general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 30887 Comm: syz-executor.4 Not tainted 5.8.0-rc5-next-20200716-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__switch_to_asm+0x0/0x40 arch/x86/entry/entry_64.S:229
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0018:ffffc900182f73d8 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff8880ae635e18 RCX: 0000000000000000
RDX: 1ffff11015cc6bc2 RSI: ffff888055efa0c0 RDI: ffff88809da8c280
RBP: ffffc900182f74a8 R08: 0000000000000001 R09: ffff88809da8cb50
R10: fffffbfff1571bb9 R11: 0000000000000000 R12: ffff8880ae635e00
R13: ffff88809da8c280 R14: ffff888055efa0c0 R15: ffff88809da8c6b0
FS:  00007f49184d9700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0000d4000 CR3: 0000000055ebe000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 context_switch kernel/sched/core.c:3445 [inline]
 __schedule+0x8b4/0x1e80 kernel/sched/core.c:4169
 preempt_schedule_irq+0xb0/0x150 kernel/sched/core.c:4427
 idtentry_exit_cond_resched arch/x86/entry/common.c:663 [inline]
 idtentry_exit_cond_rcu+0xc0/0xf0 arch/x86/entry/common.c:710
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587
RIP: 0010:__sanitizer_cov_trace_pc+0x55/0x60 kernel/kcov.c:207
Code: 82 e8 13 00 00 83 f8 02 75 20 48 8b 8a f0 13 00 00 8b 92 ec 13 00 00 48 8b 01 48 83 c0 01 48 39 c2 76 07 48 89 34 c1 48 89 01 <c3> 66 2e 0f 1f 84 00 00 00 00 00 41 55 41 54 49 89 fc 55 48 bd eb
RSP: 0018:ffffc900182f75a8 EFLAGS: 00000246
RAX: 0000000000040000 RBX: 000000001fffffb0 RCX: ffffc90011973000
RDX: 0000000000040000 RSI: ffffffff83c86f50 RDI: 0000000000000004
RBP: 0000000000f69c88 R08: 0000000000000001 R09: ffff8880a3fb081f
R10: 000000001fffffb0 R11: 0000000000000000 R12: ffff888001009cd8
R13: ffff8880000a0050 R14: 0000000000000000 R15: 00000000000000ef
 writeb arch/x86/include/asm/io.h:65 [inline]
 vga16fb_fillrect+0x9c0/0x193b drivers/video/fbdev/vga16fb.c:923
 bit_clear_margins+0x3f6/0x4a0 drivers/video/fbdev/core/bitblit.c:224
 fbcon_clear_margins+0x1d5/0x230 drivers/video/fbdev/core/fbcon.c:1381
 fbcon_switch+0xb6f/0x16c0 drivers/video/fbdev/core/fbcon.c:2363
 redraw_screen+0x2af/0x770 drivers/tty/vt/vt.c:1020
 fbcon_modechanged+0x575/0x710 drivers/video/fbdev/core/fbcon.c:3001
 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:3048
 fb_set_var+0xae8/0xd60 drivers/video/fbdev/core/fbmem.c:1056
 do_fb_ioctl+0x33f/0x6c0 drivers/video/fbdev/core/fbmem.c:1109
 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:753
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl fs/ioctl.c:760 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c1d9
Code: Bad RIP value.
RSP: 002b:00007f49184d8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000000ce80 RCX: 000000000045c1d9
RDX: 0000000020000200 RSI: 0000000000004601 RDI: 0000000000000005
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007fff24c8261f R14: 00007f49184d99c0 R15: 000000000078bf0c
Modules linked in:
---[ end trace c8b56115e2b4f95d ]---
RIP: 0010:__switch_to_asm+0x0/0x40 arch/x86/entry/entry_64.S:229
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 0018:ffffc900182f73d8 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff8880ae635e18 RCX: 0000000000000000
RDX: 1ffff11015cc6bc2 RSI: ffff888055efa0c0 RDI: ffff88809da8c280
RBP: ffffc900182f74a8 R08: 0000000000000001 R09: ffff88809da8cb50
R10: fffffbfff1571bb9 R11: 0000000000000000 R12: ffff8880ae635e00
R13: ffff88809da8c280 R14: ffff888055efa0c0 R15: ffff88809da8c6b0
FS:  00007f49184d9700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0000d4000 CR3: 0000000055ebe000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400