======================================================
WARNING: possible circular locking dependency detected
6.1.96-syzkaller #0 Not tainted
------------------------------------------------------
syz.3.716/6436 is trying to acquire lock:
ffff0000c4136130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1748 [inline]
ffff0000c4136130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x60/0x2c8 net/bluetooth/rfcomm/sock.c:73

but task is already holding lock:
ffff0000d32b5d28 (&d->lock#2){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x1f8/0x600 net/bluetooth/rfcomm/core.c:487

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&d->lock#2){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       __rfcomm_dlc_close+0x1f8/0x600 net/bluetooth/rfcomm/core.c:487
       rfcomm_dlc_close+0x100/0x194 net/bluetooth/rfcomm/core.c:520
       __rfcomm_sock_close+0x138/0x258 net/bluetooth/rfcomm/sock.c:220
       rfcomm_sock_shutdown+0xa8/0x214 net/bluetooth/rfcomm/sock.c:905
       rfcomm_sock_release+0x58/0x114 net/bluetooth/rfcomm/sock.c:926
       __sock_release net/socket.c:654 [inline]
       sock_close+0xb8/0x1fc net/socket.c:1400
       __fput+0x30c/0x7bc fs/file_table.c:320
       ____fput+0x20/0x30 fs/file_table.c:348
       task_work_run+0x240/0x2f0 kernel/task_work.c:179
       exit_task_work include/linux/task_work.h:38 [inline]
       do_exit+0x554/0x1a88 kernel/exit.c:869
       do_group_exit+0x194/0x22c kernel/exit.c:1019
       get_signal+0x14a0/0x158c kernel/signal.c:2862
       do_signal arch/arm64/kernel/signal.c:1076 [inline]
       do_notify_resume+0x3ac/0x3474 arch/arm64/kernel/signal.c:1129
       prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
       exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
       el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #2 (rfcomm_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       rfcomm_dlc_exists+0xb0/0x32c net/bluetooth/rfcomm/core.c:542
       __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:414 [inline]
       rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline]
       rfcomm_dev_ioctl+0x888/0x22a8 net/bluetooth/rfcomm/tty.c:587
       rfcomm_sock_ioctl+0x98/0xf0 net/bluetooth/rfcomm/sock.c:873
       sock_do_ioctl+0x134/0x2dc net/socket.c:1204
       sock_ioctl+0x4ec/0x858 net/socket.c:1321
       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+0x64/0x218 arch/arm64/kernel/syscall.c:206
       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+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #1 (rfcomm_ioctl_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline]
       rfcomm_dev_ioctl+0x258/0x22a8 net/bluetooth/rfcomm/tty.c:587
       rfcomm_sock_ioctl+0x98/0xf0 net/bluetooth/rfcomm/sock.c:873
       sock_do_ioctl+0x134/0x2dc net/socket.c:1204
       sock_ioctl+0x4ec/0x858 net/socket.c:1321
       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+0x64/0x218 arch/arm64/kernel/syscall.c:206
       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+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
       lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
       lock_sock_nested+0x78/0x138 net/core/sock.c:3485
       lock_sock include/net/sock.h:1748 [inline]
       rfcomm_sk_state_change+0x60/0x2c8 net/bluetooth/rfcomm/sock.c:73
       __rfcomm_dlc_close+0x234/0x600 net/bluetooth/rfcomm/core.c:489
       rfcomm_dlc_close+0x100/0x194 net/bluetooth/rfcomm/core.c:520
       __rfcomm_sock_close+0x138/0x258 net/bluetooth/rfcomm/sock.c:220
       rfcomm_sock_shutdown+0xa8/0x214 net/bluetooth/rfcomm/sock.c:905
       rfcomm_sock_release+0x58/0x114 net/bluetooth/rfcomm/sock.c:926
       __sock_release net/socket.c:654 [inline]
       sock_close+0xb8/0x1fc net/socket.c:1400
       __fput+0x30c/0x7bc fs/file_table.c:320
       ____fput+0x20/0x30 fs/file_table.c:348
       task_work_run+0x240/0x2f0 kernel/task_work.c:179
       exit_task_work include/linux/task_work.h:38 [inline]
       do_exit+0x554/0x1a88 kernel/exit.c:869
       do_group_exit+0x194/0x22c kernel/exit.c:1019
       get_signal+0x14a0/0x158c kernel/signal.c:2862
       do_signal arch/arm64/kernel/signal.c:1076 [inline]
       do_notify_resume+0x3ac/0x3474 arch/arm64/kernel/signal.c:1129
       prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
       exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
       el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM --> rfcomm_mutex --> &d->lock#2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&d->lock#2);
                               lock(rfcomm_mutex);
                               lock(&d->lock#2);
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM);

 *** DEADLOCK ***

3 locks held by syz.3.716/6436:
 #0: ffff0000ec5bd610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #0: ffff0000ec5bd610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline]
 #0: ffff0000ec5bd610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x80/0x1fc net/socket.c:1400
 #1: ffff800017fa4068 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x44/0x194 net/bluetooth/rfcomm/core.c:507
 #2: ffff0000d32b5d28 (&d->lock#2){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x1f8/0x600 net/bluetooth/rfcomm/core.c:487

stack backtrace:
CPU: 0 PID: 6436 Comm: syz.3.716 Not tainted 6.1.96-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
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+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2048
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
 lock_sock_nested+0x78/0x138 net/core/sock.c:3485
 lock_sock include/net/sock.h:1748 [inline]
 rfcomm_sk_state_change+0x60/0x2c8 net/bluetooth/rfcomm/sock.c:73
 __rfcomm_dlc_close+0x234/0x600 net/bluetooth/rfcomm/core.c:489
 rfcomm_dlc_close+0x100/0x194 net/bluetooth/rfcomm/core.c:520
 __rfcomm_sock_close+0x138/0x258 net/bluetooth/rfcomm/sock.c:220
 rfcomm_sock_shutdown+0xa8/0x214 net/bluetooth/rfcomm/sock.c:905
 rfcomm_sock_release+0x58/0x114 net/bluetooth/rfcomm/sock.c:926
 __sock_release net/socket.c:654 [inline]
 sock_close+0xb8/0x1fc net/socket.c:1400
 __fput+0x30c/0x7bc fs/file_table.c:320
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x240/0x2f0 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x554/0x1a88 kernel/exit.c:869
 do_group_exit+0x194/0x22c kernel/exit.c:1019
 get_signal+0x14a0/0x158c kernel/signal.c:2862
 do_signal arch/arm64/kernel/signal.c:1076 [inline]
 do_notify_resume+0x3ac/0x3474 arch/arm64/kernel/signal.c:1129
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585