====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc1-syzkaller-g80cb3fb61135 #0 Not tainted ------------------------------------------------------ syz.1.182/7543 is trying to acquire lock: ffff8000928827e8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_exists+0xb0/0x32c net/bluetooth/rfcomm/core.c:546 but task is already holding lock: ffff8000928861a8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] ffff8000928861a8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x25c/0x231c net/bluetooth/rfcomm/tty.c:584 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+0x190/0x21a0 kernel/locking/mutex.c:608 __mutex_lock kernel/locking/mutex.c:752 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:804 rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] rfcomm_dev_ioctl+0x25c/0x231c net/bluetooth/rfcomm/tty.c:584 rfcomm_sock_ioctl+0x98/0xf0 net/bluetooth/rfcomm/sock.c:869 sock_do_ioctl+0x134/0x2d0 net/socket.c:1227 sock_ioctl+0x4ec/0x838 net/socket.c:1346 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:732 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:750 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 -> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}: lock_sock_nested+0x5c/0x11c net/core/sock.c:3611 lock_sock include/net/sock.h:1609 [inline] rfcomm_sk_state_change+0x60/0x2c8 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x234/0x608 net/bluetooth/rfcomm/core.c:493 rfcomm_dlc_close+0x100/0x194 net/bluetooth/rfcomm/core.c:524 __rfcomm_sock_close+0x138/0x258 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xa8/0x214 net/bluetooth/rfcomm/sock.c:901 rfcomm_sock_release+0x58/0x114 net/bluetooth/rfcomm/sock.c:922 __sock_release net/socket.c:658 [inline] sock_close+0xa4/0x1e8 net/socket.c:1426 __fput+0x1bc/0x75c fs/file_table.c:431 delayed_fput+0x78/0xac fs/file_table.c:454 process_one_work+0x7bc/0x1600 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x97c/0xeec kernel/workqueue.c:3391 kthread+0x288/0x310 kernel/kthread.c:389 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #1 (&d->lock){+.+.}-{3:3}: __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:608 __mutex_lock kernel/locking/mutex.c:752 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:804 __rfcomm_dlc_close+0x1f8/0x608 net/bluetooth/rfcomm/core.c:491 rfcomm_dlc_close+0x100/0x194 net/bluetooth/rfcomm/core.c:524 __rfcomm_sock_close+0x138/0x258 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xa8/0x214 net/bluetooth/rfcomm/sock.c:901 rfcomm_sock_release+0x58/0x114 net/bluetooth/rfcomm/sock.c:922 __sock_release net/socket.c:658 [inline] sock_close+0xa4/0x1e8 net/socket.c:1426 __fput+0x1bc/0x75c fs/file_table.c:431 delayed_fput+0x78/0xac fs/file_table.c:454 process_one_work+0x7bc/0x1600 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x97c/0xeec kernel/workqueue.c:3391 kthread+0x288/0x310 kernel/kthread.c:389 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #0 (rfcomm_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x33f8/0x77c8 kernel/locking/lockdep.c:5202 lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5825 __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:608 __mutex_lock kernel/locking/mutex.c:752 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:804 rfcomm_dlc_exists+0xb0/0x32c 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+0xd64/0x231c net/bluetooth/rfcomm/tty.c:584 rfcomm_sock_ioctl+0x98/0xf0 net/bluetooth/rfcomm/sock.c:869 sock_do_ioctl+0x134/0x2d0 net/socket.c:1227 sock_ioctl+0x4ec/0x838 net/socket.c:1346 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:732 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:750 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 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.1.182/7543: #0: ffff0000edeb3258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline] #0: ffff0000edeb3258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_ioctl+0x88/0xf0 net/bluetooth/rfcomm/sock.c:868 #1: ffff8000928861a8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] #1: ffff8000928861a8 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x25c/0x231c net/bluetooth/rfcomm/tty.c:584 stack backtrace: CPU: 1 UID: 0 PID: 7543 Comm: syz.1.182 Not tainted 6.12.0-rc1-syzkaller-g80cb3fb61135 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:319 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:326 __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x154/0x1c0 kernel/locking/lockdep.c:2074 check_noncircular+0x310/0x404 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x33f8/0x77c8 kernel/locking/lockdep.c:5202 lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5825 __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:608 __mutex_lock kernel/locking/mutex.c:752 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:804 rfcomm_dlc_exists+0xb0/0x32c 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+0xd64/0x231c net/bluetooth/rfcomm/tty.c:584 rfcomm_sock_ioctl+0x98/0xf0 net/bluetooth/rfcomm/sock.c:869 sock_do_ioctl+0x134/0x2d0 net/socket.c:1227 sock_ioctl+0x4ec/0x838 net/socket.c:1346 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:732 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:750 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598