------------[ cut here ]------------ ODEBUG: free active (active state 1) object type: rcu_head hint: (null) WARNING: CPU: 0 PID: 5641 at lib/debugobjects.c:329 debug_print_object+0x16a/0x210 lib/debugobjects.c:326 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 5641 Comm: syz-executor3 Not tainted 4.19.0-rc7-next-20181015+ #94 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+0x244/0x39d lib/dump_stack.c:113 panic+0x2ad/0x55c kernel/panic.c:188 __warn.cold.8+0x20/0x45 kernel/panic.c:540 report_bug+0x254/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969 RIP: 0010:debug_print_object+0x16a/0x210 lib/debugobjects.c:326 Code: 41 88 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 92 00 00 00 48 8b 14 dd 80 08 41 88 4c 89 fe 48 c7 c7 20 fe 40 88 e8 36 c3 b3 fd <0f> 0b 83 05 b9 ff 5e 06 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffff8801c6887440 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff81647515 RDI: 0000000000000005 RBP: ffff8801c6887480 R08: ffff8801c687e5c0 R09: ffffed003b5c3eda R10: ffffed003b5c3eda R11: ffff8801dae1f6d7 R12: 0000000000000001 R13: ffffffff8939a4e0 R14: 0000000000000000 R15: ffffffff884102c0 __debug_check_no_obj_freed lib/debugobjects.c:786 [inline] debug_check_no_obj_freed+0x3ae/0x58d lib/debugobjects.c:818 kmem_cache_free+0x202/0x290 mm/slab.c:3759 free_task_struct kernel/fork.c:163 [inline] free_task+0x16e/0x1f0 kernel/fork.c:457 __put_task_struct+0x2e6/0x620 kernel/fork.c:730 put_task_struct include/linux/sched/task.h:96 [inline] finish_task_switch+0x66b/0x920 kernel/sched/core.c:2715 context_switch kernel/sched/core.c:2834 [inline] __schedule+0x8d7/0x21d0 kernel/sched/core.c:3480 schedule+0xfe/0x460 kernel/sched/core.c:3524 freezable_schedule include/linux/freezer.h:172 [inline] do_nanosleep+0x21e/0x750 kernel/time/hrtimer.c:1688 kobject: 'loop5' (000000003e7142d7): kobject_uevent_env kobject: 'loop5' (000000003e7142d7): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop4' (00000000f653000e): kobject_uevent_env hrtimer_nanosleep+0x2d4/0x620 kernel/time/hrtimer.c:1742 kobject: 'loop4' (00000000f653000e): fill_kobj_path: path = '/devices/virtual/block/loop4' kobject: 'loop5' (000000003e7142d7): kobject_uevent_env __do_sys_nanosleep kernel/time/hrtimer.c:1776 [inline] __se_sys_nanosleep kernel/time/hrtimer.c:1763 [inline] __x64_sys_nanosleep+0x1e7/0x280 kernel/time/hrtimer.c:1763 kobject: 'loop5' (000000003e7142d7): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop4' (00000000f653000e): kobject_uevent_env do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 kobject: 'loop4' (00000000f653000e): fill_kobj_path: path = '/devices/virtual/block/loop4' kobject: 'loop5' (000000003e7142d7): kobject_uevent_env kobject: 'loop5' (000000003e7142d7): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop4' (00000000f653000e): kobject_uevent_env kobject: 'loop4' (00000000f653000e): fill_kobj_path: path = '/devices/virtual/block/loop4' entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x483060 kobject: 'loop5' (000000003e7142d7): kobject_uevent_env Code: 00 00 48 c7 c0 d4 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb be 66 0f 1f 44 00 00 83 3d 11 34 5c 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 d4 f8 f8 ff c3 48 83 ec 08 e8 ba 70 fd ff RSP: 002b:00007ffc7e472c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000023 kobject: 'loop5' (000000003e7142d7): fill_kobj_path: path = '/devices/virtual/block/loop5' RAX: ffffffffffffffda RBX: 00000000000b0592 RCX: 0000000000483060 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffc7e472c70 RBP: 0000000000001163 R08: 0000000000000001 R09: 000000000242a940 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000b057e R14: 0000000000000614 R15: 0000000000000003 ====================================================== WARNING: possible circular locking dependency detected 4.19.0-rc7-next-20181015+ #94 Not tainted ------------------------------------------------------ syz-executor3/5641 is trying to acquire lock: 0000000036958e7b ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 but task is already holding lock: 000000006a5aa187 (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:777 [inline] 000000006a5aa187 (&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:2166 init_idle+0x75/0x740 kernel/sched/core.c:5382 sched_init+0xb33/0xc02 kernel/sched/core.c:6065 start_kernel+0x4be/0xa2b init/main.c:608 x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:472 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #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:1127 [inline] task_fork_fair+0xb0/0x6d0 kernel/sched/fair.c:9768 sched_fork+0x443/0xba0 kernel/sched/core.c:2359 copy_process+0x2585/0x8770 kernel/fork.c:1887 _do_fork+0x1cb/0x11c0 kernel/fork.c:2216 kernel_thread+0x34/0x40 kernel/fork.c:2275 rest_init+0x28/0x372 init/main.c:409 