rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=470681, q=30) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295196706-4295186203), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.2 R running task 28944 22695 8140 0x00000000 Call Trace: sched_show_task kernel/sched/core.c:5338 [inline] sched_show_task.cold+0x2ee/0x35d kernel/sched/core.c:5313 print_other_cpu_stall kernel/rcu/tree.c:1430 [inline] check_cpu_stall kernel/rcu/tree.c:1557 [inline] __rcu_pending kernel/rcu/tree.c:3293 [inline] rcu_pending kernel/rcu/tree.c:3336 [inline] rcu_check_callbacks.cold+0xaa1/0xd90 kernel/rcu/tree.c:2682 update_process_times+0x32/0x80 kernel/time/timer.c:1638 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:164 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1274 __run_hrtimer kernel/time/hrtimer.c:1401 [inline] __hrtimer_run_queues+0x33b/0xdc0 kernel/time/hrtimer.c:1463 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1521 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline] smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1092 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x54/0x90 kernel/locking/spinlock.c:192 Code: c0 d8 5b f2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 33 48 83 3d ed 73 9c 01 00 74 20 fb 66 0f 1f 44 00 00 01 00 00 00 e8 82 f8 f2 f9 65 8b 05 cb 05 ac 78 85 c0 74 06 41 RSP: 0000:ffff88804f11fc18 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff11e4b7b RBX: 0000000000000000 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880283a6afc RBP: ffff88804f11fc20 R08: ffff8880283a6280 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888087da1448 R13: ffff888087da0d80 R14: 000000000000000a R15: 000000000000000b spin_unlock_irq include/linux/spinlock.h:379 [inline] get_signal+0x198e/0x1fc0 kernel/signal.c:2581 do_signal+0x95/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x293/0x2f0 arch/x86/entry/common.c:198 retint_user+0x8/0x18 RIP: 0033:0x4057e9 Code: d0 ff ff ff 01 48 8b 7c 24 28 c7 44 24 34 00 00 00 00 e8 7a d9 01 00 85 c0 75 23 48 6b 44 24 20 18 8b 7c 24 1c 48 03 44 24 38 <48> 8b 48 10 48 8b 50 08 48 8b 30 e8 17 f5 00 00 89 44 24 34 64 f0 RSP: 002b:00007fa603a7ca70 EFLAGS: 00010206 RAX: 0000000022b4b118 RBX: 0000000000000007 RCX: 0000000000414d47 RDX: 8df4064c8803b078 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 000000000075c1c0 R08: 00007fa603a7ca70 R09: 000000000075c1c0 R10: 0000000000000000 R11: 0000000000000000 R12: 00007fa603a7d6d4 R13: 00000000004cbf38 R14: 00000000004e6c10 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10533 jiffies! g470681 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29104 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x866/0x1dc0 kernel/sched/core.c:3515 schedule+0x92/0x1c0 kernel/sched/core.c:3559 schedule_timeout+0x4db/0xfc0 kernel/time/timer.c:1806 rcu_gp_kthread+0xd5c/0x2190 kernel/rcu/tree.c:2202 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415