rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=210021, q=4) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295115664-4295105161), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.3 R running task 26232 18803 9578 0x00004000 Call Trace: sched_show_task kernel/sched/core.c:5952 [inline] sched_show_task.cold+0x2ee/0x35d kernel/sched/core.c:5927 print_other_cpu_stall kernel/rcu/tree_stall.h:430 [inline] check_cpu_stall kernel/rcu/tree_stall.h:558 [inline] rcu_pending kernel/rcu/tree.c:3030 [inline] rcu_sched_clock_irq.cold+0xb23/0xc37 kernel/rcu/tree.c:2276 update_process_times+0x2d/0x70 kernel/time/timer.c:1726 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:171 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1314 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1119 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1144 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:180 Code: cc cc cc cc cc cc cc cc cc 65 48 8b 04 25 c0 1e 02 00 48 8b 80 98 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 55 <48> 89 e5 65 48 8b 04 25 c0 1e 02 00 65 8b 15 44 8d 8c 7e 81 e2 00 RSP: 0018:ffffc900143cf4d0 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff13 RAX: 00000000000002b8 RBX: dffffc0000000000 RCX: 0000000000000d48 RDX: 0000000000040000 RSI: ffffffff8193936c RDI: ffff888091e14520 RBP: ffffc900143cf5f0 R08: ffff888049c36080 R09: fffffbfff16a337e R10: fffffbfff16a337d R11: ffffffff8b519bef R12: 0000000000000017 R13: ffffc900143cf5c8 R14: ffff888091e14410 R15: ffffc900143cfa00 ext4_buffered_write_iter+0x1fe/0x460 fs/ext4/file.c:270 ext4_file_write_iter+0x1fe/0x14e0 fs/ext4/file.c:642 call_write_iter include/linux/fs.h:1901 [inline] do_iter_readv_writev+0x5f8/0x8f0 fs/read_write.c:693 do_iter_write fs/read_write.c:998 [inline] do_iter_write+0x184/0x610 fs/read_write.c:979 vfs_iter_write+0x77/0xb0 fs/read_write.c:1039 iter_file_splice_write+0x717/0xc10 fs/splice.c:760 do_splice_from fs/splice.c:863 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1037 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:992 do_splice_direct+0x1da/0x2a0 fs/splice.c:1080 do_sendfile+0x597/0xd00 fs/read_write.c:1520 __do_sys_sendfile64 fs/read_write.c:1575 [inline] __se_sys_sendfile64 fs/read_write.c:1567 [inline] __x64_sys_sendfile64+0x15a/0x220 fs/read_write.c:1567 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c6c9 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:00007fa1f2bb4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fa1f2bb56d4 RCX: 000000000045c6c9 RDX: 00000000200001c0 RSI: 0000000000000006 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008d0 R14: 00000000004cb5e8 R15: 000000000076bf2c rcu: rcu_preempt kthread starved for 10558 jiffies! g210021 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29152 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1658 [inline] rcu_gp_kthread+0xa10/0x1940 kernel/rcu/tree.c:1818 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352