======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc5-syzkaller-00192-g8953285d7bd6 #0 Not tainted
------------------------------------------------------
syz-executor.3/8471 is trying to acquire lock:
ffffffff8f7321c8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_exists+0xa6/0x380 net/bluetooth/rfcomm/core.c:546

but task is already holding lock:
ffffffff8f735d28 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline]
ffffffff8f735d28 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x237/0x21b0 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}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       rfcomm_release_dev net/bluetooth/rfcomm/tty.c:495 [inline]
       rfcomm_dev_ioctl+0x168/0x21b0 net/bluetooth/rfcomm/tty.c:590
       rfcomm_sock_ioctl+0x86/0xd0 net/bluetooth/rfcomm/sock.c:869
       sock_do_ioctl+0x158/0x460 net/socket.c:1222
       sock_ioctl+0x629/0x8e0 net/socket.c:1341
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:904 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       lock_sock_nested+0x48/0x100 net/core/sock.c:3535
       lock_sock include/net/sock.h:1673 [inline]
       rfcomm_sk_state_change+0x5b/0x310 net/bluetooth/rfcomm/sock.c:73
       __rfcomm_dlc_close+0x26f/0x6a0 net/bluetooth/rfcomm/core.c:493
       rfcomm_dlc_close+0xf1/0x190 net/bluetooth/rfcomm/core.c:524
       __rfcomm_sock_close+0x121/0x250 net/bluetooth/rfcomm/sock.c:220
       rfcomm_sock_shutdown+0xb8/0x240 net/bluetooth/rfcomm/sock.c:901
       __sys_shutdown_sock net/socket.c:2425 [inline]
       __sys_shutdown net/socket.c:2437 [inline]
       __do_sys_shutdown net/socket.c:2445 [inline]
       __se_sys_shutdown+0x14e/0x1b0 net/socket.c:2443
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&d->lock){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       __rfcomm_dlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491
       rfcomm_dlc_close+0xf1/0x190 net/bluetooth/rfcomm/core.c:524
       __rfcomm_sock_close+0x121/0x250 net/bluetooth/rfcomm/sock.c:220
       rfcomm_sock_shutdown+0xb8/0x240 net/bluetooth/rfcomm/sock.c:901
       __sys_shutdown_sock net/socket.c:2425 [inline]
       __sys_shutdown net/socket.c:2437 [inline]
       __do_sys_shutdown net/socket.c:2445 [inline]
       __se_sys_shutdown+0x14e/0x1b0 net/socket.c:2443
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #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+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       rfcomm_dlc_exists+0xa6/0x380 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+0xb31/0x21b0 net/bluetooth/rfcomm/tty.c:587
       rfcomm_sock_ioctl+0x86/0xd0 net/bluetooth/rfcomm/sock.c:869
       sock_do_ioctl+0x158/0x460 net/socket.c:1222
       sock_ioctl+0x629/0x8e0 net/socket.c:1341
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:904 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

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-executor.3/8471:
 #0: ffff88807c876258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1673 [inline]
 #0: ffff88807c876258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_ioctl+0x78/0xd0 net/bluetooth/rfcomm/sock.c:868
 #1: ffffffff8f735d28 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline]
 #1: ffffffff8f735d28 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x237/0x21b0 net/bluetooth/rfcomm/tty.c:587

stack backtrace:
CPU: 0 PID: 8471 Comm: syz-executor.3 Not tainted 6.9.0-rc5-syzkaller-00192-g8953285d7bd6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_noncircular+0x36a/0x4a0 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+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 rfcomm_dlc_exists+0xa6/0x380 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+0xb31/0x21b0 net/bluetooth/rfcomm/tty.c:587
 rfcomm_sock_ioctl+0x86/0xd0 net/bluetooth/rfcomm/sock.c:869
 sock_do_ioctl+0x158/0x460 net/socket.c:1222
 sock_ioctl+0x629/0x8e0 net/socket.c:1341
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6ced27dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f6cee0900c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6ced3abf80 RCX: 00007f6ced27dea9
RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 000000000000000a
RBP: 00007f6ced2ca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f6ced3abf80 R15: 00007ffeed3ce268
 </TASK>