kvm: emulating exchange as write
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=7029, q=9)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295015275-4295004773), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor855 R  running task    28120  8454   8328 0x00000800
Call Trace:
 <IRQ>
 sched_show_task kernel/sched/core.c:5338 [inline]
 sched_show_task.cold+0x2e2/0x343 kernel/sched/core.c:5313
 print_other_cpu_stall kernel/rcu/tree.c:1430 [inline]
 check_cpu_stall kernel/rcu/tree.c:1557 [inline]
 __rcu_pending kernel/rcu/tree.c:3293 [inline]
 rcu_pending kernel/rcu/tree.c:3336 [inline]
 rcu_check_callbacks.cold+0xaf0/0xddc kernel/rcu/tree.c:2682
 update_process_times+0x2a/0x70 kernel/time/timer.c:1638
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:168
 tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1278
 __run_hrtimer kernel/time/hrtimer.c:1401 [inline]
 __hrtimer_run_queues+0x2fc/0xd50 kernel/time/hrtimer.c:1463
 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1521
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline]
 smp_apic_timer_interrupt+0x10c/0x550 arch/x86/kernel/apic/apic.c:1092
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
 </IRQ>
RIP: 0010:vcpu_enter_guest+0xed3/0x5ed0 arch/x86/kvm/x86.c:7831
Code: ff df 48 c1 e8 03 80 3c 10 00 0f 85 cb 44 00 00 48 83 3d 67 2f a6 07 00 0f 84 c0 36 00 00 e8 84 71 5b 00 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 13 73 3a 00 65 8b 1d 7c c6 f5 7e 31 ff 89 de e8
RSP: 0018:ffff88809fa37a30 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffff88809f51e540 RBX: ffff88809f51e540 RCX: 1ffff11013ea3dbc
RDX: 0000000000000000 RSI: ffffffff810c273c RDI: ffff88809f51edbc
RBP: ffff88809fa37b40 R08: ffff88809f51e540 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880a4f306c0
R13: ffff8880a4f306ec R14: fffffe92e03ed1ee R15: 0000000000000000
 vcpu_run arch/x86/kvm/x86.c:7913 [inline]
 kvm_arch_vcpu_ioctl_run+0x446/0x16a0 arch/x86/kvm/x86.c:8113
 kvm_vcpu_ioctl+0x493/0xe20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2667
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x44a9e9
Code: e8 ec e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 1b ff fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0d0e1e4ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dfc58 RCX: 000000000044a9e9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000008
RBP: 00000000006dfc50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dfc5c
R13: 00007ffec2d9748f R14: 00007f0d0e1e59c0 R15: 0000000000000005
rcu: rcu_preempt kthread starved for 10502 jiffies! g7029 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 0x80000000
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_timeout+0x4d1/0xf20 kernel/time/timer.c:1806
 rcu_gp_kthread+0xcee/0x2060 kernel/rcu/tree.c:2202
 kthread+0x34a/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415