------------[ cut here ]------------ ODEBUG: free active (active state 1) object type: rcu_head hint: (null) WARNING: CPU: 0 PID: 7594 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: 7594 Comm: syz-executor2 Not tainted 4.19.0-rc7-next-20181012+ #93 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+0x244/0x3ab 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+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 20 07 41 88 4c 89 fe 48 c7 c7 c0 fc 40 88 e8 96 e0 b3 fd <0f> 0b 83 05 c9 dd 5e 06 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffff8801815cee90 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffc9000628c000 RDX: 000000000003f203 RSI: ffffffff8164bc15 RDI: 0000000000000005 RBP: ffff8801815ceed0 R08: ffff8801815c4300 R09: ffffed003b5c3eda R10: ffffed003b5c3eda R11: ffff8801dae1f6d7 R12: 0000000000000001 R13: ffffffff8939a4e0 R14: 0000000000000000 R15: ffffffff88410160 __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+0x66c/0x900 kernel/sched/core.c:2715 context_switch kernel/sched/core.c:2834 [inline] __schedule+0x8d7/0x21d0 kernel/sched/core.c:3480 preempt_schedule_common+0x1f/0xd0 kernel/sched/core.c:3604 preempt_schedule+0x4d/0x60 kernel/sched/core.c:3630 ___preempt_schedule+0x16/0x18 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0xbb/0xd0 kernel/locking/spinlock.c:184 try_to_wake_up+0x10a/0x12e0 kernel/sched/core.c:2061 wake_up_process kernel/sched/core.c:2129 [inline] wake_up_q+0xa4/0x100 kernel/sched/core.c:440 futex_wake+0x61f/0x760 kernel/futex.c:1556 do_futex+0x2e4/0x26d0 kernel/futex.c:3533 __do_sys_futex kernel/futex.c:3589 [inline] __se_sys_futex kernel/futex.c:3557 [inline] __x64_sys_futex+0x472/0x6a0 kernel/futex.c:3557 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd8b1360cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 000000000072c048 RCX: 0000000000457569 RDX: 00000000004cb688 RSI: 0000000000000081 RDI: 000000000072c04c RBP: 000000000072c040 R08: 0000000000000063 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 000000000072c04c R13: 00007ffc46f2c06f R14: 00007fd8b13619c0 R15: 0000000000000002 ====================================================== WARNING: possible circular locking dependency detected 4.19.0-rc7-next-20181012+ #93 Not tainted ------------------------------------------------------ syz-executor2/7594 is trying to acquire lock: 0000000022883115 ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 but task is already holding lock: 000000002e3254e3 (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:777 [inline] 000000002e3254e3 (&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:607 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 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:1125 [inline] task_fork_fair+0xb0/0x6d0 kernel/sched/fair.c:9752 sched_fork+0x443/0xba0 kernel/sched/core.c:2359 copy_process+0x2585/0x8760 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:408 arch_call_rest_init+0xe/0x1b start_kernel+0x9f0/0xa2b init/main.c:744 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 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:243 console_unlock+0x80c/0x1160 kernel/printk/printk.c:2426 vprintk_emit+0x33d/0x930 kernel/printk/printk.c:1921 vprintk_default+0x28/0x30 kernel/printk/printk.c:1962 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:1995 check_stack_usage kernel/exit.c:755 [inline] do_exit.cold.18+0x5b/0x21f 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:3840 __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:226 console_trylock+0x15/0xa0 kernel/printk/printk.c:2244 console_trylock_spinning kernel/printk/printk.c:1648 [inline] vprintk_emit+0x322/0x930 kernel/printk/printk.c:1920 vprintk_default+0x28/0x30 kernel/printk/printk.c:1962 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:1995 __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 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+0x66c/0x900 kernel/sched/core.c:2715 context_switch kernel/sched/core.c:2834 [inline] __schedule+0x8d7/0x21d0 kernel/sched/core.c:3480 preempt_schedule_common+0x1f/0xd0 kernel/sched/core.c:3604 preempt_schedule+0x4d/0x60 kernel/sched/core.c:3630 ___preempt_schedule+0x16/0x18 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0xbb/0xd0 kernel/locking/spinlock.c:184 try_to_wake_up+0x10a/0x12e0 kernel/sched/core.c:2061 wake_up_process kernel/sched/core.c:2129 [inline] wake_up_q+0xa4/0x100 kernel/sched/core.c:440 futex_wake+0x61f/0x760 kernel/futex.c:1556 do_futex+0x2e4/0x26d0 kernel/futex.c:3533 __do_sys_futex kernel/futex.c:3589 [inline] __se_sys_futex kernel/futex.c:3557 [inline] __x64_sys_futex+0x472/0x6a0 kernel/futex.c:3557 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-executor2/7594: #0: 000000002e3254e3 (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:777 [inline] #0: 000000002e3254e3 (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0x17a/0x58d lib/debugobjects.c:818 stack backtrace: CPU: 0 PID: 7594 Comm: syz-executor2 Not tainted 4.19.0-rc7-next-20181012+ #93 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+0x244/0x3ab lib/dump_stack.c:113 print_circular_bug.isra.35.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:2345 [inline] __lock_acquire+0x3445/0x4da0 kernel/locking/lockdep.c:3337 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3840 __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:226 console_trylock+0x15/0xa0 kernel/printk/printk.c:2244 console_trylock_spinning kernel/printk/printk.c:1648 [inline] vprintk_emit+0x322/0x930 kernel/printk/printk.c:1920 vprintk_default+0x28/0x30 kernel/printk/printk.c:1962 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:1995 __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 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+0x66c/0x900 kernel/sched/core.c:2715 context_switch kernel/sched/core.c:2834 [inline] __schedule+0x8d7/0x21d0 kernel/sched/core.c:3480 preempt_schedule_common+0x1f/0xd0 kernel/sched/core.c:3604 preempt_schedule+0x4d/0x60 kernel/sched/core.c:3630 ___preempt_schedule+0x16/0x18 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0xbb/0xd0 kernel/locking/spinlock.c:184 try_to_wake_up+0x10a/0x12e0 kernel/sched/core.c:2061 wake_up_process kernel/sched/core.c:2129 [inline] wake_up_q+0xa4/0x100 kernel/sched/core.c:440 futex_wake+0x61f/0x760 kernel/futex.c:1556 do_futex+0x2e4/0x26d0 kernel/futex.c:3533 __do_sys_futex kernel/futex.c:3589 [inline] __se_sys_futex kernel/futex.c:3557 [inline] __x64_sys_futex+0x472/0x6a0 kernel/futex.c:3557 Lost 19 message(s)! Kernel Offset: disabled Rebooting in 86400 seconds..