Re: BUG: unable to handle kernel paging request in csi_J

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit:    51d69817 Merge tag 'platform-drivers-x86-v5.5-3' of git://..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=145bfa59e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfbb8fa33f49f9f3
dashboard link: https://syzkaller.appspot.com/bug?extid=3f1750a5249afd5d7d2d
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/  
c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10d23421e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=166ef33ee00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3f1750a5249afd5d7d2d@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: unable to handle page fault for address: 000000010000000e
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 9e8e1067 P4D 9e8e1067 PUD 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8751 Comm: syz-executor043 Not tainted 5.5.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:memset16 arch/x86/include/asm/string_64.h:25 [inline]
RIP: 0010:scr_memsetw include/linux/vt_buffer.h:36 [inline]
RIP: 0010:csi_J+0x6c7/0xa80 drivers/tty/vt/vt.c:1529
Code: 3b 49 8d 9e c8 03 00 00 48 89 d8 48 c1 e8 03 42 8a 04 28 84 c0 0f 85  
53 01 00 00 0f b7 03 44 89 e1 81 e1 ff ff ff 7f 4c 89 ff <f3> 66 ab 48 c7  
c3 5c 8f 44 89 48 c7 c7 5c 8f 44 89 be 04 00 00 00
RSP: 0018:ffffc90001ee7830 EFLAGS: 00010202
RAX: 0000000000000720 RBX: ffff8880a7cb73c8 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000010000000e
RBP: ffffc90001ee7870 R08: ffffffff83f954a1 R09: ffffffff83f9522d
R10: ffff88808f1a81c0 R11: 0000000000000004 R12: 7fffffff80000001
R13: dffffc0000000000 R14: ffff8880a7cb7000 R15: 000000010000000e
FS:  00000000018af880(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000010000000e CR3: 00000000a3c14000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_con_trol drivers/tty/vt/vt.c:2367 [inline]
 do_con_write+0x7183/0xf360 drivers/tty/vt/vt.c:2797
 con_write+0x25/0x40 drivers/tty/vt/vt.c:3135
 process_output_block drivers/tty/n_tty.c:595 [inline]
 n_tty_write+0xd0c/0x1200 drivers/tty/n_tty.c:2333
 do_tty_write drivers/tty/tty_io.c:962 [inline]
 tty_write+0x5a1/0x950 drivers/tty/tty_io.c:1046
 __vfs_write+0xb8/0x740 fs/read_write.c:494
 vfs_write+0x270/0x580 fs/read_write.c:558
 ksys_write+0x117/0x220 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:620
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4404f9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe37f8e118 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004404f9
RDX: 0000000000000078 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401de0
R13: 0000000000401e70 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
CR2: 000000010000000e
---[ end trace 0426c9c4e025bc85 ]---
RIP: 0010:memset16 arch/x86/include/asm/string_64.h:25 [inline]
RIP: 0010:scr_memsetw include/linux/vt_buffer.h:36 [inline]
RIP: 0010:csi_J+0x6c7/0xa80 drivers/tty/vt/vt.c:1529
Code: 3b 49 8d 9e c8 03 00 00 48 89 d8 48 c1 e8 03 42 8a 04 28 84 c0 0f 85  
53 01 00 00 0f b7 03 44 89 e1 81 e1 ff ff ff 7f 4c 89 ff <f3> 66 ab 48 c7  
c3 5c 8f 44 89 48 c7 c7 5c 8f 44 89 be 04 00 00 00
RSP: 0018:ffffc90001ee7830 EFLAGS: 00010202
RAX: 0000000000000720 RBX: ffff8880a7cb73c8 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000010000000e
RBP: ffffc90001ee7870 R08: ffffffff83f954a1 R09: ffffffff83f9522d
R10: ffff88808f1a81c0 R11: 0000000000000004 R12: 7fffffff80000001
R13: dffffc0000000000 R14: ffff8880a7cb7000 R15: 000000010000000e
FS:  00000000018af880(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000010000000e CR3: 00000000a3c14000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400