------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint: rfcomm_dlc_timeout+0x0/0xc0 net/bluetooth/rfcomm/core.c:2105
WARNING: CPU: 1 PID: 20017 at lib/debugobjects.c:329 debug_print_object+0x16a/0x210 lib/debugobjects.c:326
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 20017 Comm: syz-executor2 Not tainted 4.19.0-rc4+ #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 panic+0x238/0x4e7 kernel/panic.c:184
 __warn.cold.8+0x163/0x1ba kernel/panic.c:536
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
kobject: 'loop5' (00000000a8a99c69): kobject_uevent_env
kobject: 'loop5' (00000000a8a99c69): fill_kobj_path: path = '/devices/virtual/block/loop5'
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:993
RIP: 0010:debug_print_object+0x16a/0x210 lib/debugobjects.c:326
Code: 44 88 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 92 00 00 00 48 8b 14 dd 20 b0 44 88 4c 89 fe 48 c7 c7 60 a4 44 88 e8 f6 39 b8 fd <0f> 0b 83 05 59 ef a0 06 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f
kobject: 'loop1' (00000000983124c3): kobject_uevent_env
RSP: 0018:ffff880193a9f638 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffc90005d03000
RDX: 000000000003f684 RSI: ffffffff81650d15 RDI: 0000000000000005
RBP: ffff880193a9f678 R08: ffff8801892cc380 R09: ffffed003b5e3ee2
R10: ffffed003b5e3ee2 R11: ffff8801daf1f717 R12: 0000000000000001
R13: ffffffff895ad0c0 R14: ffffffff816bbab0 R15: ffffffff8844a900
kobject: 'loop1' (00000000983124c3): fill_kobj_path: path = '/devices/virtual/block/loop1'
 __debug_check_no_obj_freed lib/debugobjects.c:786 [inline]
 debug_check_no_obj_freed+0x3ae/0x58d lib/debugobjects.c:818
kobject: 'loop0' (000000001068c3e7): kobject_uevent_env
 kfree+0xbd/0x230 mm/slab.c:3812
 rfcomm_dlc_free+0x2d/0x50 net/bluetooth/rfcomm/core.c:328
 rfcomm_dlc_put include/net/bluetooth/rfcomm.h:258 [inline]
 __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:417 [inline]
 rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline]
 rfcomm_dev_ioctl+0x206e/0x24a0 net/bluetooth/rfcomm/tty.c:588
kobject: 'loop0' (000000001068c3e7): fill_kobj_path: path = '/devices/virtual/block/loop0'
 rfcomm_sock_ioctl+0xbf/0xf0 net/bluetooth/rfcomm/sock.c:902
 sock_do_ioctl+0xeb/0x420 net/socket.c:950
 sock_ioctl+0x313/0x690 net/socket.c:1074
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457679
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fad203aec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fad203af6d4 RCX: 0000000000457679
RDX: 00000000200000c0 RSI: 00000000400452c8 RDI: 0000000000000003
RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cfe68 R14: 00000000004bff86 R15: 0000000000000001

======================================================
WARNING: possible circular locking dependency detected
4.19.0-rc4+ #28 Not tainted
------------------------------------------------------
syz-executor2/20017 is trying to acquire lock:
00000000d067f394 ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
00000000f7c5961a (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:777 [inline]
00000000f7c5961a (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0x17a/0x58d lib/debugobjects.c:818

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&obj_hash[i].lock){-.-.}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       __debug_object_init+0x127/0x1290 lib/debugobjects.c:384
       debug_object_init+0x16/0x20 lib/debugobjects.c:432
       debug_hrtimer_init kernel/time/hrtimer.c:410 [inline]
       debug_init kernel/time/hrtimer.c:458 [inline]
       hrtimer_init+0x97/0x490 kernel/time/hrtimer.c:1308
       init_dl_task_timer+0x1b/0x50 kernel/sched/deadline.c:1057
       __sched_fork+0x2ae/0x590 kernel/sched/core.c:2160
       init_idle+0x75/0x7a0 kernel/sched/core.c:5377
       sched_init+0xb33/0xc02 kernel/sched/core.c:6060
       start_kernel+0x47d/0x92f init/main.c:602
       x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
       x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
       secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

-> #2 (&rq->lock){-.-.}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144
       rq_lock kernel/sched/sched.h:1821 [inline]
       task_fork_fair+0xb0/0x6d0 kernel/sched/fair.c:9581
       sched_fork+0x443/0xba0 kernel/sched/core.c:2353
       copy_process+0x2586/0x8780 kernel/fork.c:1839
       _do_fork+0x1cb/0x11d0 kernel/fork.c:2166
       kernel_thread+0x34/0x40 kernel/fork.c:2225
       rest_init+0x22/0xe5 init/main.c:408
       start_kernel+0x8f4/0x92f init/main.c:739
       x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
       x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
       secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

-> #1 (&p->pi_lock){-.-.}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       try_to_wake_up+0xd2/0x12f0 kernel/sched/core.c:1960
       wake_up_process+0x10/0x20 kernel/sched/core.c:2123
       __up.isra.1+0x1c0/0x2a0 kernel/locking/semaphore.c:262
       up+0x13c/0x1c0 kernel/locking/semaphore.c:187
       __up_console_sem+0xbe/0x1b0 kernel/printk/printk.c:244
       console_unlock+0x814/0x1160 kernel/printk/printk.c:2427
       vprintk_emit+0x33d/0x930 kernel/printk/printk.c:1922
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1963
       vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
       printk+0xa7/0xcf kernel/printk/printk.c:1996
       load_umh+0x51/0xbd net/bpfilter/bpfilter_kern.c:98
       do_one_initcall+0x145/0x957 init/main.c:885
       do_initcall_level init/main.c:953 [inline]
       do_initcalls init/main.c:961 [inline]
       do_basic_setup init/main.c:979 [inline]
       kernel_init_freeable+0x4bb/0x5ae init/main.c:1144
       kernel_init+0x11/0x1b2 init/main.c:1063
       ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413

