rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10499 ticks this GP) idle=0fa/1/0x4000000000000000 softirq=8018/8018 fqs=5234 
	(t=10500 jiffies g=6429 q=525)
NMI backtrace for cpu 0
CPU: 0 PID: 7039 Comm: syz-executor.0 Not tainted 5.8.0-rc6-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+0x1f0/0x31e lib/dump_stack.c:118
 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x199/0x2a0 kernel/rcu/tree_stall.h:320
 print_cpu_stall kernel/rcu/tree_stall.h:553 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:627 [inline]
 rcu_pending kernel/rcu/tree.c:3489 [inline]
 rcu_sched_clock_irq+0x1928/0x1eb0 kernel/rcu/tree.c:2504
 update_process_times+0x12c/0x180 kernel/time/timer.c:1737
 tick_sched_handle kernel/time/tick-sched.c:176 [inline]
 tick_sched_timer+0x254/0x410 kernel/time/tick-sched.c:1320
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x42d/0x930 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x373/0xd60 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xf0/0x260 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_apic_timer_interrupt+0xb9/0x130 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:585
RIP: 0010:bvec_iter_advance include/linux/bvec.h:110 [inline]
RIP: 0010:iov_iter_copy_from_user_atomic+0x980/0xda0 lib/iov_iter.c:1000
Code: 3d 8b 5c 24 10 ff c3 e8 ce b7 d8 fd eb af 44 89 f1 80 e1 07 80 c1 03 38 c1 7c cf 4c 89 f7 e8 17 c6 17 fe eb c5 e8 b0 b7 d8 fd <45> 31 e4 eb 23 e8 a6 b7 d8 fd 48 8b 5c 24 08 49 89 ee eb 14 49 89
RSP: 0018:ffffc90001be7838 EFLAGS: 00000293
RAX: ffffffff839bda50 RBX: 1ffff1101226ef41 RCX: ffff8880913765c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff839bd9d7 R09: ffffffff839bd2e8
R10: 0000000000000002 R11: ffff8880913765c0 R12: 0000000000000000
R13: ffffc90001be7d10 R14: ffff888085453000 R15: 0005088000000000
 generic_perform_write+0x2ba/0x4e0 mm/filemap.c:3326
 ext4_buffered_write_iter+0x44d/0x5d0 fs/ext4/file.c:270
 ext4_file_write_iter+0x88d/0x1930 include/linux/fs.h:805
 do_iter_readv_writev+0x5b7/0x820 include/linux/fs.h:1902
 do_iter_write+0x16a/0x540 fs/read_write.c:1018
 iter_file_splice_write+0x6ca/0xdf0 fs/splice.c:750
 do_splice_from fs/splice.c:846 [inline]
 do_splice+0xdd1/0x1a50 fs/splice.c:1144
 __do_sys_splice fs/splice.c:1419 [inline]
 __se_sys_splice fs/splice.c:1401 [inline]
 __x64_sys_splice+0x14f/0x1f0 fs/splice.c:1401
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c369
Code: Bad RIP value.
RSP: 002b:00007f0ef7fffc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 0000000000032240 RCX: 000000000045c369
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 000000000078bf58 R08: 000000000000ffe0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffda584464f R14: 00007f0ef80009c0 R15: 000000000078bf0c