/0x594 fs/namespace.c:3674 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 -> #0 (btrfs-tree-01){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5055 lock_acquire+0x2e8/0x8c0 kernel/locking/lockdep.c:5668 down_read_nested+0x64/0x84 kernel/locking/rwsem.c:1634 __btrfs_tree_read_lock+0x44/0x544 fs/btrfs/locking.c:135 btrfs_tree_read_lock fs/btrfs/locking.c:141 [inline] btrfs_read_lock_root_node+0x254/0x350 fs/btrfs/locking.c:280 btrfs_search_slot_get_root fs/btrfs/ctree.c:1779 [inline] btrfs_search_slot+0x46c/0x2a78 fs/btrfs/ctree.c:2101 btrfs_lookup_inode+0xdc/0x3c8 fs/btrfs/inode-item.c:412 btrfs_read_locked_inode fs/btrfs/inode.c:3983 [inline] btrfs_iget_path+0x298/0x11f8 fs/btrfs/inode.c:5799 btrfs_iget+0x38/0x4c fs/btrfs/inode.c:5821 btrfs_search_path_in_tree_user fs/btrfs/ioctl.c:1960 [inline] btrfs_ioctl_ino_lookup_user+0x5d8/0xd0c fs/btrfs/ioctl.c:2104 btrfs_ioctl+0xa98/0xb08 fs/btrfs/ioctl.c:4668 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-tree-00); lock(btrfs-tree-01); lock(btrfs-tree-00); lock(btrfs-tree-01); *** DEADLOCK *** 1 lock held by syz-executor.4/2719: #0: ffff0000d6157268 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x44/0x544 fs/btrfs/locking.c:135 stack backtrace: CPU: 0 PID: 2719 Comm: syz-executor.4 Not tainted 6.2.0-syzkaller-18300-g2ebd1fbb946d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023 Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2055 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5055 lock_acquire+0x2e8/0x8c0 kernel/locking/lockdep.c:5668 down_read_nested+0x64/0x84 kernel/locking/rwsem.c:1634 __btrfs_tree_read_lock+0x44/0x544 fs/btrfs/locking.c:135 btrfs_tree_read_lock fs/btrfs/locking.c:141 [inline] btrfs_read_lock_root_node+0x254/0x350 fs/btrfs/locking.c:280 btrfs_search_slot_get_root fs/btrfs/ctree.c:1779 [inline] btrfs_search_slot+0x46c/0x2a78 fs/btrfs/ctree.c:2101 btrfs_lookup_inode+0xdc/0x3c8 fs/btrfs/inode-item.c:412 btrfs_read_locked_inode fs/btrfs/inode.c:3983 [inline] btrfs_iget_path+0x298/0x11f8 fs/btrfs/inode.c:5799 btrfs_iget+0x38/0x4c fs/btrfs/inode.c:5821 btrfs_search_path_in_tree_user fs/btrfs/ioctl.c:1960 [inline] btrfs_ioctl_ino_lookup_user+0x5d8/0xd0c fs/btrfs/ioctl.c:2104 btrfs_ioctl+0xa98/0xb08 fs/btrfs/ioctl.c:4668 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591