rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=27157, q=153036) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294982081-4294971579), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor4 R running task 22240 15195 6175 0x80000000 Call Trace: sched_show_task.cold.87+0x2b6/0x30a kernel/sched/core.c:5300 print_other_cpu_stall.cold.66+0x7dd/0x8bb kernel/rcu/tree.c:1286 check_cpu_stall kernel/rcu/tree.c:1415 [inline] rcu_pending kernel/rcu/tree.c:2961 [inline] rcu_check_callbacks+0xfe5/0x1400 kernel/rcu/tree.c:2506 update_process_times+0x2d/0x70 kernel/time/timer.c:1636 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274 __run_hrtimer kernel/time/hrtimer.c:1398 [inline] __hrtimer_run_queues+0x412/0x10c0 kernel/time/hrtimer.c:1460 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1518 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1034 [inline] smp_apic_timer_interrupt+0x1a1/0x750 arch/x86/kernel/apic/apic.c:1059 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:804 RIP: 0010:__sanitizer_cov_trace_pc+0x38/0x50 kernel/kcov.c:107 Code: 8b 15 6c 85 84 7e 81 e2 00 01 1f 00 48 8b 75 08 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 RSP: 0018:ffff880188456f10 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: ffff8801884572b8 RCX: ffffc90009eda000 RDX: 0000000000000002 RSI: ffffffff81f26d3b RDI: 0000000000000006 RBP: ffff880188456f10 R08: ffff880181878600 R09: ffffed00397c3b05 R10: ffffed00397c3b05 R11: ffff8801cbe1d82f R12: 00000025c0550000 R13: dffffc0000000000 R14: 00000025c0600000 R15: ffff880188456fd0 add_to_pagemap fs/proc/task_mmu.c:1192 [inline] pagemap_pte_hole+0x26b/0x690 fs/proc/task_mmu.c:1217 walk_pud_range mm/pagewalk.c:86 [inline] walk_p4d_range mm/pagewalk.c:135 [inline] walk_pgd_range mm/pagewalk.c:161 [inline] __walk_page_range+0x6e9/0x17e0 mm/pagewalk.c:254 walk_page_range+0x255/0x520 mm/pagewalk.c:335 pagemap_read+0x8fd/0xb50 fs/proc/task_mmu.c:1509 do_loop_readv_writev fs/read_write.c:700 [inline] do_iter_read+0x4a3/0x650 fs/read_write.c:924 vfs_readv+0x175/0x1c0 fs/read_write.c:986 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x53c/0xb20 fs/splice.c:417 do_splice_to+0x12e/0x190 fs/splice.c:881 splice_direct_to_actor+0x270/0x8f0 fs/splice.c:953 do_splice_direct+0x2d4/0x420 fs/splice.c:1062 do_sendfile+0x62a/0xe20 fs/read_write.c:1440 __do_sys_sendfile64 fs/read_write.c:1495 [inline] __se_sys_sendfile64 fs/read_write.c:1487 [inline] __x64_sys_sendfile64+0x15d/0x250 fs/read_write.c:1487 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457579 Code: 1d b4 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f55151dcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457579 RDX: 00000000200000c0 RSI: 0000000000000007 RDI: 0000000000000004 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000080000002 R11: 0000000000000246 R12: 00007f55151dd6d4 R13: 00000000004c34e4 R14: 00000000004d5298 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10502 jiffies! g27157 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 22608 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2830 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3479 schedule+0xfe/0x460 kernel/sched/core.c:3523 schedule_timeout+0x140/0x260 kernel/time/timer.c:1804 rcu_gp_fqs_loop+0x762/0xa80 kernel/rcu/tree.c:1934 rcu_gp_kthread+0x341/0xc70 kernel/rcu/tree.c:2090 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352