====================================================== WARNING: possible circular locking dependency detected 5.15.167-syzkaller #0 Not tainted ------------------------------------------------------ syz.2.1814/9314 is trying to acquire lock: ffff800016d559e8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_exists+0xb0/0x32c net/bluetooth/rfcomm/core.c:542 but task is already holding lock: ffff800016d59348 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline] ffff800016d59348 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x258/0x2434 net/bluetooth/rfcomm/tty.c:588 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+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline] rfcomm_dev_ioctl+0x258/0x2434 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x98/0xf0 net/bluetooth/rfcomm/sock.c:880 sock_do_ioctl+0x134/0x2dc net/socket.c:1140 sock_ioctl+0x4f0/0x8ac net/socket.c:1257 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}: lock_sock_nested+0xec/0x1ec net/core/sock.c:3250 lock_sock include/net/sock.h:1676 [inline] rfcomm_sk_state_change+0x60/0x2c8 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x23c/0x634 net/bluetooth/rfcomm/core.c:489 rfcomm_dlc_close+0x100/0x194 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0x138/0x258 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xa8/0x214 net/bluetooth/rfcomm/sock.c:912 __sys_shutdown_sock net/socket.c:2270 [inline] __sys_shutdown net/socket.c:2282 [inline] __do_sys_shutdown net/socket.c:2290 [inline] __se_sys_shutdown net/socket.c:2288 [inline] __arm64_sys_shutdown+0x174/0x1d8 net/socket.c:2288 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #1 (&d->lock){+.+.}-{3:3}: __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 __rfcomm_dlc_close+0x200/0x634 net/bluetooth/rfcomm/core.c:487 rfcomm_dlc_close+0x100/0x194 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0x138/0x258 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xa8/0x214 net/bluetooth/rfcomm/sock.c:912 __sys_shutdown_sock net/socket.c:2270 [inline] __sys_shutdown net/socket.c:2282 [inline] __do_sys_shutdown net/socket.c:2290 [inline] __se_sys_shutdown net/socket.c:2288 [inline] __arm64_sys_shutdown+0x174/0x1d8 net/socket.c:2288 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #0 (rfcomm_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 rfcomm_dlc_exists+0xb0/0x32c 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+0x938/0x2434 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x98/0xf0 net/bluetooth/rfcomm/sock.c:880 sock_do_ioctl+0x134/0x2dc net/socket.c:1140 sock_ioctl+0x4f0/0x8ac net/socket.c:1257 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 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.2.1814/9314: #0: ffff0000cd7d1120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1676 [inline] #0: ffff0000cd7d1120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_ioctl+0x88/0xf0 net/bluetooth/rfcomm/sock.c:879 #1: ffff800016d59348 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline] #1: ffff800016d59348 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x258/0x2434 net/bluetooth/rfcomm/tty.c:588 stack backtrace: CPU: 1 PID: 9314 Comm: syz.2.1814 Not tainted 5.15.167-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011 check_noncircular+0x2cc/0x378 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 kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743 rfcomm_dlc_exists+0xb0/0x32c 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+0x938/0x2434 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x98/0xf0 net/bluetooth/rfcomm/sock.c:880 sock_do_ioctl+0x134/0x2dc net/socket.c:1140 sock_ioctl+0x4f0/0x8ac net/socket.c:1257 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584