====================================================== WARNING: possible circular locking dependency detected 6.7.0-rc2-syzkaller-00099-gc9213ddad2bd #0 Not tainted ------------------------------------------------------ syz-executor358/5113 is trying to acquire lock: ffffffff8ed3b648 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_exists+0x5b/0x190 net/bluetooth/rfcomm/core.c:546 but task is already holding lock: ffffffff8ed405c8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] ffffffff8ed405c8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x8b9/0x1c50 net/bluetooth/rfcomm/tty.c:587 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (rfcomm_ioctl_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:747 rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] rfcomm_dev_ioctl+0x8b9/0x1c50 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0xb0/0xe0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x113/0x270 net/socket.c:1220 sock_ioctl+0x22e/0x6b0 net/socket.c:1339 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b -> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}: lock_sock_nested+0x3a/0xf0 net/core/sock.c:3519 lock_sock include/net/sock.h:1720 [inline] rfcomm_sk_state_change+0x6d/0x3a0 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x285/0x720 net/bluetooth/rfcomm/core.c:493 rfcomm_dlc_close+0x1e7/0x240 net/bluetooth/rfcomm/core.c:524 __rfcomm_sock_close+0xa7/0x230 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xd1/0x230 net/bluetooth/rfcomm/sock.c:905 rfcomm_sock_release+0x5d/0x140 net/bluetooth/rfcomm/sock.c:926 __sock_release+0xae/0x260 net/socket.c:659 sock_close+0x1c/0x20 net/socket.c:1419 __fput+0x270/0xbb0 fs/file_table.c:394 task_work_run+0x14d/0x240 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa92/0x2ae0 kernel/exit.c:871 do_group_exit+0xd4/0x2a0 kernel/exit.c:1021 get_signal+0x23be/0x2790 kernel/signal.c:2904 arch_do_signal_or_restart+0x90/0x7f0 arch/x86/kernel/signal.c:309 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x121/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1e/0x60 kernel/entry/common.c:296 do_syscall_64+0x4d/0x110 arch/x86/entry/common.c:88 entry_SYSCALL_64_after_hwframe+0x63/0x6b -> #1 (&d->lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:747 __rfcomm_dlc_close+0x231/0x720 net/bluetooth/rfcomm/core.c:491 rfcomm_dlc_close+0x1e7/0x240 net/bluetooth/rfcomm/core.c:524 __rfcomm_sock_close+0xa7/0x230 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xd1/0x230 net/bluetooth/rfcomm/sock.c:905 rfcomm_sock_release+0x5d/0x140 net/bluetooth/rfcomm/sock.c:926 __sock_release+0xae/0x260 net/socket.c:659 sock_close+0x1c/0x20 net/socket.c:1419 __fput+0x270/0xbb0 fs/file_table.c:394 task_work_run+0x14d/0x240 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa92/0x2ae0 kernel/exit.c:871 do_group_exit+0xd4/0x2a0 kernel/exit.c:1021 get_signal+0x23be/0x2790 kernel/signal.c:2904 arch_do_signal_or_restart+0x90/0x7f0 arch/x86/kernel/signal.c:309 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x121/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1e/0x60 kernel/entry/common.c:296 do_syscall_64+0x4d/0x110 arch/x86/entry/common.c:88 entry_SYSCALL_64_after_hwframe+0x63/0x6b -> #0 (rfcomm_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2464/0x3b10 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5718 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:747 rfcomm_dlc_exists+0x5b/0x190 net/bluetooth/rfcomm/core.c:546 __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:414 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline] rfcomm_dev_ioctl+0x999/0x1c50 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0xb0/0xe0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x113/0x270 net/socket.c:1220 sock_ioctl+0x22e/0x6b0 net/socket.c:1339 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b other info that might help us debug this: Chain exists of: rfcomm_mutex --> sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM --> rfcomm_ioctl_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rfcomm_ioctl_mutex); lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); lock(rfcomm_ioctl_mutex); lock(rfcomm_mutex); *** DEADLOCK *** 2 locks held by syz-executor358/5113: #0: ffff888015add130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1720 [inline] #0: ffff888015add130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_ioctl+0xa3/0xe0 net/bluetooth/rfcomm/sock.c:872 #1: ffffffff8ed405c8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] #1: ffffffff8ed405c8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x8b9/0x1c50 net/bluetooth/rfcomm/tty.c:587 stack backtrace: CPU: 1 PID: 5113 Comm: syz-executor358 Not tainted 6.7.0-rc2-syzkaller-00099-gc9213ddad2bd #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_noncircular+0x317/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2464/0x3b10 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5718 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:747 rfcomm_dlc_exists+0x5b/0x190 net/bluetooth/rfcomm/core.c:546 __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:414 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline] rfcomm_dev_ioctl+0x999/0x1c50 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0xb0/0xe0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x113/0x270 net/socket.c:1220 sock_ioctl+0x22e/0x6b0 net/socket.c:1339 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f8026c9aff9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 19 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffcb8a9b718 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8026c9aff9 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000005 RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000161ff R13: 00007ffcb8a9b748 R14: 00007ffcb8a9b7a0 R15: 00007ffcb8a9b790