BUG: unable to handle kernel paging request in vga16fb_fillrect

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fcfbdfe9626e Linux 4.19.197
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=134b4812300000
kernel config: https://syzkaller.appspot.com/x/.config?x=2dedd11d3941c171
dashboard link: https://syzkaller.appspot.com/bug?extid=82d6cf6b35b53ecd1b0d
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17fa9a24300000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145d0f80300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+82d6cf...@syzkaller.appspotmail.com

BUG: unable to handle kernel paging request at ffff888001000050
PGD de01067 P4D de01067 PUD de02067 PMD 80000000010001e1
Oops: 0003 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8109 Comm: syz-executor431 Not tainted 4.19.197-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline]
RIP: 0010:vga16fb_fillrect+0x9c0/0x1940 drivers/video/fbdev/vga16fb.c:923
Code: c3 fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 c7 d0 c3 fd 31 ff 89 de 31 ed e8 2c d2 c3 fd 85 db 4d 89 ec 74 22 e8 b0 d0 c3 fd <45> 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 8c d1 c3 fd 39 eb
RSP: 0018:ffff88808f32f2c0 EFLAGS: 00010293
RAX: ffff888095e283c0 RBX: 000000000000001b RCX: ffffffff839eaf34
RDX: 0000000000000000 RSI: ffffffff839eaf40 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: ffff888001000050
R13: ffff888001000050 R14: 0000000000000000 R15: 000000000ffeb7ff
FS: 0000000002394300(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888001000050 CR3: 00000000ab91e000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
bit_clear_margins+0x3f6/0x4b0 drivers/video/fbdev/core/bitblit.c:224
fbcon_clear_margins+0x1e2/0x350 drivers/video/fbdev/core/fbcon.c:1288
fbcon_switch+0xf0d/0x1ba0 drivers/video/fbdev/core/fbcon.c:2155
redraw_screen+0x37d/0x870 drivers/tty/vt/vt.c:1015
fbcon_modechanged+0x6df/0x930 drivers/video/fbdev/core/fbcon.c:2688
fbcon_event_notify+0x197/0x1d80 drivers/video/fbdev/core/fbcon.c:3061
notifier_call_chain+0xc0/0x230 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+0x85/0xa0 kernel/notifier.c:325
fb_set_var+0xc51/0xe20 drivers/video/fbdev/core/fbmem.c:1042
do_fb_ioctl+0x3cf/0xb50 drivers/video/fbdev/core/fbmem.c:1115
fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1230
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/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: 0033:0x43efd9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff7797a908 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043efd9
RDX: 0000000020000200 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 0000000000402fc0 R08: 0000000000000000 R09: 0000000000400488
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000403050
R13: 0000000000000000 R14: 00000000004ac018 R15: 0000000000400488
Modules linked in:
CR2: ffff888001000050
---[ end trace b8a931742cb6e79d ]---
RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline]
RIP: 0010:vga16fb_fillrect+0x9c0/0x1940 drivers/video/fbdev/vga16fb.c:923
Code: c3 fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 c7 d0 c3 fd 31 ff 89 de 31 ed e8 2c d2 c3 fd 85 db 4d 89 ec 74 22 e8 b0 d0 c3 fd <45> 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 8c d1 c3 fd 39 eb
RSP: 0018:ffff88808f32f2c0 EFLAGS: 00010293
RAX: ffff888095e283c0 RBX: 000000000000001b RCX: ffffffff839eaf34
RDX: 0000000000000000 RSI: ffffffff839eaf40 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: ffff888001000050
R13: ffff888001000050 R14: 0000000000000000 R15: 000000000ffeb7ff
FS: 0000000002394300(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888001000050 CR3: 00000000ab91e000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches