====================================================== WARNING: possible circular locking dependency detected 5.0.0+ #15 Not tainted ------------------------------------------------------ syz-executor773/7680 is trying to acquire lock: 00000000c05ca8f5 ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 but task is already holding lock: 00000000ff5f4b54 (&base->lock){-.-.}, at: lock_timer_base+0x56/0x1b0 kernel/time/timer.c:937 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&base->lock){-.-.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 lock_timer_base+0x56/0x1b0 kernel/time/timer.c:937 __mod_timer kernel/time/timer.c:1009 [inline] mod_timer kernel/time/timer.c:1101 [inline] add_timer+0x108/0xbe0 kernel/time/timer.c:1137 __queue_delayed_work+0x1af/0x270 kernel/workqueue.c:1649 queue_delayed_work_on+0x19a/0x200 kernel/workqueue.c:1674 queue_delayed_work include/linux/workqueue.h:509 [inline] schedule_delayed_work include/linux/workqueue.h:610 [inline] psi_task_change+0x409/0x610 kernel/sched/psi.c:546 psi_enqueue kernel/sched/stats.h:82 [inline] enqueue_task kernel/sched/core.c:770 [inline] activate_task+0x1f8/0x470 kernel/sched/core.c:794 wake_up_new_task+0x50d/0xbd0 kernel/sched/core.c:2469 _do_fork+0x34f/0xfd0 kernel/fork.c:2251 kernel_thread+0x34/0x40 kernel/fork.c:2285 rest_init+0x28/0x37b init/main.c:408 arch_call_rest_init+0xe/0x1b start_kernel+0x803/0x83c init/main.c:739 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #2 (&rq->lock){-.-.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 rq_lock kernel/sched/sched.h:1168 [inline] task_fork_fair+0x6a/0x520 kernel/sched/fair.c:10136 sched_fork+0x3b2/0x900 kernel/sched/core.c:2405 copy_process.part.0+0x188c/0x7980 kernel/fork.c:1886 copy_process kernel/fork.c:1709 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2226 kernel_thread+0x34/0x40 kernel/fork.c:2285 rest_init+0x28/0x37b init/main.c:408 arch_call_rest_init+0xe/0x1b start_kernel+0x803/0x83c init/main.c:739 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #1 (&p->pi_lock){-.-.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 try_to_wake_up+0x8f/0x1000 kernel/sched/core.c:2008 wake_up_process+0x10/0x20 kernel/sched/core.c:2172 __up.isra.0+0x136/0x1a0 kernel/locking/semaphore.c:262 up+0x9c/0xe0 kernel/locking/semaphore.c:187 __up_console_sem+0xb7/0x1c0 kernel/printk/printk.c:236 console_unlock+0x681/0xeb0 kernel/printk/printk.c:2476 vprintk_emit+0x280/0x6d0 kernel/printk/printk.c:1981 vprintk_default+0x28/0x30 kernel/printk/printk.c:2008 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2041 check_stack_usage kernel/exit.c:764 [inline] do_exit.cold+0x5d/0x254 kernel/exit.c:926 do_group_exit+0x135/0x370 kernel/exit.c:980 __do_sys_exit_group kernel/exit.c:991 [inline] __se_sys_exit_group kernel/exit.c:989 [inline] __x64_sys_exit_group+0x44/0x50 kernel/exit.c:989 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 ((console_sem).lock){-.-.}: check_prevs_add kernel/locking/lockdep.c:2324 [inline] validate_chain kernel/locking/lockdep.c:2705 [inline] __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3692 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0xa8/0x210 kernel/printk/printk.c:219 console_trylock+0x15/0xa0 kernel/printk/printk.c:2292 console_trylock_spinning kernel/printk/printk.c:1705 [inline] vprintk_emit+0x267/0x6d0 kernel/printk/printk.c:1980 vprintk_default+0x28/0x30 kernel/printk/printk.c:2008 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2041 fail_dump lib/fault-inject.c:44 [inline] should_fail+0x708/0x852 lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1610 slab_pre_alloc_hook mm/slab.h:419 [inline] slab_alloc mm/slab.c:3378 [inline] kmem_cache_alloc+0x47/0x6f0 mm/slab.c:3554 kmem_cache_zalloc include/linux/slab.h:730 [inline] fill_pool lib/debugobjects.c:134 [inline] __debug_object_init+0x755/0xc30 