Message-ID: <00000000000005d2bf059c3b86ac@google.com>
Date:   Wed, 15 Jan 2020 21:59:09 -0800
From:   syzbot <syzbot+d8cbeb7028cd2950172e@...kaller.appspotmail.com>
To:     daniel.vetter@...ll.ch, ghalat@...hat.com,
        gregkh@...uxfoundation.org, jslaby@...e.com,
        linux-kernel@...r.kernel.org, nico@...xnic.net, sam@...nborg.org,
        syzkaller-bugs@...glegroups.com, textshell@...uujin.de
Subject: BUG: unable to handle kernel paging request in do_con_write

Hello,

syzbot found 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=15a41c76e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfbb8fa33f49f9f3
dashboard link: https://syzkaller.appspot.com/bug?extid=d8cbeb7028cd2950172e
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/  
c2443155a0fb245c8f17f2c1c72b6ea391e86e81)

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+d8cbeb7028cd2950172e@...kaller.appspotmail.com

BUG: unable to handle page fault for address: ffffffff0000000e
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 9070067 P4D 9070067 PUD 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 25087 Comm: syz-executor.4 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:delete_char drivers/tty/vt/vt.c:853 [inline]
RIP: 0010:csi_P drivers/tty/vt/vt.c:1985 [inline]
RIP: 0010:do_con_trol drivers/tty/vt/vt.c:2379 [inline]
RIP: 0010:do_con_write+0x9565/0xf360 drivers/tty/vt/vt.c:2797
Code: 00 00 00 00 fc ff df 8a 04 08 84 c0 0f 85 60 4b 00 00 48 8b 84 24 a0  
00 00 00 0f b7 00 41 81 e4 ff ff ff 7f 4c 89 e1 48 89 df <f3> 66 ab 48 b8  
00 00 00 00 00 fc ff df 48 8b 4c 24 50 8a 04 01 84
RSP: 0018:ffffc900019e7880 EFLAGS: 00010202
RAX: 0000000000000720 RBX: ffffffff0000000e RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000100000010 RDI: ffffffff0000000e
RBP: ffffc900019e7b68 R08: ffffffff83fa0511 R09: ffffffff83f9de70
R10: ffff8880a14b0180 R11: 000000000000001c R12: 0000000000000001
R13: 0000000000000000 R14: 0000000100000010 R15: 0000000000000002
FS:  00007f9510ce8700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff0000000e CR3: 000000009570c000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  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: 0033:0x45aff9
Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9510ce7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f9510ce86d4 RCX: 000000000045aff9
RDX: 0000000000000320 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000c60 R14: 00000000004cd0b9 R15: 000000000075bf2c
Modules linked in:
CR2: ffffffff0000000e
---[ end trace 0cf51c4bf0974ba5 ]---
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:delete_char drivers/tty/vt/vt.c:853 [inline]
RIP: 0010:csi_P drivers/tty/vt/vt.c:1985 [inline]
RIP: 0010:do_con_trol drivers/tty/vt/vt.c:2379 [inline]
RIP: 0010:do_con_write+0x9565/0xf360 drivers/tty/vt/vt.c:2797
Code: 00 00 00 00 fc ff df 8a 04 08 84 c0 0f 85 60 4b 00 00 48 8b 84 24 a0  
00 00 00 0f b7 00 41 81 e4 ff ff ff 7f 4c 89 e1 48 89 df <f3> 66 ab 48 b8  
00 00 00 00 00 fc ff df 48 8b 4c 24 50 8a 04 01 84
RSP: 0018:ffffc900019e7880 EFLAGS: 00010202
RAX: 0000000000000720 RBX: ffffffff0000000e RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000100000010 RDI: ffffffff0000000e
RBP: ffffc900019e7b68 R08: ffffffff83fa0511 R09: ffffffff83f9de70
R10: ffff8880a14b0180 R11: 000000000000001c R12: 0000000000000001
R13: 0000000000000000 R14: 0000000100000010 R15: 0000000000000002
FS:  00007f9510ce8700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff0000000e CR3: 000000009570c000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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