=============================
[ BUG: Invalid wait context ]
syzkaller #0 Tainted: G             L     
-----------------------------
syz.2.735/8404 is trying to lock:
ffff88805a2752d0 (&gpc->lock){....}-{3:3}, at: kvm_xen_set_evtchn_fast+0x253/0xe80 arch/x86/kvm/xen.c:1819
other info that might help us debug this:
context-{2:2}
1 lock held by syz.2.735/8404:
 #0: ffff88805a275850 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
 #0: ffff88805a275850 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
 #0: ffff88805a275850 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_set_evtchn_fast+0x245/0xe80 arch/x86/kvm/xen.c:1817
stack backtrace:
CPU: 0 UID: 0 PID: 8404 Comm: syz.2.735 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:4830 [inline]
 check_wait_context kernel/locking/lockdep.c:4902 [inline]
 __lock_acquire+0xfa4/0x2630 kernel/locking/lockdep.c:5187
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
 _raw_read_lock_irqsave+0x46/0x90 kernel/locking/spinlock.c:240
 kvm_xen_set_evtchn_fast+0x253/0xe80 arch/x86/kvm/xen.c:1819
 xen_timer_callback+0x1db/0x2a0 arch/x86/kvm/xen.c:140
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x142/0xa00 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_is_held_type+0xf5/0x140 kernel/locking/lockdep.c:5945
Code: ff ff ff ff 65 0f c1 15 f1 b5 80 08 83 fa 01 8b 44 24 04 75 2d 9c 5a 80 e6 02 75 47 41 f7 c5 00 02 00 00 74 01 fb 48 83 c4 08 <5b> 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc e9 57 39 03 00 31 c0
RSP: 0018:ffffc90006fcfbb0 EFLAGS: 00000292
RAX: 0000000000000000 RBX: ffffffff8e7e5700 RCX: 0000000000000001
RDX: 0000000000000046 RSI: ffffffff8defc0c2 RDI: ffffffff8c1c3800
RBP: ffff888029cfca00 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff
R13: 0000000000000246 R14: 0000000000000000 R15: ffff888029cfca00
 lock_is_held include/linux/lockdep.h:249 [inline]
 __might_resched+0x248/0x330 kernel/sched/core.c:9125
 __might_fault+0x8b/0x140 mm/memory.c:7322
 _inline_copy_from_user include/linux/uaccess.h:169 [inline]
 _copy_from_user+0x29/0xd0 lib/usercopy.c:18
 copy_from_user include/linux/uaccess.h:223 [inline]
 restore_sigcontext+0xcd/0x6a0 arch/x86/kernel/signal_64.c:59
 __do_sys_rt_sigreturn+0x229/0x2c0 arch/x86/kernel/signal_64.c:268
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff55a73e1d9
Code: 11 06 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 0c 25
RSP: 002b:00007ffd91718380 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 000000000001ea35 RCX: 00007ff55a73e1d9
RDX: 00007ffd91718380 RSI: 00007ffd917184b0 RDI: 0000000000000011
RBP: 0000000000000032 R08: 0000000000000001 R09: 0000000000000000
R10: 00007ffd91719150 R11: 0000000000000246 R12: 00007ffd91719170
R13: 00007ff55aa15fac R14: 000000000001ea67 R15: 00007ffd91719150
 </TASK>
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	ff 65 0f             	jmp    *0xf(%rbp)
   3:	c1 15 f1 b5 80 08 83 	rcll   $0x83,0x880b5f1(%rip)        # 0x880b5fb
   a:	fa                   	cli
   b:	01 8b 44 24 04 75    	add    %ecx,0x75042444(%rbx)
  11:	2d 9c 5a 80 e6       	sub    $0xe6805a9c,%eax
  16:	02 75 47             	add    0x47(%rbp),%dh
  19:	41 f7 c5 00 02 00 00 	test   $0x200,%r13d
  20:	74 01                	je     0x23
  22:	fb                   	sti
  23:	48 83 c4 08          	add    $0x8,%rsp
* 27:	5b                   	pop    %rbx <-- trapping instruction
  28:	5d                   	pop    %rbp
  29:	41 5c                	pop    %r12
  2b:	41 5d                	pop    %r13
  2d:	41 5e                	pop    %r14
  2f:	41 5f                	pop    %r15
  31:	c3                   	ret
  32:	cc                   	int3
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	e9 57 39 03 00       	jmp    0x33992
  3b:	31 c0                	xor    %eax,%eax