====================================================== WARNING: possible circular locking dependency detected 5.10.0-next-20201223-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/9817 is trying to acquire lock: ffffffff8b48b998 (allocation_wait.lock){..-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:137 but task is already holding lock: ffff8880b9e24898 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x5a/0x1f0 kernel/time/timer.c:944 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&base->lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159 lock_timer_base+0x5a/0x1f0 kernel/time/timer.c:944 __mod_timer+0x398/0xe30 kernel/time/timer.c:1017 __queue_delayed_work+0x1a7/0x270 kernel/workqueue.c:1655 queue_delayed_work_on+0xd1/0xe0 kernel/workqueue.c:1680 psi_task_change+0x142/0x220 kernel/sched/psi.c:807 psi_enqueue kernel/sched/stats.h:82 [inline] enqueue_task kernel/sched/core.c:1592 [inline] activate_task kernel/sched/core.c:1615 [inline] wake_up_new_task+0x9f2/0xdd0 kernel/sched/core.c:3834 kernel_clone+0x1f0/0xab0 kernel/fork.c:2489 kernel_thread+0xb5/0xf0 kernel/fork.c:2517 rest_init+0x23/0x388 init/main.c:687 start_kernel+0x470/0x491 init/main.c:1064 secondary_startup_64_no_verify+0xb0/0xbb -> #2 (&rq->lock){-.-.}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 rq_lock kernel/sched/sched.h:1318 [inline] task_fork_fair+0x74/0x4d0 kernel/sched/fair.c:10767 sched_fork+0x3fc/0xbd0 kernel/sched/core.c:3764 copy_process+0x1d61/0x6fc0 kernel/fork.c:2070 kernel_clone+0xe7/0xab0 kernel/fork.c:2465 kernel_thread+0xb5/0xf0 kernel/fork.c:2517 rest_init+0x23/0x388 init/main.c:687 start_kernel+0x470/0x491 init/main.c:1064 secondary_startup_64_no_verify+0xb0/0xbb -> #1 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159 try_to_wake_up+0x98/0x13b0 kernel/sched/core.c:3335 autoremove_wake_function+0x12/0x140 kernel/sched/wait.c:404 __wake_up_common+0x147/0x650 kernel/sched/wait.c:108 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:138 __kfence_alloc+0xa0/0xbc0 mm/kfence/core.c:710 kfence_alloc include/linux/kfence.h:108 [inline] slab_alloc_node mm/slub.c:2826 [inline] kmem_cache_alloc_node_trace+0x28d/0x3d0 mm/slub.c:2953 kmalloc_node include/linux/slab.h:570 [inline] kzalloc_node include/linux/slab.h:693 [inline] alloc_worker kernel/workqueue.c:1826 [inline] create_worker+0xfe/0x6d0 kernel/workqueue.c:1923 maybe_create_worker kernel/workqueue.c:2094 [inline] manage_workers kernel/workqueue.c:2146 [inline] worker_thread+0xaef/0x1120 kernel/workqueue.c:2393 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 -> #0 (allocation_wait.lock){..-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:2868 [inline] check_prevs_add kernel/locking/lockdep.c:2993 [inline] validate_chain kernel/locking/lockdep.c:3608 [inline] __lock_acquire+0x2ade/0x5500 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159 __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:137 __kfence_alloc+0xa0/0xbc0 mm/kfence/core.c:710 kfence_alloc include/linux/kfence.h:108 [inline] slab_alloc_node mm/slub.c:2826 [inline] slab_alloc mm/slub.c:2911 [inline] kmem_cache_alloc+0x259/0x470 mm/slub.c:2916 kmem_cache_zalloc include/linux/slab.h:672 [inline] fill_pool+0x264/0x5c0 lib/debugobjects.c:171 __debug_object_init+0x7a/0xd10 lib/debugobjects.c:560 debug_object_init lib/debugobjects.c:615 [inline] debug_object_activate+0x32c/0x3e0 lib/debugobjects.c:701 debug_timer_activate kernel/time/timer.c:727 [inline] __mod_timer+0x77d/0xe30 kernel/time/timer.c:1048 __queue_delayed_work+0x1a7/0x270 kernel/workqueue.c:1655 queue_delayed_work_on+0xd1/0xe0 kernel/workqueue.c:1680 queue_delayed_work include/linux/workqueue.h:522 [inline] schedule_delayed_work include/linux/workqueue.h:626 [inline] unaccount_event kernel/events/core.c:4703 [inline] _free_event+0xf49/0x1300 kernel/events/core.c:4812 put_event kernel/events/core.c:4935 [inline] perf_event_release_kernel+0xa24/0xe00 kernel/events/core.c:5050 perf_release+0x33/0x40 kernel/events/core.c:5060 __fput+0x283/0x920 fs/file_table.c:280 task_work_run+0xdd/0x190 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: allocation_wait.lock --> &rq->lock --> &base->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&base->lock); lock(&rq->lock); lock(&base->lock); lock(allocation_wait.lock); *** DEADLOCK *** 1 lock held by syz-executor.0/9817: #0: ffff8880b9e24898 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x5a/0x1f0 kernel/time/timer.c:944 stack backtrace: CPU: 0 PID: 9817 Comm: syz-executor.0 Not tainted 5.10.0-next-20201223-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2117 check_prev_add kernel/locking/lockdep.c:2868 [inline] check_prevs_add kernel/locking/lockdep.c:2993 [inline] validate_chain kernel/locking/lockdep.c:3608 [inline] __lock_acquire+0x2ade/0x5500 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159 __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:137 __kfence_alloc+0xa0/0xbc0 mm/kfence/core.c:710 kfence_alloc include/linux/kfence.h:108 [inline] slab_alloc_node mm/slub.c:2826 [inline] slab_alloc mm/slub.c:2911 [inline] kmem_cache_alloc+0x259/0x470 mm/slub.c:2916 kmem_cache_zalloc include/linux/slab.h:672 [inline] fill_pool+0x264/0x5c0 lib/debugobjects.c:171 __debug_object_init+0x7a/0xd10 lib/debugobjects.c:560 debug_object_init lib/debugobjects.c:615 [inline] debug_object_activate+0x32c/0x3e0 lib/debugobjects.c:701 debug_timer_activate kernel/time/timer.c:727 [inline] __mod_timer+0x77d/0xe30 kernel/time/timer.c:1048 __queue_delayed_work+0x1a7/0x270 kernel/workqueue.c:1655 queue_delayed_work_on+0xd1/0xe0 kernel/workqueue.c:1680 queue_delayed_work include/linux/workqueue.h:522 [inline] schedule_delayed_work include/linux/workqueue.h:626 [inline] unaccount_event kernel/events/core.c:4703 [inline] _free_event+0xf49/0x1300 kernel/events/core.c:4812 put_event kernel/events/core.c:4935 [inline] perf_event_release_kernel+0xa24/0xe00 kernel/events/core.c:5050 perf_release+0x33/0x40 kernel/events/core.c:5060 __fput+0x283/0x920 fs/file_table.c:280 task_work_run+0xdd/0x190 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x417bf1 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 a4 1a 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007ffe977a18a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000417bf1 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000ab3 R09: 00000000e0282ab7 R10: 00007ffe977a1980 R11: 0000000000000293 R12: 000000000119ca00 R13: 000000000119ca00 R14: 00000000000003e8 R15: 000000000119bf8c