======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc6-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor365/5217 is trying to acquire lock:
ffff888021a15258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1673 [inline]
ffff888021a15258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x6d/0x3b0 net/bluetooth/rfcomm/sock.c:73

but task is already holding lock:
ffff888020e32528 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x235/0x720 net/bluetooth/rfcomm/core.c:491

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&d->lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       __rfcomm_dlc_close+0x235/0x720 net/bluetooth/rfcomm/core.c:491
       rfcomm_dlc_close+0x1eb/0x240 net/bluetooth/rfcomm/core.c:524
       __rfcomm_sock_close+0xa7/0x230 net/bluetooth/rfcomm/sock.c:220
       rfcomm_sock_shutdown+0xd5/0x230 net/bluetooth/rfcomm/sock.c:901
       rfcomm_sock_release+0x5d/0x140 net/bluetooth/rfcomm/sock.c:922
       __sock_release+0xb0/0x270 net/socket.c:659
       sock_close+0x1c/0x30 net/socket.c:1421
       __fput+0x270/0xb80 fs/file_table.c:422
       task_work_run+0x14e/0x250 kernel/task_work.c:180
       exit_task_work include/linux/task_work.h:38 [inline]
       do_exit+0xa7d/0x2c10 kernel/exit.c:878
       do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
       get_signal+0x2616/0x2710 kernel/signal.c:2911
       arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
       exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x14a/0x2a0 kernel/entry/common.c:218
       do_syscall_64+0xdc/0x260 arch/x86/entry/common.c:89
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (rfcomm_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       rfcomm_dlc_exists+0x5f/0x1a0 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+0x99d/0x1c60 net/bluetooth/rfcomm/tty.c:587
       rfcomm_sock_ioctl+0xb4/0xe0 net/bluetooth/rfcomm/sock.c:869
       sock_do_ioctl+0x116/0x280 net/socket.c:1222
       sock_ioctl+0x22e/0x6c0 net/socket.c:1341
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:904 [inline]
       __se_sys_ioctl fs/ioctl.c:890 [inline]
       __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (rfcomm_ioctl_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
       rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline]
       rfcomm_dev_ioctl+0x8bd/0x1c60 net/bluetooth/rfcomm/tty.c:587
       rfcomm_sock_ioctl+0xb4/0xe0 net/bluetooth/rfcomm/sock.c:869
       sock_do_ioctl+0x116/0x280 net/socket.c:1222
       sock_ioctl+0x22e/0x6c0 net/socket.c:1341
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:904 [inline]
       __se_sys_ioctl fs/ioctl.c:890 [inline]
       __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3535
       lock_sock include/net/sock.h:1673 [inline]
       rfcomm_sk_state_change+0x6d/0x3b0 net/bluetooth/rfcomm/sock.c:73
       __rfcomm_dlc_close+0x28c/0x720 net/bluetooth/rfcomm/core.c:493
       rfcomm_dlc_close+0x1eb/0x240 net/bluetooth/rfcomm/core.c:524
       __rfcomm_sock_close+0xa7/0x230 net/bluetooth/rfcomm/sock.c:220
       rfcomm_sock_shutdown+0xd5/0x230 net/bluetooth/rfcomm/sock.c:901
       rfcomm_sock_release+0x5d/0x140 net/bluetooth/rfcomm/sock.c:922
       __sock_release+0xb0/0x270 net/socket.c:659
       sock_close+0x1c/0x30 net/socket.c:1421
       __fput+0x270/0xb80 fs/file_table.c:422
       task_work_run+0x14e/0x250 kernel/task_work.c:180
       exit_task_work include/linux/task_work.h:38 [inline]
       do_exit+0xa7d/0x2c10 kernel/exit.c:878
       do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
       get_signal+0x2616/0x2710 kernel/signal.c:2911
       arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
       exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x14a/0x2a0 kernel/entry/common.c:218
       do_syscall_64+0xdc/0x260 arch/x86/entry/common.c:89
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

3 locks held by syz-executor365/5217:
 #0: ffff88802ff06210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:795 [inline]
 #0: ffff88802ff06210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release+0x86/0x270 net/socket.c:658
 #1: ffffffff8f58a4a8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x33/0x240 net/bluetooth/rfcomm/core.c:511
 #2: ffff888020e32528 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x235/0x720 net/bluetooth/rfcomm/core.c:491

stack backtrace:
CPU: 3 PID: 5217 Comm: syz-executor365 Not tainted 6.9.0-rc6-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 check_noncircular+0x31a/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:3869 [inline]
 __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
 lock_sock_nested+0x3a/0xf0 net/core/sock.c:3535
 lock_sock include/net/sock.h:1673 [inline]
 rfcomm_sk_state_change+0x6d/0x3b0 net/bluetooth/rfcomm/sock.c:73
 __rfcomm_dlc_close+0x28c/0x720 net/bluetooth/rfcomm/core.c:493
 rfcomm_dlc_close+0x1eb/0x240 net/bluetooth/rfcomm/core.c:524
 __rfcomm_sock_close+0xa7/0x230 net/bluetooth/rfcomm/sock.c:220
 rfcomm_sock_shutdown+0xd5/0x230 net/bluetooth/rfcomm/sock.c:901
 rfcomm_sock_release+0x5d/0x140 net/bluetooth/rfcomm/sock.c:922
 __sock_release+0xb0/0x270 net/socket.c:659
 sock_close+0x1c/0x30 net/socket.c:1421
 __fput+0x270/0xb80 fs/file_table.c:422
 task_work_run+0x14e/0x250 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xa7d/0x2c10 kernel/exit.c:878
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
 get_signal+0x2616/0x2710 kernel/signal.c:2911
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x14a/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xdc/0x260 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f547d7affb9
Code: Unable to access opcode bytes at 0x7f547d7aff8f.
RSP: 002b:00007ffec889f0a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000000000 RCX: 00007f547d7affb9
RDX: 000000000000000a RSI: 0000000020000040 RDI: 0000000000000003
RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000555567cff370
R13: 0000000000000003 R14: 00007ffec889f120 R15: 00007ffec889f110
 </TASK>