INFO: rcu detected stall in __check_object

Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported
INFO: rcu detected stall in kvm_vcpu_ioctl mm	C	error	unreliable	251	870d	2047d
FAT-fs (loop4): Unrecognized mount option "./fi.e1�" or missing value
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=9981, q=283)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294972288-4294961785), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor0   R  running task    21280  7720   5511 0x00000000
Call Trace:
 <IRQ>
 sched_show_task.cold.83+0x2b6/0x30a kernel/sched/core.c:5296
 print_other_cpu_stall.cold.79+0xa83/0xba5 kernel/rcu/tree.c:1430
 check_cpu_stall kernel/rcu/tree.c:1557 [inline]
 __rcu_pending kernel/rcu/tree.c:3276 [inline]
 rcu_pending kernel/rcu/tree.c:3319 [inline]
 rcu_check_callbacks+0xafc/0x1990 kernel/rcu/tree.c:2665
 update_process_times+0x2d/0x70 kernel/time/timer.c:1636
 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164
 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x41c/0x10d0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1029 [inline]
 smp_apic_timer_interrupt+0x1a1/0x760 arch/x86/kernel/apic/apic.c:1054
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:864
 </IRQ>
RIP: 0010:__nr_to_section include/linux/mmzone.h:1163 [inline]
RIP: 0010:pfn_valid include/linux/mmzone.h:1249 [inline]
RIP: 0010:__virt_addr_valid+0xfe/0x230 arch/x86/mm/physaddr.c:64
Code: ff 07 00 0f 87 b9 00 00 00 e8 ce 64 46 00 48 c7 c7 20 e0 3c 8b 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 00 01 00 00 4c 8b 2d 85 75 04 0a 4d 85 ed 0f 84 eb 00 00 00
RSP: 0018:ffff88018a1d68b8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: 0000000193be3c00 RCX: ffffc900060ed000
RDX: 1ffffffff1679c04 RSI: ffffffff81386a72 RDI: ffffffff8b3ce020
RBP: ffff88018a1d68d0 R08: ffff8801c071a040 R09: ffffed003277c780
R10: ffffed003277c781 R11: ffff880193be3c0e R12: 0000000000000032
R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000000f
 check_heap_object mm/usercopy.c:231 [inline]
 __check_object_size+0x15b/0x782 mm/usercopy.c:266
 check_object_size include/linux/thread_info.h:119 [inline]
 __copy_from_user include/linux/uaccess.h:74 [inline]
 __kvm_read_guest_page+0xda/0x130 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1737
 kvm_vcpu_read_guest_page+0x40/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1757
 kvm_fetch_guest_virt+0x149/0x1c0 arch/x86/kvm/x86.c:4878
 __do_insn_fetch_bytes+0x45b/0x950 arch/x86/kvm/emulate.c:896
 x86_decode_insn+0x1544/0x54c0 arch/x86/kvm/emulate.c:5107
 x86_emulate_instruction+0x89a/0x1f90 arch/x86/kvm/x86.c:6175
 kvm_mmu_page_fault+0x342/0x1ad0 arch/x86/kvm/mmu.c:5276
 handle_ept_violation+0x29e/0x6a0 arch/x86/kvm/vmx.c:7679
 vmx_handle_exit+0x2f7/0x17f0 arch/x86/kvm/vmx.c:10115
 vcpu_enter_guest+0x14a9/0x62e0 arch/x86/kvm/x86.c:7630
 vcpu_run arch/x86/kvm/x86.c:7693 [inline]
 kvm_arch_vcpu_ioctl_run+0x375/0x16e0 arch/x86/kvm/x86.c:7870
 kvm_vcpu_ioctl+0x72b/0x1150 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2590
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457099
Code: fd b4 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 b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f10ce81ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f10ce81b6d4 RCX: 0000000000457099
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cf730 R14: 00000000004c59b9 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10609 jiffies! g9981 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    22872    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2825 [inline]
 __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
 schedule+0xfe/0x460 kernel/sched/core.c:3517
 schedule_timeout+0x140/0x260 kernel/time/timer.c:1804
 rcu_gp_kthread+0x9d9/0x2310 kernel/rcu/tree.c:2194
 kthread+0x35a/0x420 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413