INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 4749 Comm: syz-executor.5 Not tainted 4.14.172-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:17 [inline]
 dump_stack+0x13e/0x194 lib/dump_stack.c:58
 register_lock_class+0x2fe/0x1600 kernel/locking/lockdep.c:768
 __lock_acquire+0x147/0x4620 kernel/locking/lockdep.c:3374
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:160
 try_to_wake_up+0x6a/0xef0 kernel/sched/core.c:1997
 hrtimer_wakeup+0x43/0x60 kernel/time/hrtimer.c:1441
 __run_hrtimer kernel/time/hrtimer.c:1223 [inline]
 __hrtimer_run_queues+0x25c/0xbb0 kernel/time/hrtimer.c:1287
 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1075 [inline]
 smp_apic_timer_interrupt+0x117/0x5e0 arch/x86/kernel/apic/apic.c:1100
 apic_timer_interrupt+0x8f/0xa0 arch/x86/entry/entry_64.S:792
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x3d/0x50 kernel/kcov.c:87
RSP: 0018:ffff88821334f3c8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
RAX: 0000000000040000 RBX: ffff8880200a0000 RCX: ffffc90005e3c000
RDX: 000000000003ffff RSI: ffffffff831e5da3 RDI: ffff88821334f480
RBP: 000000001fffffb0 R08: 000000000000ffff R09: ffffed1014b2b2b4
R10: ffffed1014b2b2b3 R11: ffff8880a595959f R12: ffff888000128987
R13: 0000000000000000 R14: 000000000000000f R15: 000000001fffffaf
 writeb arch/x86/include/asm/io.h:65 [inline]
 vga16fb_fillrect+0x943/0x1880 drivers/video/fbdev/vga16fb.c:923
 bit_clear_margins+0x3af/0x480 drivers/video/fbdev/core/bitblit.c:224
 fbcon_clear_margins+0x285/0x310 drivers/video/fbdev/core/fbcon.c:1317
 fbcon_switch+0xcdf/0x1780 drivers/video/fbdev/core/fbcon.c:2299
 redraw_screen+0x331/0x770 drivers/tty/vt/vt.c:688
 fbcon_modechanged+0x59d/0x890 drivers/video/fbdev/core/fbcon.c:2946
 fbcon_event_notify+0x11a/0x1746 drivers/video/fbdev/core/fbcon.c:3299
 notifier_call_chain+0x107/0x1a0 kernel/notifier.c:93
 __blocking_notifier_call_chain kernel/notifier.c:317 [inline]
 __blocking_notifier_call_chain kernel/notifier.c:304 [inline]
 blocking_notifier_call_chain kernel/notifier.c:328 [inline]
 blocking_notifier_call_chain+0x79/0x90 kernel/notifier.c:325
 fb_set_var+0xaad/0xc70 drivers/video/fbdev/core/fbmem.c:1054
 do_fb_ioctl+0x3cc/0x940 drivers/video/fbdev/core/fbmem.c:1127
 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1242
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c479
RSP: 002b:00007fda09337c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fda093386d4 RCX: 000000000045c479
RDX: 0000000020000340 RSI: 0000000000004601 RDI: 0000000000000004
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000002ef R14: 00000000004c5096 R15: 000000000076bf2c
BUG: unable to handle kernel paging request at ffffffffffffff74
IP: wait_consider_task+0x99/0x3030 kernel/exit.c:1329
PGD 7c6d067 P4D 7c6d067 PUD 7c6f067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 7482 Comm: syz-executor.5 Not tainted 4.14.172-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880983c2180 task.stack: ffff888090eb8000
RIP: 0010:wait_consider_task+0x99/0x3030 kernel/exit.c:1329
RSP: 0018:ffff888090ebfb30 EFLAGS: 00010246
RAX: 0000000000000007 RBX: 0000000000000000 RCX: ffffffffffffff74
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888090ebfd08
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 1ffff110121d7ff9 R11: ffff8880983c2180 R12: ffff888090ebfd08
R13: fffffffffffffaf8 R14: fffffffffffffaf8 R15: ffff888090ebfd08
FS:  0000000001c72940(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffff74 CR3: 00000000809bd000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_wait_thread kernel/exit.c:1438 [inline]
 do_wait+0x3e9/0x930 kernel/exit.c:1509
 kernel_wait4+0x103/0x1e0 kernel/exit.c:1652
 SYSC_wait4+0x106/0x110 kernel/exit.c:1664
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4162ba
RSP: 002b:00007ffcd3dc0a98 EFLAGS: 00000246 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 00000000001970d4 RCX: 00000000004162ba
RDX: 0000000040000001 RSI: 00007ffcd3dc0ad0 RDI: ffffffffffffffff
RBP: 0000000000001c6b R08: 0000000000000001 R09: 0000000001c72940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffcd3dc0ad0 R14: 00000000001970a5 R15: 00007ffcd3dc0ae0
Code: 8d 8e 7c 04 00 00 48 89 c8 48 89 4c 24 08 48 c1 e8 03 0f b6 14 28 48 89 c8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 e6 14 00 00 <41> 8b ae 7c 04 00 00 83 fd 10 0f 84 a1 00 00 00 e8 d2 af 23 00 
RIP: wait_consider_task+0x99/0x3030 kernel/exit.c:1329 RSP: ffff888090ebfb30
CR2: ffffffffffffff74
---[ end trace 5eca494db5e7b1bc ]---