rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=53465, q=208) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294986777-4294976275), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.4 R running task 28480 19214 7673 0x00000008 Call Trace: sched_show_task kernel/sched/core.c:5297 [inline] sched_show_task.cold+0x2ee/0x35d kernel/sched/core.c:5272 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:1636 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:1398 [inline] __hrtimer_run_queues+0x33b/0xdc0 kernel/time/hrtimer.c:1460 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1518 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:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:94 Code: 41 bc f4 ff ff ff e8 f3 66 ea ff 48 c7 05 44 16 cd 08 00 00 00 00 e9 ca e9 ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 48 89 e5 48 8b 75 08 65 48 8b 04 25 40 ee 01 00 65 8b 15 28 8b RSP: 0018:ffff8880ae907b58 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: ffff88805e826600 RBX: 0000000005800001 RCX: ffffffff815b5377 RDX: 0000000000000100 RSI: ffffffff815b5276 RDI: 0000000000000005 RBP: ffff8880ae907ba8 R08: ffff88805e826600 R09: ffffed1011e8edd6 R10: ffffed1011e8edd5 R11: ffff88808f476eab R12: ffff8880ae923a00 R13: 0000000000023a00 R14: ffff88808f4770b0 R15: ffffed1011e8ee1a __mod_timer kernel/time/timer.c:1010 [inline] mod_timer+0x78c/0x1030 kernel/time/timer.c:1102 pie_timer+0x60d/0x790 net/sched/sch_pie.c:438 call_timer_fn+0x18d/0x720 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers kernel/time/timer.c:1682 [inline] __run_timers kernel/time/timer.c:1650 [inline] run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1695 __do_softirq+0x25c/0x921 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 RIP: 0010:__write_once_size include/linux/compiler.h:220 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x48/0x50 kernel/kcov.c:109 Code: 75 2b 8b 90 d0 12 00 00 83 fa 02 75 20 48 8b 88 d8 12 00 00 8b 80 d4 12 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 <48> 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 40 ee 01 00 65 8b 05 e0 8a RSP: 0018:ffff888032837ac8 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: ffff88802c027b00 RCX: ffffc9000eac5000 RDX: 0000000000000226 RSI: ffffffff81603757 RDI: 0000000000000001 RBP: ffff888032837ac8 R08: ffff88805e826600 R09: ffffed100b4840c5 R10: ffffed100b4840c4 R11: ffff88805a420623 R12: ffff88805a420600 R13: ffff888032837b58 R14: ffff88805a420620 R15: 00000000ffffffff mark_wake_futex+0x77/0x170 kernel/futex.c:1446 futex_wake+0x3e3/0x4d0 kernel/futex.c:1609 do_futex+0x358/0x1d70 kernel/futex.c:3651 __do_sys_futex kernel/futex.c:3707 [inline] __se_sys_futex kernel/futex.c:3675 [inline] __x64_sys_futex+0x400/0x590 kernel/futex.c:3675 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a09 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1d41ca8cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 000000000075c078 RCX: 0000000000459a09 RDX: 00000000004c599b RSI: 0000000000000081 RDI: 000000000075c07c RBP: 000000000075c070 R08: 0000000000000009 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 000000000075c07c R13: 00007ffe0b0bd04f R14: 00007f1d41ca99c0 R15: 000000000075c07c rcu: rcu_preempt kthread starved for 10502 jiffies! g53465 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:3474 schedule+0x92/0x1c0 kernel/sched/core.c:3518 schedule_timeout+0x4db/0xfc0 kernel/time/timer.c:1804 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