-> #0 ((console_sem).lock){-.-.}:
       lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3900
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
       __down_trylock_console_sem+0xae/0x200 kernel/printk/printk.c:227
       console_trylock+0x15/0xa0 kernel/printk/printk.c:2245
       console_trylock_spinning kernel/printk/printk.c:1649 [inline]
       vprintk_emit+0x322/0x930 kernel/printk/printk.c:1921
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1963
       vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
       printk+0xa7/0xcf kernel/printk/printk.c:1996
       __warn_printk+0x8c/0xe0 kernel/panic.c:590
       debug_print_object+0x16a/0x210 lib/debugobjects.c:326
       __debug_check_no_obj_freed lib/debugobjects.c:786 [inline]
       debug_check_no_obj_freed+0x3ae/0x58d lib/debugobjects.c:818
       kfree+0xbd/0x230 mm/slab.c:3812
       rfcomm_dlc_free+0x2d/0x50 net/bluetooth/rfcomm/core.c:328
       rfcomm_dlc_put include/net/bluetooth/rfcomm.h:258 [inline]
       __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:417 [inline]
       rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline]
       rfcomm_dev_ioctl+0x206e/0x24a0 net/bluetooth/rfcomm/tty.c:588
       rfcomm_sock_ioctl+0xbf/0xf0 net/bluetooth/rfcomm/sock.c:902
       sock_do_ioctl+0xeb/0x420 net/socket.c:950
       sock_ioctl+0x313/0x690 net/socket.c:1074
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:501 [inline]
       do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
       ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
       __do_sys_ioctl fs/ioctl.c:709 [inline]
       __se_sys_ioctl fs/ioctl.c:707 [inline]
       __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
       do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Chain exists of:
  (console_sem).lock --> &rq->lock --> &obj_hash[i].lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&obj_hash[i].lock);
                               lock(&rq->lock);
                               lock(&obj_hash[i].lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

3 locks held by syz-executor2/20017:
 #0: 000000007953c49a (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}, at: lock_sock include/net/sock.h:1491 [inline]
 #0: 000000007953c49a (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}, at: rfcomm_sock_ioctl+0xb1/0xf0 net/bluetooth/rfcomm/sock.c:901
 #1: 00000000b0a869be (rfcomm_ioctl_mutex){+.+.}, at: rfcomm_create_dev net/bluetooth/rfcomm/tty.c:485 [inline]
 #1: 00000000b0a869be (rfcomm_ioctl_mutex){+.+.}, at: rfcomm_dev_ioctl+0x12e/0x24a0 net/bluetooth/rfcomm/tty.c:588
 #2: 00000000f7c5961a (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:777 [inline]
 #2: 00000000f7c5961a (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0x17a/0x58d lib/debugobjects.c:818

stack backtrace:
CPU: 1 PID: 20017 Comm: syz-executor2 Not tainted 4.19.0-rc4+ #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 print_circular_bug.isra.33.cold.54+0x1bd/0x27d kernel/locking/lockdep.c:1221
 check_prev_add kernel/locking/lockdep.c:1861 [inline]
 check_prevs_add kernel/locking/lockdep.c:1974 [inline]
 validate_chain kernel/locking/lockdep.c:2415 [inline]
 __lock_acquire+0x33e4/0x4ec0 kernel/locking/lockdep.c:3411
 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3900
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
 __down_trylock_console_sem+0xae/0x200 kernel/printk/printk.c:227
 console_trylock+0x15/0xa0 kernel/printk/printk.c:2245
 console_trylock_spinning kernel/printk/printk.c:1649 [inline]
 vprintk_emit+0x322/0x930 kernel/printk/printk.c:1921
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1963
 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
 printk+0xa7/0xcf kernel/printk/printk.c:1996
 __warn_printk+0x8c/0xe0 kernel/panic.c:590
 debug_print_object+0x16a/0x210 lib/debugobjects.c:326
 __debug_check_no_obj_freed lib/debugobjects.c:786 [inline]
 debug_check_no_obj_freed+0x3ae/0x58d lib/debugobjects.c:818
 kfree+0xbd/0x230 mm/slab.c:3812
 rfcomm_dlc_free+0x2d/0x50 net/bluetooth/rfcomm/core.c:328
 rfcomm_dlc_put include/net/bluetooth/rfcomm.h:258 [inline]
 __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:417 [inline]
 rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline]
 rfcomm_dev_ioctl+0x206e/0x24a0 net/bluetooth/rfcomm/tty.c:588
 rfcomm_sock_ioctl+0xbf/0xf0 net/bluetooth/rfcomm/sock.c:902
 sock_do_ioctl+0xeb/0x420 net/socket.c:950
 sock_ioctl+0x313/0x690 net/socket.c:1074
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457679
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fad203aec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fad203af6d4 RCX: 0000000000457679
RDX: 00000000200000c0 RSI: 00000000400452c8 RDI: 0000000000000003
RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cfe68 R14: 00000000004bff86 R15: 0000000000000001
Kernel Offset: disabled
Rebooting in 86400 seconds..