====================================================== WARNING: possible circular locking dependency detected 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted ------------------------------------------------------ syz-executor237/5105 is trying to acquire lock: ffffffff8f58c328 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_exists+0x5f/0x1a0 net/bluetooth/rfcomm/core.c:546 but task is already holding lock: ffffffff8f5912a8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] ffffffff8f5912a8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x8e4/0x1c80 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}: __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+0x8e4/0x1c80 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0xb4/0xe0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x119/0x280 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+0x196/0x220 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd5/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 -> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}: lock_sock_nested+0x3a/0xf0 net/core/sock.c:3535 lock_sock include/net/sock.h:1671 [inline] rfcomm_sk_state_change+0x6d/0x3b0 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x28f/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:905 rfcomm_sock_release+0x5d/0x140 net/bluetooth/rfcomm/sock.c:926 __sock_release+0xb3/0x270 net/socket.c:659 sock_close+0x1c/0x30 net/socket.c:1421 __fput+0x273/0xb80 fs/file_table.c:422 task_work_run+0x151/0x250 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa7d/0x2be0 kernel/exit.c:878 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 get_signal+0x2390/0x2760 kernel/signal.c:2907 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:105 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline] syscall_exit_to_user_mode+0x14a/0x2a0 kernel/entry/common.c:212 do_syscall_64+0xe2/0x260 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6d/0x75 -> #1 (&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:905 rfcomm_sock_release+0x5d/0x140 net/bluetooth/rfcomm/sock.c:926 __sock_release+0xb3/0x270 net/socket.c:659 sock_close+0x1c/0x30 net/socket.c:1421 __fput+0x273/0xb80 fs/file_table.c:422 task_work_run+0x151/0x250 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa7d/0x2be0 kernel/exit.c:878 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 get_signal+0x2390/0x2760 kernel/signal.c:2907 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:105 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline] syscall_exit_to_user_mode+0x14a/0x2a0 kernel/entry/common.c:212 do_syscall_64+0xe2/0x260 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6d/0x75 -> #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 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+0x1b1/0x540 kernel/locking/lockdep.c:5719 __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+0x9c5/0x1c80 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0xb4/0xe0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x119/0x280 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+0x196/0x220 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd5/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 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-executor237/5105: #0: ffff88802ade4258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1671 [inline] #0: ffff88802ade4258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_ioctl+0xa7/0xe0 net/bluetooth/rfcomm/sock.c:872 #1: ffffffff8f5912a8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] #1: ffffffff8f5912a8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x8e4/0x1c80 net/bluetooth/rfcomm/tty.c:587 stack backtrace: CPU: 1 PID: 5105 Comm: syz-executor237 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Call Trace: __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+0x1b1/0x540 kernel/locking/lockdep.c:5719 __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+0x9c5/0x1c80 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0xb4/0xe0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x119/0x280 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+0x196/0x220 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd5/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f6140612d49 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 19 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:00007ffe334cb378 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f6140612d49 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000005 RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000555500000000 R10: 0000555500000000 R11: 0000000000000246 R12: 00007ffe334cb3c0 R13: 00007ffe334cb3d0 R14: 000000000002da18 R15: 00007ffe334cb390