arch_call_rest_init+0xe/0x1b start_kernel+0x9f0/0xa2b init/main.c:745 x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:472 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #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+0xd2/0x12e0 kernel/sched/core.c:1965 wake_up_process+0x10/0x20 kernel/sched/core.c:2129 __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:236 console_unlock+0x80c/0x1190 kernel/printk/printk.c:2432 vprintk_emit+0x391/0x990 kernel/printk/printk.c:1922 vprintk_default+0x28/0x30 kernel/printk/printk.c:1964 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:1997 check_stack_usage kernel/exit.c:755 [inline] do_exit.cold.18+0x57/0x16f kernel/exit.c:916 do_group_exit+0x177/0x440 kernel/exit.c:970 __do_sys_exit_group kernel/exit.c:981 [inline] __se_sys_exit_group kernel/exit.c:979 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 ((console_sem).lock){-.-.}: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3845 __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/0x1f0 kernel/printk/printk.c:219 console_trylock+0x15/0xa0 kernel/printk/printk.c:2247 console_trylock_spinning kernel/printk/printk.c:1653 [inline] vprintk_emit+0x372/0x990 kernel/printk/printk.c:1921 vprintk_default+0x28/0x30 kernel/printk/printk.c:1964 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:1997 __warn_printk+0x8c/0xe0 kernel/panic.c:594 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 kmem_cache_free+0x202/0x290 mm/slab.c:3759 free_task_struct kernel/fork.c:163 [inline] free_task+0x16e/0x1f0 kernel/fork.c:457 __put_task_struct+0x2e6/0x620 kernel/fork.c:730 put_task_struct include/linux/sched/task.h:96 [inline] finish_task_switch+0x66b/0x920 kernel/sched/core.c:2715 context_switch kernel/sched/core.c:2834 [inline] __schedule+0x8d7/0x21d0 kernel/sched/core.c:3480 schedule+0xfe/0x460 kernel/sched/core.c:3524 freezable_schedule include/linux/freezer.h:172 [inline] do_nanosleep+0x21e/0x750 kernel/time/hrtimer.c:1688 hrtimer_nanosleep+0x2d4/0x620 kernel/time/hrtimer.c:1742 __do_sys_nanosleep kernel/time/hrtimer.c:1776 [inline] __se_sys_nanosleep kernel/time/hrtimer.c:1763 [inline] __x64_sys_nanosleep+0x1e7/0x280 kernel/time/hrtimer.c:1763 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 *** 1 lock held by syz-executor3/5641: #0: 000000006a5aa187 (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:777 [inline] #0: 000000006a5aa187 (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0x17a/0x58d lib/debugobjects.c:818 stack backtrace: CPU: 0 PID: 5641 Comm: syz-executor3 Not tainted 4.19.0-rc7-next-20181015+ #94 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+0x244/0x39d lib/dump_stack.c:113 print_circular_bug.isra.35.cold.54+0x1bd/0x27d kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1864 [inline] check_prevs_add kernel/locking/lockdep.c:1977 [inline] validate_chain kernel/locking/lockdep.c:2348 [inline] __lock_acquire+0x3399/0x4c20 kernel/locking/lockdep.c:3342 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3845 __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/0x1f0 kernel/printk/printk.c:219 console_trylock+0x15/0xa0 kernel/printk/printk.c:2247 console_trylock_spinning kernel/printk/printk.c:1653 [inline] vprintk_emit+0x372/0x990 kernel/printk/printk.c:1921 vprintk_default+0x28/0x30 kernel/printk/printk.c:1964 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:1997 __warn_printk+0x8c/0xe0 kernel/panic.c:594 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 kmem_cache_free+0x202/0x290 mm/slab.c:3759 free_task_struct kernel/fork.c:163 [inline] free_task+0x16e/0x1f0 kernel/fork.c:457 __put_task_struct+0x2e6/0x620 kernel/fork.c:730 put_task_struct include/linux/sched/task.h:96 [inline] finish_task_switch+0x66b/0x920 kernel/sched/core.c:2715 context_switch kernel/sched/core.c:2834 [inline] __schedule+0x8d7/0x21d0 kernel/sched/core.c:3480 schedule+0xfe/0x460 kernel/sched/core.c:3524 freezable_schedule include/linux/freezer.h:172 [inline] do_nanosleep+0x21e/0x750 kernel/time/hrtimer.c:1688 hrtimer_nanosleep+0x2d4/0x620 kernel/time/hrtimer.c:1742 __do_sys_nanosleep kernel/time/hrtimer.c:1776 [inline] __se_sys_nanosleep kernel/time/hrtimer.c:1763 [inline] __x64_sys_nanosleep+0x1e7/0x280 kernel/time/hrtimer.c:1763 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x483060 Code: 00 00 48 c7 c0 d4 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb be 66 0f 1f 44 00 00 83 3d 11 34 5c 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 d4 f8 f8 ff c3 48 83 ec 08 e8 ba 70 fd ff RSP: 002b:00007ffc7e472c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000023 RAX: ffffffffffffffda RBX: 00000000000b0592 RCX: 0000000000483060 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffc7e472c70 RBP: 0000000000001163 R08: 0000000000000001 R09: 000000 Lost 2 message(s)! Kernel Offset: disabled Rebooting in 86400 seconds..