rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=71889, q=69) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295001261-4294990758), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.0 R running task 25552 29849 8711 0x00004000 Call Trace: sched_show_task kernel/sched/core.c:5285 [inline] sched_show_task.cold+0x291/0x2fc kernel/sched/core.c:5260 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] check_cpu_stall kernel/rcu/tree_stall.h:536 [inline] rcu_pending kernel/rcu/tree.c:2625 [inline] rcu_sched_clock_irq.cold+0xaaf/0xbfd kernel/rcu/tree.c:2161 update_process_times+0x32/0x80 kernel/time/timer.c:1639 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1296 __run_hrtimer kernel/time/hrtimer.c:1388 [inline] __hrtimer_run_queues+0x33b/0xdd0 kernel/time/hrtimer.c:1450 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1508 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1066 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:68 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x11/0x50 kernel/kcov.c:102 Code: 48 c7 05 fe d3 15 09 00 00 00 00 e9 a4 e9 ff ff 90 90 90 90 90 90 90 90 90 55 48 89 e5 48 8b 75 08 65 48 8b 04 25 c0 fd 01 00 <65> 8b 15 20 fe 90 7e 81 e2 00 01 1f 00 75 2b 8b 90 f0 12 00 00 83 RSP: 0018:ffff8880942ff388 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff8880939b62c0 RBX: 0000000000000001 RCX: ffffc90005de1000 RDX: 0000000000040000 RSI: ffffffff83362e0c RDI: 0000000000000005 RBP: ffff8880942ff388 R08: ffff8880939b62c0 R09: 0000000000000004 R10: ffffed1015d06c6f R11: ffff8880ae83637b R12: 0000000000000000 R13: 0000000000000000 R14: 0000000080000000 R15: ffff8880942ff4a8 debug_smp_processor_id+0x3c/0x2b0 lib/smp_processor_id.c:57 rcu_dynticks_curr_cpu_in_eqs+0x17/0xb0 kernel/rcu/tree.c:290 rcu_is_watching+0x10/0x30 kernel/rcu/tree.c:872 rcu_read_unlock include/linux/rcupdate.h:643 [inline] wb_get_create_current include/linux/backing-dev.h:304 [inline] balance_dirty_pages_ratelimited+0x11fe/0x1f00 mm/page-writeback.c:1874 generic_perform_write+0x353/0x520 mm/filemap.c:3311 __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3404 ext4_file_write_iter+0x332/0x1070 fs/ext4/file.c:266 call_write_iter include/linux/fs.h:1870 [inline] do_iter_readv_writev+0x5f8/0x8f0 fs/read_write.c:693 do_iter_write fs/read_write.c:970 [inline] do_iter_write+0x184/0x610 fs/read_write.c:951 vfs_iter_write+0x77/0xb0 fs/read_write.c:983 iter_file_splice_write+0x65c/0xbd0 fs/splice.c:746 do_splice_from fs/splice.c:848 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1020 splice_direct_to_actor+0x366/0x970 fs/splice.c:975 do_splice_direct+0x1da/0x2a0 fs/splice.c:1063 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4592c9 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:00007f674cd6ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000004592c9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 00008000fffffffe R11: 0000000000000246 R12: 00007f674cd6f6d4 R13: 00000000004c689d R14: 00000000004db828 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10556 jiffies! g71889 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29224 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:2818 [inline] __schedule+0x7c5/0x1560 kernel/sched/core.c:3444 schedule+0xa8/0x260 kernel/sched/core.c:3508 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807 rcu_gp_fqs_loop kernel/rcu/tree.c:1589 [inline] rcu_gp_kthread+0x9b2/0x18b0 kernel/rcu/tree.c:1746 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352