rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=dba/1/0x4000000000000004 softirq=290880/290880 fqs=0 (t=10500 jiffies g=447797 q=123) rcu: rcu_preempt kthread starved for 10500 jiffies! g447797 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29256 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x755/0x1580 kernel/sched/core.c:3880 schedule+0xd9/0x260 kernel/sched/core.c:3947 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807 rcu_gp_fqs_loop kernel/rcu/tree.c:1611 [inline] rcu_gp_kthread+0x9b2/0x18c0 kernel/rcu/tree.c:1768 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 3143 Comm: syz-executor.0 Not tainted 5.3.0-rc8 #0 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 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2736 [inline] rcu_sched_clock_irq.cold+0x4dd/0xc13 kernel/rcu/tree.c:2183 update_process_times+0x32/0x80 kernel/time/timer.c:1639 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1106 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1131 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x95/0xe0 kernel/locking/spinlock.c:191 Code: 48 c7 c0 50 f4 d2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 39 48 83 3d 72 c9 94 01 00 74 24 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 9c 96 10 fa 65 8b 05 0d d3 c3 78 RSP: 0018:ffff8880ae809b80 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff11a5e8a RBX: 0000000000000286 RCX: 1ffffffff134b5ee RDX: dffffc0000000000 RSI: ffffffff8177f14e RDI: 0000000000000286 RBP: ffff8880ae809b90 R08: ffff888045180440 R09: ffffed1015d04981 R10: ffffed1015d04980 R11: ffff8880ae824c03 R12: ffff8880ae824c00 R13: ffff8880ae824c00 R14: ffff8880ae824c00 R15: ffff8880ae824c00 __mod_timer kernel/time/timer.c:1053 [inline] mod_timer+0x507/0xc10 kernel/time/timer.c:1096 pie_timer+0x753/0x830 net/sched/sch_pie.c:454 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:537 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1133 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:97 [inline] RIP: 0010:do_raw_spin_unlock+0x44/0x270 kernel/locking/spinlock_debug.c:138 Code: 04 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 e7 01 00 00 41 81 7c 24 04 ad 4e ad de <0f> 85 9d 01 00 00 be 04 00 00 00 4c 89 e7 e8 c9 a3 52 00 4c 89 e2 RSP: 0018:ffff88802772f740 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: 0000000000000095 RCX: 1ffffffff134b5ee RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880a2d667e4 RBP: ffff88802772f758 R08: 1ffffffff134afaf R09: fffffbfff134afb0 R10: fffffbfff134afaf R11: ffffffff89a57d7f R12: ffff8880a2d667e0 R13: 0000000000000001 R14: 0000000000000002 R15: ffff88802772fcc0 __raw_spin_unlock include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock+0x23/0x50 kernel/locking/spinlock.c:183 spin_unlock include/linux/spinlock.h:378 [inline] lockref_get_not_dead+0x70/0x90 lib/lockref.c:217 legitimize_path.isra.0+0x87/0x1c0 fs/namei.c:623 unlazy_child fs/namei.c:740 [inline] lookup_fast+0xbef/0x11a0 fs/namei.c:1609 walk_component+0xef/0x2000 fs/namei.c:1804 link_path_walk.part.0+0x5ab/0x1340 fs/namei.c:2136 link_path_walk fs/namei.c:2070 [inline] path_openat+0x202/0x4630 fs/namei.c:3532 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_sys_open+0x3fe/0x5d0 fs/open.c:1089 __do_sys_open fs/open.c:1107 [inline] __se_sys_open fs/open.c:1102 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1102 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4137d1 Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007f2b80417bb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00000000004137d1 RDX: fffffffffffffff3 RSI: 0000000000000000 RDI: 00007f2b80417bd0 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000016 R10: 000000000000000b R11: 0000000000000293 R12: 00007f2b804186d4 R13: 00000000004c8ef7 R14: 00000000004dff48 R15: 00000000ffffffff