====================================================== WARNING: possible circular locking dependency detected 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted ------------------------------------------------------ syz-executor370/5115 is trying to acquire lock: ffff888075114258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1671 [inline] ffff888075114258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x5b/0x310 net/bluetooth/rfcomm/sock.c:73 but task is already holding lock: ffff8880750d9d28 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&d->lock){+.+.}-{3:3}: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __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:905 rfcomm_sock_release+0x59/0x120 net/bluetooth/rfcomm/sock.c:926 __sock_release net/socket.c:659 [inline] sock_close+0xbe/0x240 net/socket.c:1421 __fput+0x42b/0x8a0 fs/file_table.c:422 task_work_run+0x251/0x310 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa1b/0x27e0 kernel/exit.c:878 do_group_exit+0x207/0x2c0 kernel/exit.c:1027 get_signal+0x176e/0x1850 kernel/signal.c:2907 arch_do_signal_or_restart+0x96/0x860 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+0xc9/0x360 kernel/entry/common.c:212 do_syscall_64+0x10a/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6d/0x75 -> #2 (rfcomm_mutex){+.+.}-{3:3}: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __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+0xb31/0x21b0 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0x86/0xd0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x15a/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl+0xfe/0x170 fs/ioctl.c:890 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 -> #1 (rfcomm_ioctl_mutex){+.+.}-{3:3}: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __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+0x237/0x21b0 net/bluetooth/rfcomm/tty.c:587 rfcomm_sock_ioctl+0x86/0xd0 net/bluetooth/rfcomm/sock.c:873 sock_do_ioctl+0x15a/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl+0xfe/0x170 fs/ioctl.c:890 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 lock_sock_nested+0x48/0x100 net/core/sock.c:3535 lock_sock include/net/sock.h:1671 [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:905 rfcomm_sock_release+0x59/0x120 net/bluetooth/rfcomm/sock.c:926 __sock_release net/socket.c:659 [inline] sock_close+0xbe/0x240 net/socket.c:1421 __fput+0x42b/0x8a0 fs/file_table.c:422 task_work_run+0x251/0x310 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa1b/0x27e0 kernel/exit.c:878 do_group_exit+0x207/0x2c0 kernel/exit.c:1027 get_signal+0x176e/0x1850 kernel/signal.c:2907 arch_do_signal_or_restart+0x96/0x860 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+0xc9/0x360 kernel/entry/common.c:212 do_syscall_64+0x10a/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6d/0x75 other info that might help us debug this: Chain exists of: sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM --> rfcomm_mutex --> &d->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&d->lock); lock(rfcomm_mutex); lock(&d->lock); lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); *** DEADLOCK *** 3 locks held by syz-executor370/5115: #0: ffff888077a66210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline] #0: ffff888077a66210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline] #0: ffff888077a66210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1421 #1: ffffffff8f518728 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x3b/0x190 net/bluetooth/rfcomm/core.c:511 #2: ffff8880750d9d28 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491 stack backtrace: CPU: 0 PID: 5115 Comm: syz-executor370 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #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+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 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+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 lock_sock_nested+0x48/0x100 net/core/sock.c:3535 lock_sock include/net/sock.h:1671 [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:905 rfcomm_sock_release+0x59/0x120 net/bluetooth/rfcomm/sock.c:926 __sock_release net/socket.c:659 [inline] sock_close+0xbe/0x240 net/socket.c:1421 __fput+0x42b/0x8a0 fs/file_table.c:422 task_work_run+0x251/0x310 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa1b/0x27e0 kernel/exit.c:878 do_group_exit+0x207/0x2c0 kernel/exit.c:1027 get_signal+0x176e/0x1850 kernel/signal.c:2907 arch_do_signal_or_restart+0x96/0x860 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+0xc9/0x360 kernel/entry/common.c:212 do_syscall_64+0x10a/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7ff4b6deff79 Code: Unable to access opcode bytes at 0x7ff4b6deff4f. RSP: 002b:00007ffe92759a58 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffffc RBX: 0000000000000000 RCX: 00007ff4b6deff79 RDX: 000000000000000a RSI: 0000000020000040 RDI: 0000000000000004 RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000055556fb1a370 R13: 0000000000000001 R14: 00007ffe92759ad0 R15: 00007ffe92759ac0