=============================
[ BUG: Invalid wait context ]
syzkaller #0 Tainted: G             L     
-----------------------------
swapper/1/0 is trying to lock:
ffff888035db1bb0 (&gpc->lock){....}-{3:3}, at: kvm_xen_set_evtchn_fast+0x253/0xe80 arch/x86/kvm/xen.c:1822
other info that might help us debug this:
context-{2:2}
locks held by swapper/1/0: 1, last CPU#1:
 #0: ffff888035db2110 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
 #0: ffff888035db2110 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
 #0: ffff888035db2110 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_set_evtchn_fast+0x245/0xe80 arch/x86/kvm/xen.c:1820
stack backtrace:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_lock_invalid_wait_context kernel/locking/lockdep.c:4846 [inline]
 check_wait_context kernel/locking/lockdep.c:4918 [inline]
 __lock_acquire+0x104c/0x1ec0 kernel/locking/lockdep.c:5203
 lock_acquire kernel/locking/lockdep.c:5886 [inline]
 lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
 _raw_read_lock_irqsave+0x46/0x90 kernel/locking/spinlock.c:271
 kvm_xen_set_evtchn_fast+0x253/0xe80 arch/x86/kvm/xen.c:1822
 xen_timer_callback+0x1db/0x2a0 arch/x86/kvm/xen.c:140
 __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
 __hrtimer_run_queues+0x13f/0x9c0 kernel/time/hrtimer.c:2124
 hrtimer_interrupt+0x441/0xaa0 kernel/time/hrtimer.c:2243
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: f8 a2 02 e9 43 4f 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 83 b0 24 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000177e00 EFLAGS: 00000202
RAX: 0000000000404957 RBX: ffff88801eef2580 RCX: ffffffff8bc6f115
RDX: 0000000000000001 RSI: ffffffff8e3d3fc0 RDI: ffffffff8c615f80
RBP: ffffed1003dde4b0 R08: 0000000000000001 R09: ffffed100d4a678d
R10: ffff88806a533c6b R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff9200002efc4 R15: dffffc0000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
 default_idle+0x9/0x10 arch/x86/kernel/process.c:768
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x3ae/0x5b0 kernel/sched/idle.c:355
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x158
 </TASK>
----------------
Code disassembly (best guess):
   0:	f8                   	clc
   1:	a2 02 e9 43 4f 03 00 	movabs %al,0x1f0f00034f43e902
   8:	0f 1f
   a:	00 90 90 90 90 90    	add    %dl,-0x6f6f6f70(%rax)
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	eb 07                	jmp    0x28
  21:	0f 00 2d 83 b0 24 00 	verw   0x24b083(%rip)        # 0x24b0ab
  28:	fb                   	sti
  29:	f4                   	hlt
* 2a:	c3                   	ret <-- trapping instruction
  2b:	cc                   	int3
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  36:	00 00 00
  39:	66 90                	xchg   %ax,%ax
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop