====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc2-syzkaller-00058-g75b607fab38d #0 Not tainted ------------------------------------------------------ syz.5.3206/22431 is trying to acquire lock: ffffffff8fe5fdc8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_exists+0xa6/0x380 net/bluetooth/rfcomm/core.c:546 but task is already holding lock: ffffffff8fe63928 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] ffffffff8fe63928 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x237/0x2220 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}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] rfcomm_dev_ioctl+0x237/0x2220 net/bluetooth/rfcomm/tty.c:584 rfcomm_sock_ioctl+0x86/0xd0 net/bluetooth/rfcomm/sock.c:869 sock_do_ioctl+0x15a/0x460 net/socket.c:1227 sock_ioctl+0x626/0x8e0 net/socket.c:1346 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 lock_sock_nested+0x48/0x100 net/core/sock.c:3611 lock_sock include/net/sock.h:1609 [inline] rfcomm_sk_state_change+0x5b/0x310 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x271/0x6a0 net/bluetooth/rfcomm/core.c:493 rfcomm_dlc_close+0xf1/0x190 net/bluetooth/rfcomm/core.c:524 __rfcomm_sock_close+0x121/0x250 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xb8/0x240 net/bluetooth/rfcomm/sock.c:901 rfcomm_sock_release+0x59/0x120 net/bluetooth/rfcomm/sock.c:922 __sock_release net/socket.c:658 [inline] sock_close+0xbe/0x240 net/socket.c:1426 __fput+0x241/0x880 fs/file_table.c:431 task_work_run+0x251/0x310 kernel/task_work.c:228 get_signal+0x15e8/0x1740 kernel/signal.c:2690 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&d->lock){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 __rfcomm_dlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491 rfcomm_dlc_close+0xf1/0x190 net/bluetooth/rfcomm/core.c:524 __rfcomm_sock_close+0x121/0x250 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xb8/0x240 net/bluetooth/rfcomm/sock.c:901 rfcomm_sock_release+0x59/0x120 net/bluetooth/rfcomm/sock.c:922 __sock_release net/socket.c:658 [inline] sock_close+0xbe/0x240 net/socket.c:1426 __fput+0x241/0x880 fs/file_table.c:431 task_work_run+0x251/0x310 kernel/task_work.c:228 get_signal+0x15e8/0x1740 kernel/signal.c:2690 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #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+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 rfcomm_dlc_exists+0xa6/0x380 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+0xb53/0x2220 net/bluetooth/rfcomm/tty.c:584 rfcomm_sock_ioctl+0x86/0xd0 net/bluetooth/rfcomm/sock.c:869 sock_do_ioctl+0x15a/0x460 net/socket.c:1227 sock_ioctl+0x626/0x8e0 net/socket.c:1346 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f 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.5.3206/22431: #0: ffff8881467c4258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline] #0: ffff8881467c4258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_ioctl+0x78/0xd0 net/bluetooth/rfcomm/sock.c:868 #1: ffffffff8fe63928 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:484 [inline] #1: ffffffff8fe63928 (rfcomm_ioctl_mutex){+.+.}-{3:3}, at: rfcomm_dev_ioctl+0x237/0x2220 net/bluetooth/rfcomm/tty.c:584 stack backtrace: CPU: 1 UID: 0 PID: 22431 Comm: syz.5.3206 Not tainted 6.12.0-rc2-syzkaller-00058-g75b607fab38d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 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+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 rfcomm_dlc_exists+0xa6/0x380 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+0xb53/0x2220 net/bluetooth/rfcomm/tty.c:584 rfcomm_sock_ioctl+0x86/0xd0 net/bluetooth/rfcomm/sock.c:869 sock_do_ioctl+0x15a/0x460 net/socket.c:1227 sock_ioctl+0x626/0x8e0 net/socket.c:1346 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb55f17dff9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb55fec1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb55f336130 RCX: 00007fb55f17dff9 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000008 RBP: 00007fb55f1f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb55f336130 R15: 00007ffdc9459758