====================================================== WARNING: possible circular locking dependency detected 6.1.103-syzkaller #0 Not tainted ------------------------------------------------------ syz.0.1686/10569 is trying to acquire lock: ffff8880591f9130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1748 [inline] ffff8880591f9130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x57/0x300 net/bluetooth/rfcomm/sock.c:73 but task is already holding lock: ffff8880596ce128 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x259/0x6d0 net/bluetooth/rfcomm/core.c:487 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&d->lock){+.+.}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747 __rfcomm_dev_add net/bluetooth/rfcomm/tty.c:277 [inline] rfcomm_dev_add net/bluetooth/rfcomm/tty.c:325 [inline] __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:424 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline] rfcomm_dev_ioctl+0x14f8/0x2180 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0x82/0xc0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x152/0x450 net/socket.c:1204 sock_ioctl+0x47f/0x770 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (rfcomm_dev_lock){+.+.}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747 rfcomm_get_dev_list net/bluetooth/rfcomm/tty.c:526 [inline] rfcomm_dev_ioctl+0x556/0x2180 net/bluetooth/rfcomm/tty.c:593 rfcomm_sock_ioctl+0x82/0xc0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x152/0x450 net/socket.c:1204 sock_ioctl+0x47f/0x770 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #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+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 lock_sock_nested+0x44/0x100 net/core/sock.c:3485 lock_sock include/net/sock.h:1748 [inline] rfcomm_sk_state_change+0x57/0x300 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x2b2/0x6d0 net/bluetooth/rfcomm/core.c:489 rfcomm_dlc_close+0xed/0x180 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0x104/0x220 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xb4/0x230 net/bluetooth/rfcomm/sock.c:905 rfcomm_sock_release+0x55/0x110 net/bluetooth/rfcomm/sock.c:926 __sock_release net/socket.c:654 [inline] sock_close+0xcd/0x230 net/socket.c:1400 __fput+0x3f6/0x8d0 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0xa73/0x26a0 kernel/exit.c:871 do_group_exit+0x202/0x2b0 kernel/exit.c:1021 get_signal+0x16f7/0x17d0 kernel/signal.c:2870 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM --> rfcomm_dev_lock --> &d->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&d->lock); lock(rfcomm_dev_lock); lock(&d->lock); lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); *** DEADLOCK *** 3 locks held by syz.0.1686/10569: #0: ffff8880524bbe10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #0: ffff8880524bbe10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline] #0: ffff8880524bbe10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1400 #1: ffffffff8e6733a8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x37/0x180 net/bluetooth/rfcomm/core.c:507 #2: ffff8880596ce128 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x259/0x6d0 net/bluetooth/rfcomm/core.c:487 stack backtrace: CPU: 1 PID: 10569 Comm: syz.0.1686 Not tainted 6.1.103-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2fa/0x3b0 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+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 lock_sock_nested+0x44/0x100 net/core/sock.c:3485 lock_sock include/net/sock.h:1748 [inline] rfcomm_sk_state_change+0x57/0x300 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x2b2/0x6d0 net/bluetooth/rfcomm/core.c:489 rfcomm_dlc_close+0xed/0x180 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0x104/0x220 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xb4/0x230 net/bluetooth/rfcomm/sock.c:905 rfcomm_sock_release+0x55/0x110 net/bluetooth/rfcomm/sock.c:926 __sock_release net/socket.c:654 [inline] sock_close+0xcd/0x230 net/socket.c:1400 __fput+0x3f6/0x8d0 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0xa73/0x26a0 kernel/exit.c:871 do_group_exit+0x202/0x2b0 kernel/exit.c:1021 get_signal+0x16f7/0x17d0 kernel/signal.c:2870 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f69d19779f9 Code: Unable to access opcode bytes at 0x7f69d19779cf. RSP: 002b:00007f69d26e10f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f69d1b06060 RCX: 00007f69d19779f9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f69d1b06060 RBP: 00007f69d1b06058 R08: 00007f69d26e16c0 R09: 00007f69d26e16c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f69d1b06064 R13: 000000000000006e R14: 00007fff10da5bf0 R15: 00007fff10da5cd8