lib/debugobjects.c:379 debug_object_init lib/debugobjects.c:431 [inline] debug_object_activate+0x2b8/0x4f0 lib/debugobjects.c:512 debug_timer_activate kernel/time/timer.c:708 [inline] debug_activate kernel/time/timer.c:763 [inline] __mod_timer kernel/time/timer.c:1040 [inline] mod_timer kernel/time/timer.c:1101 [inline] add_timer+0x3ad/0xbe0 kernel/time/timer.c:1137 __queue_delayed_work+0x1af/0x270 kernel/workqueue.c:1649 queue_delayed_work_on+0x19a/0x200 kernel/workqueue.c:1674 queue_delayed_work include/linux/workqueue.h:509 [inline] schedule_delayed_work include/linux/workqueue.h:610 [inline] unaccount_event kernel/events/core.c:4317 [inline] _free_event+0xe6f/0x13b0 kernel/events/core.c:4425 put_event+0x47/0x60 kernel/events/core.c:4538 perf_event_release_kernel+0x693/0xc60 kernel/events/core.c:4644 perf_release+0x37/0x50 kernel/events/core.c:4654 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: (console_sem).lock --> &rq->lock --> &base->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&base->lock); lock(&rq->lock); lock(&base->lock); lock((console_sem).lock); *** DEADLOCK *** 1 lock held by syz-executor773/7680: #0: 00000000ff5f4b54 (&base->lock){-.-.}, at: lock_timer_base+0x56/0x1b0 kernel/time/timer.c:937 stack backtrace: CPU: 0 PID: 7680 Comm: syz-executor773 Not tainted 5.0.0+ #15 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+0x172/0x1f0 lib/dump_stack.c:113 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1562 check_prev_add.constprop.0+0xf11/0x23c0 kernel/locking/lockdep.c:2211 check_prevs_add kernel/locking/lockdep.c:2324 [inline] validate_chain kernel/locking/lockdep.c:2705 [inline] __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3692 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0xa8/0x210 kernel/printk/printk.c:219 console_trylock+0x15/0xa0 kernel/printk/printk.c:2292 console_trylock_spinning kernel/printk/printk.c:1705 [inline] vprintk_emit+0x267/0x6d0 kernel/printk/printk.c:1980 vprintk_default+0x28/0x30 kernel/printk/printk.c:2008 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2041 fail_dump lib/fault-inject.c:44 [inline] should_fail+0x708/0x852 lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1610 slab_pre_alloc_hook mm/slab.h:419 [inline] slab_alloc mm/slab.c:3378 [inline] kmem_cache_alloc+0x47/0x6f0 mm/slab.c:3554 kmem_cache_zalloc include/linux/slab.h:730 [inline] fill_pool lib/debugobjects.c:134 [inline] __debug_object_init+0x755/0xc30 lib/debugobjects.c:379 debug_object_init lib/debugobjects.c:431 [inline] debug_object_activate+0x2b8/0x4f0 lib/debugobjects.c:512 debug_timer_activate kernel/time/timer.c:708 [inline] debug_activate kernel/time/timer.c:763 [inline] __mod_timer kernel/time/timer.c:1040 [inline] mod_timer kernel/time/timer.c:1101 [inline] add_timer+0x3ad/0xbe0 kernel/time/timer.c:1137 __queue_delayed_work+0x1af/0x270 kernel/workqueue.c:1649 queue_delayed_work_on+0x19a/0x200 kernel/workqueue.c:1674 queue_delayed_work include/linux/workqueue.h:509 [inline] schedule_delayed_work include/linux/workqueue.h:610 [inline] unaccount_event kernel/events/core.c:4317 [inline] _free_event+0xe6f/0x13b0 kernel/events/core.c:4425 put_event+0x47/0x60 kernel/events/core.c:4538 perf_event_release_kernel+0x693/0xc60 kernel/events/core.c:4644 perf_release+0x37/0x50 kernel/events/core.c:4654 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x44df59 Code: 4d c9 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 1b c9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f724395fcb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000021 RAX: 0000000000000006 RBX: 00007f724395fcc0 RCX: 000000000044df59 RDX: 0000000000000001 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000031 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e6a0c R13: 00007ffc2a98791f R14: 00007f72439609c0 R15: 0000000000000000