rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=6365, q=126) rcu: All QSes seen, last rcu_preempt kthread activity 10501 (4294953694-4294943193), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.0 R running task 27592 8244 8225 0x80004008 Call Trace: sched_show_task+0x40f/0x560 kernel/sched/core.c:5954 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] check_cpu_stall kernel/rcu/tree_stall.h:538 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0x1861/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:free_thread_stack+0x151/0x590 kernel/fork.c:280 Code: 31 f6 e8 42 af 6e 00 43 80 3c 2e 00 74 08 4c 89 e7 e8 43 a4 69 00 49 8b 1c 24 48 83 c3 08 48 89 d8 48 c1 e8 03 42 80 3c 28 00 <74> 08 48 89 df e8 25 a4 69 00 48 8b 3b be fc ff ff ff e8 28 04 00 RSP: 0018:ffffc900025d7b08 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff11012fbcbd1 RBX: ffff888097de5e88 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea00022c9440 RBP: ffffc900025d7b40 R08: dffffc0000000000 R09: fffffbfff12877ed R10: fffffbfff12877ed R11: 0000000000000000 R12: ffff888097de5f20 R13: dffffc0000000000 R14: 1ffff11012fbcbe4 R15: ffff8880a1437428 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_common kernel/sched/core.c:4236 [inline] preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261 ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0xcc/0xe0 kernel/locking/spinlock.c:191 spin_unlock_irqrestore include/linux/spinlock.h:393 [inline] fill_tgid_exit kernel/taskstats.c:274 [inline] taskstats_exit+0x30c/0xbb0 kernel/taskstats.c:601 do_exit+0x53f/0x2020 kernel/exit.c:782 do_group_exit+0x15c/0x2b0 kernel/exit.c:895 __do_sys_exit_group+0x17/0x20 kernel/exit.c:906 __se_sys_exit_group+0x14/0x20 kernel/exit.c:904 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:904 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a679 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffeb6a7e058 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000001e RCX: 000000000045a679 RDX: 0000000000414211 RSI: fffffffffffffff7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffff R09: 00007ffeb6a7e0b0 R10: 00000000007603a0 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffeb6a7e0b0 R14: 0000000000000000 R15: 00007ffeb6a7e0c0 rcu: rcu_preempt kthread starved for 10533 jiffies! g6365 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352