rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=d02/1/0x4000000000000002 softirq=12317/12318 fqs=3 
	(t=10500 jiffies g=17493 q=22)
rcu: rcu_preempt kthread starved for 10493 jiffies! g17493 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28800    10      2 0x80004000
Call Trace:
 schedule+0xd0/0x2a0 kernel/sched/core.c:4168
 schedule_timeout+0x35c/0x850 kernel/time/timer.c:1898
 rcu_gp_fqs_loop kernel/rcu/tree.c:1674 [inline]
 rcu_gp_kthread+0x9bf/0x1960 kernel/rcu/tree.c:1836
 kthread+0x388/0x470 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 9281 Comm: syz-executor.4 Not tainted 5.6.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x19b/0x1e5 kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:475 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:549 [inline]
 rcu_pending kernel/rcu/tree.c:3225 [inline]
 rcu_sched_clock_irq.cold+0x55d/0xcfa kernel/rcu/tree.c:2296
 update_process_times+0x25/0x60 kernel/time/timer.c:1727
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176
 tick_sched_timer+0x4e/0x140 kernel/time/tick-sched.c:1320
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x5ca/0xed0 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 [inline]
 smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1138
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:187
Code: 0f 1f 84 00 00 00 00 00 65 48 8b 04 25 00 1f 02 00 65 8b 15 48 ed 8e 7e 81 e2 00 01 1f 00 48 8b 34 24 75 2b 8b 90 d8 13 00 00 <83> fa 02 75 20 48 8b 88 e0 13 00 00 8b 80 dc 13 00 00 48 8b 11 48
RSP: 0000:ffffc90001747948 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff8880951240c0 RBX: ffffea0000c4ddc0 RCX: ffffffff81c8a2d5
RDX: 0000000000000002 RSI: ffffffff81c8a2e3 RDI: 0000000000000007
RBP: ffffea0000c4ddc0 R08: ffff8880951240c0 R09: ffffed1012a24819
R10: ffff8880951240c7 R11: ffffed1012a24818 R12: ffffea0000c4ddc8
R13: 0000000000000000 R14: dead000000000100 R15: ffff8880a88d7078
 PageUptodate include/linux/page-flags.h:496 [inline]
 page_cache_pipe_buf_confirm+0x73/0x2d0 fs/splice.c:109
 pipe_buf_confirm include/linux/pipe_fs_i.h:197 [inline]
 iter_file_splice_write+0x547/0xb00 fs/splice.c:746
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0x115/0x160 fs/splice.c:1037
 splice_direct_to_actor+0x38c/0x980 fs/splice.c:992
 do_splice_direct+0x1b4/0x280 fs/splice.c:1080
 do_sendfile+0x555/0xc50 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+0x149/0x210 fs/read_write.c:1567
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c879
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:00007f00d8514c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f00d85156d4 RCX: 000000000045c879
RDX: 00000000200001c0 RSI: 0000000000000004 RDI: 0000000000000004
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008d4 R14: 00000000004cb7a6 R15: 000000000076bf0c