====================================================== WARNING: possible circular locking dependency detected 5.15.140-syzkaller #0 Not tainted ------------------------------------------------------ udevd/8612 is trying to acquire lock: ffff0000dcb38118 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0xa0/0x128 mm/memory.c:5323 but task is already holding lock: ffff0000c08888b0 (&type->i_mutex_dir_key#2){++++}-{3:3}, at: iterate_dir+0x108/0x4e4 fs/readdir.c:55 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&type->i_mutex_dir_key#2){++++}-{3:3}: down_read+0xc0/0x398 kernel/locking/rwsem.c:1488 inode_lock_shared include/linux/fs.h:797 [inline] lookup_slow+0x50/0x84 fs/namei.c:1675 walk_component+0x394/0x4cc fs/namei.c:1972 lookup_last fs/namei.c:2427 [inline] path_lookupat+0x13c/0x3d0 fs/namei.c:2451 filename_lookup+0x1c4/0x4c8 fs/namei.c:2480 kern_path+0x4c/0x194 fs/namei.c:2570 lookup_bdev+0xc0/0x25c block/bdev.c:979 device_matched fs/btrfs/volumes.c:563 [inline] btrfs_free_stale_devices+0x61c/0x9ec fs/btrfs/volumes.c:608 btrfs_scan_one_device+0x438/0x5f8 fs/btrfs/volumes.c:1448 btrfs_control_ioctl+0xe0/0x248 fs/btrfs/super.c:2455 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #3 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 btrfs_run_dev_stats+0xe4/0xe24 fs/btrfs/volumes.c:7930 commit_cowonly_roots+0x17c/0x808 fs/btrfs/transaction.c:1290 btrfs_commit_transaction+0xef4/0x30f0 fs/btrfs/transaction.c:2392 btrfs_commit_super+0xb4/0xd0 fs/btrfs/disk-io.c:4326 close_ctree+0x378/0x860 fs/btrfs/disk-io.c:4438 btrfs_put_super+0x40/0x50 fs/btrfs/super.c:340 generic_shutdown_super+0x130/0x29c fs/super.c:475 kill_anon_super+0x4c/0x74 fs/super.c:1076 btrfs_kill_super+0x40/0x58 fs/btrfs/super.c:2391 deactivate_locked_super+0xb8/0x13c fs/super.c:335 deactivate_super+0x108/0x128 fs/super.c:366 cleanup_mnt+0x3c0/0x474 fs/namespace.c:1143 __cleanup_mnt+0x20/0x30 fs/namespace.c:1150 task_work_run+0x130/0x1e4 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] do_notify_resume+0x262c/0x32b8 arch/arm64/kernel/signal.c:946 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline] el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #2 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __lock_release kernel/locking/lockdep.c:5338 [inline] lock_release+0x340/0xa1c kernel/locking/lockdep.c:5642 __mutex_unlock_slowpath+0xe0/0x6d4 kernel/locking/mutex.c:851 mutex_unlock+0x8c/0xe0 kernel/locking/mutex.c:536 btrfs_commit_transaction+0x1650/0x30f0 fs/btrfs/transaction.c:2439 btrfs_commit_super+0xb4/0xd0 fs/btrfs/disk-io.c:4326 close_ctree+0x378/0x860 fs/btrfs/disk-io.c:4438 btrfs_put_super+0x40/0x50 fs/btrfs/super.c:340 generic_shutdown_super+0x130/0x29c fs/super.c:475 kill_anon_super+0x4c/0x74 fs/super.c:1076 btrfs_kill_super+0x40/0x58 fs/btrfs/super.c:2391 deactivate_locked_super+0xb8/0x13c fs/super.c:335 deactivate_super+0x108/0x128 fs/super.c:366 cleanup_mnt+0x3c0/0x474 fs/namespace.c:1143 __cleanup_mnt+0x20/0x30 fs/namespace.c:1150 task_work_run+0x130/0x1e4 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] do_notify_resume+0x262c/0x32b8 arch/arm64/kernel/signal.c:946 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline] el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #1 (sb_internal#2){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1742 [inline] sb_start_intwrite include/linux/fs.h:1859 [inline] start_transaction+0x644/0x1480 fs/btrfs/transaction.c:678 btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:791 btrfs_dirty_inode+0xb4/0x1c0 fs/btrfs/inode.c:6329 btrfs_update_time+0x248/0x270 fs/btrfs/inode.c:6371 inode_update_time fs/inode.c:1829 [inline] touch_atime+0x434/0xa4c fs/inode.c:1902 file_accessed include/linux/fs.h:2447 [inline] btrfs_file_mmap+0xb0/0x11c fs/btrfs/file.c:2424 call_mmap include/linux/fs.h:2108 [inline] mmap_region+0xcb4/0x12f0 mm/mmap.c:1791 do_mmap+0x6c0/0xcec mm/mmap.c:1575 vm_mmap_pgoff+0x1a4/0x2b4 mm/util.c:551 ksys_mmap_pgoff+0x458/0x668 mm/mmap.c:1624 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline] __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline] __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #0 (&mm->mmap_lock){++++}-{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:3787 [inline] __lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622 __might_fault+0xc8/0x128 mm/memory.c:5324 filldir64+0x2bc/0x9e4 fs/readdir.c:335 dir_emit_dot include/linux/fs.h:3607 [inline] dir_emit_dots include/linux/fs.h:3618 [inline] dcache_readdir+0x134/0x678 fs/libfs.c:196 iterate_dir+0x1f4/0x4e4 __do_sys_getdents64 fs/readdir.c:369 [inline] __se_sys_getdents64 fs/readdir.c:354 [inline] __arm64_sys_getdents64+0x1c4/0x4c4 fs/readdir.c:354 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 other info that might help us debug this: Chain exists of: &mm->mmap_lock --> &fs_devs->device_list_mutex --> &type->i_mutex_dir_key#2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&type->i_mutex_dir_key#2); lock(&fs_devs->device_list_mutex); lock(&type->i_mutex_dir_key#2); lock(&mm->mmap_lock); *** DEADLOCK *** 2 locks held by udevd/8612: #0: ffff0000d5e16ff0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x128/0x170 fs/file.c:1088 #1: ffff0000c08888b0 (&type->i_mutex_dir_key#2){++++}-{3:3}, at: iterate_dir+0x108/0x4e4 fs/readdir.c:55 stack backtrace: CPU: 0 PID: 8612 Comm: udevd Not tainted 5.15.140-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011 check_noncircular+0x2cc/0x378 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:3787 [inline] __lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622 __might_fault+0xc8/0x128 mm/memory.c:5324 filldir64+0x2bc/0x9e4 fs/readdir.c:335 dir_emit_dot include/linux/fs.h:3607 [inline] dir_emit_dots include/linux/fs.h:3618 [inline] dcache_readdir+0x134/0x678 fs/libfs.c:196 iterate_dir+0x1f4/0x4e4 __do_sys_getdents64 fs/readdir.c:369 [inline] __se_sys_getdents64 fs/readdir.c:354 [inline] __arm64_sys_getdents64+0x1c4/0x4c4 fs/readdir.c:354 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584