====================================================== WARNING: possible circular locking dependency detected 5.15.158-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/18684 is trying to acquire lock: ffffffff8db4fc68 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_exists+0xa2/0x370 net/bluetooth/rfcomm/core.c:542 but task is already holding lock: ffffffff8db53648 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline] ffffffff8db53648 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x233/0x2180 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}: 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+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}: 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 __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+0x147/0x1a0 net/socket.c:2288 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&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 __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+0x147/0x1a0 net/socket.c:2288 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #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+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 __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+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 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.4/18684: #0: ffff888073a24120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1668 [inline] #0: ffff888073a24120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_ioctl+0x74/0xc0 net/bluetooth/rfcomm/sock.c:879 #1: ffffffff8db53648 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline] #1: ffffffff8db53648 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x233/0x2180 net/bluetooth/rfcomm/tty.c:588 stack backtrace: CPU: 0 PID: 18684 Comm: syz-executor.4 Not tainted 5.15.158-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 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 __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+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f8b0dde0ea9 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:00007f8b0c3320c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f8b0df0f050 RCX: 00007f8b0dde0ea9 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000005 RBP: 00007f8b0de2d4a4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f8b0df0f050 R15: 00007ffd2efcbb98