syzbot

======================================================
WARNING: possible circular locking dependency detected
5.15.153-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor344/3528 is trying to acquire lock:
ffff8880727aa120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1668 [inline]
ffff8880727aa120 (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:
ffff88801ae40d28 (&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:

-> #3 (&d->lock){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       __rfcomm_dlc_close+0x259/0x6d0 net/bluetooth/rfcomm/core.c:487
       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:912
       rfcomm_sock_release+0x55/0x110 net/bluetooth/rfcomm/sock.c:933
       __sock_release net/socket.c:649 [inline]
       sock_close+0xcd/0x230 net/socket.c:1336
       __fput+0x3bf/0x890 fs/file_table.c:280
       task_work_run+0x129/0x1a0 kernel/task_work.c:164
       exit_task_work include/linux/task_work.h:32 [inline]
       do_exit+0x6a3/0x2480 kernel/exit.c:872
       do_group_exit+0x144/0x310 kernel/exit.c:994
       get_signal+0xc66/0x14e0 kernel/signal.c:2889
       arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867
       handle_signal_work kernel/entry/common.c:148 [inline]
       exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:172
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
       __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
       syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301
       do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #2 (rfcomm_mutex){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       rfcomm_dlc_exists+0xa2/0x370 net/bluetooth/rfcomm/core.c:542
       __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:415 [inline]
       rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline]
       rfcomm_dev_ioctl+0xb2d/0x2180 net/bluetooth/rfcomm/tty.c:588
       rfcomm_sock_ioctl+0x82/0xc0 net/bluetooth/rfcomm/sock.c:880
       sock_do_ioctl+0x11d/0x5a0 net/socket.c:1140
       sock_ioctl+0x47f/0x770 net/socket.c:1257
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #1 (rfcomm_ioctl_mutex){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline]
       rfcomm_dev_ioctl+0x233/0x2180 net/bluetooth/rfcomm/tty.c:588
       rfcomm_sock_ioctl+0x82/0xc0 net/bluetooth/rfcomm/sock.c:880
       sock_do_ioctl+0x11d/0x5a0 net/socket.c:1140
       sock_ioctl+0x47f/0x770 net/socket.c:1257
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       lock_sock_nested+0x44/0x100 net/core/sock.c:3250
       lock_sock include/net/sock.h:1668 [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:912
       rfcomm_sock_release+0x55/0x110 net/bluetooth/rfcomm/sock.c:933
       __sock_release net/socket.c:649 [inline]
       sock_close+0xcd/0x230 net/socket.c:1336
       __fput+0x3bf/0x890 fs/file_table.c:280
       task_work_run+0x129/0x1a0 kernel/task_work.c:164
       exit_task_work include/linux/task_work.h:32 [inline]
       do_exit+0x6a3/0x2480 kernel/exit.c:872
       do_group_exit+0x144/0x310 kernel/exit.c:994
       get_signal+0xc66/0x14e0 kernel/signal.c:2889
       arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867
       handle_signal_work kernel/entry/common.c:148 [inline]
       exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:172
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
       __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
       syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301
       do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

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-executor344/3528:
 #0: ffff88807167a610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #0: ffff88807167a610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline]
 #0: ffff88807167a610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1336
 #1: ffffffff8db43ee8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x37/0x180 net/bluetooth/rfcomm/core.c:507
 #2: ffff88801ae40d28 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x259/0x6d0 net/bluetooth/rfcomm/core.c:487

stack backtrace:
CPU: 1 PID: 3528 Comm: syz-executor344 Not tainted 5.15.153-syzkaller #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+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 lock_sock_nested+0x44/0x100 net/core/sock.c:3250
 lock_sock include/net/sock.h:1668 [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:912
 rfcomm_sock_release+0x55/0x110 net/bluetooth/rfcomm/sock.c:933
 __sock_release net/socket.c:649 [inline]
 sock_close+0xcd/0x230 net/socket.c:1336
 __fput+0x3bf/0x890 fs/file_table.c:280
 task_work_run+0x129/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0x6a3/0x2480 kernel/exit.c:872
 do_group_exit+0x144/0x310 kernel/exit.c:994
 get_signal+0xc66/0x14e0 kernel/signal.c:2889
 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:172
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f9549e2af79
Code: Unable to access opcode bytes at RIP 0x7f9549e2af4f.
RSP: 002b:00007fffa92eba38 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000000000 RCX: 00007f9549e2af79
RDX: 000000000000000a RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000555556f1f370
R13: 0000000000000001 R14: 00007fffa92ebab0 R15: 00007fffa92ebaa0
 </TASK>