BUG: unable to handle kernel paging request in sys_imageblit

[syzbot <syzbot+33f89a9a6b6acd893b11@syzkaller.appspotmail.com>]

Hello,

syzbot found the following crash on:

HEAD commit:    6794862a Merge tag 'for-5.5-rc1-kconfig-tag' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x\x1574aaeae00000
kernel config:  https://syzkaller.appspot.com/x/.config?xyf79de2a27d3e3d
dashboard link: https://syzkaller.appspot.com/bug?extid3f89a9a6b6acd893b11
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+33f89a9a6b6acd893b11@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: fffff5200124c3fc
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 7ffcd067 P4D 7ffcd067 PUD 2cd1c067 PMD 299b2067 PTE 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 2 PID: 9109 Comm: syz-executor.2 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS  
rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline]
RIP: 0010:sys_imageblit+0x61c/0x1240  
drivers/video/fbdev/core/sysimgblt.c:275
Code: 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 57 0b 00 00 48 b9 00 00 00 00 00  
fc ff df 4c 89 fa 8b 45 b0 23 07 4d 8d 77 04 48 c1 ea 03 <0f> b6 0c 0a 4c  
89 fa 83 e2 07 33 45 c4 83 c2 03 38 ca 7c 08 84 c9
RSP: 0018:ffffc900042c7168 EFLAGS: 00010a06
RAX: 0000000000000000 RBX: ffff888076970800 RCX: dffffc0000000000
RDX: 1ffff9200124c3fc RSI: ffffffff83b4fada RDI: ffffffff887498e0
RBP: ffffc900042c7230 R08: ffff88805d278e40 R09: 000000000000007f
R10: fffffbfff14f3347 R11: ffffffff8a799a3b R12: 0000000000000007
R13: 0000000000000007 R14: ffffc90009261fe4 R15: ffffc90009261fe0
FS:  00007f0af02fc700(0000) GS:ffff88802d200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff5200124c3fc CR3: 00000000278c2000 CR4: 0000000000340ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  drm_fb_helper_sys_imageblit+0x21/0x180 drivers/gpu/drm/drm_fb_helper.c:768
  bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:139 [inline]
  bit_putcs+0x9a3/0xf10 drivers/video/fbdev/core/bitblit.c:188
  fbcon_putcs+0x33c/0x3e0 drivers/video/fbdev/core/fbcon.c:1353
  do_update_region+0x42b/0x6f0 drivers/tty/vt/vt.c:677
  invert_screen+0x2da/0x650 drivers/tty/vt/vt.c:794
  highlight drivers/tty/vt/selection.c:53 [inline]
  clear_selection drivers/tty/vt/selection.c:81 [inline]
  clear_selection+0x59/0x70 drivers/tty/vt/selection.c:77
  vc_do_resize+0x1163/0x1460 drivers/tty/vt/vt.c:1200
  vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1304
  fbcon_do_set_font+0x4a6/0x960 drivers/video/fbdev/core/fbcon.c:2599
  fbcon_set_font+0x72e/0x860 drivers/video/fbdev/core/fbcon.c:2696
  con_font_set drivers/tty/vt/vt.c:4538 [inline]
  con_font_op+0xe30/0x1270 drivers/tty/vt/vt.c:4603
  vt_ioctl+0xd2e/0x26d0 drivers/tty/vt/vt_ioctl.c:913
  tty_ioctl+0xa37/0x14f0 drivers/tty/tty_io.c:2660
  vfs_ioctl fs/ioctl.c:47 [inline]
  file_ioctl fs/ioctl.c:545 [inline]
  do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732
  ksys_ioctl+0xab/0xd0 fs/ioctl.c:749
  __do_sys_ioctl fs/ioctl.c:756 [inline]
  __se_sys_ioctl fs/ioctl.c:754 [inline]
  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
  do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a7c9
Code: bd b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 8b b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0af02fbc88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000072bf00 RCX: 000000000045a7c9
RDX: 0000000020000000 RSI: 0000000000004b61 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0af02fc6d4
R13: 00000000004ab60f R14: 00000000006ede60 R15: 00000000ffffffff
Modules linked in:
CR2: fffff5200124c3fc
---[ end trace 7698227ca2d5f789 ]---
RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline]
RIP: 0010:sys_imageblit+0x61c/0x1240  
drivers/video/fbdev/core/sysimgblt.c:275
Code: 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 57 0b 00 00 48 b9 00 00 00 00 00  
fc ff df 4c 89 fa 8b 45 b0 23 07 4d 8d 77 04 48 c1 ea 03 <0f> b6 0c 0a 4c  
89 fa 83 e2 07 33 45 c4 83 c2 03 38 ca 7c 08 84 c9
RSP: 0018:ffffc900042c7168 EFLAGS: 00010a06
RAX: 0000000000000000 RBX: ffff888076970800 RCX: dffffc0000000000
RDX: 1ffff9200124c3fc RSI: ffffffff83b4fada RDI: ffffffff887498e0
RBP: ffffc900042c7230 R08: ffff88805d278e40 R09: 000000000000007f
R10: fffffbfff14f3347 R11: ffffffff8a799a3b R12: 0000000000000007
R13: 0000000000000007 R14: ffffc90009261fe4 R15: ffffc90009261fe0
FS:  00007f0af02fc700(0000) GS:ffff88802d200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff5200124c3fc CR3: 00000000278c2000 CR4: 0000000000340ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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