rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=dce/1/0x4000000000000002 softirq=14856/14857 fqs=3 
	(t=10501 jiffies g=16025 q=31)
rcu: rcu_preempt kthread starved for 10496 jiffies! g16025 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29104    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:2818 [inline]
 __schedule+0x755/0x1580 kernel/sched/core.c:3444
 schedule+0xa8/0x270 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+0x9b2/0x18d0 kernel/rcu/tree.c:1746
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 11180 Comm: syz-executor.1 Not tainted 5.2.0-rc5-next-20190620 #19
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+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x22f/0x27f lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2625 [inline]
 rcu_sched_clock_irq.cold+0x4d1/0xc13 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+0x364/0xe40 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+0x12a/0x5b0 arch/x86/kernel/apic/apic.c:1066
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:95
Code: 25 d4 9b 15 09 41 bc f4 ff ff ff e8 1d de e9 ff 48 c7 05 be 9b 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 e0 b5 90
RSP: 0018:ffff88805798f938 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000040000 RBX: 0000000000000001 RCX: ffffc90007ff6000
RDX: 0000000000040000 RSI: ffffffff81c14d4e RDI: 0000000000000007
RBP: ffff88805798fb00 R08: ffff888091d5e580 R09: fffffbfff149f351
R10: fffffbfff149f350 R11: ffffffff8a4f9a87 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff8880a97fb780 R15: 0000000000000000
 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/0x6a0 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:00007f712a561c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000004592c9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 00008000fffffffe R11: 0000000000000246 R12: 00007f712a5626d4
R13: 00000000004c689d R14: 00000000004db828 R15: 00000000ffffffff