BUG: unable to handle kernel paging request in do_con

BUG: unable to handle kernel paging request in do_con_trol
Status: upstream: reported C repro on 2019/12/09 17:13
Reported-by: syzbot+b278b6a526f6a5af5fc6@syzkaller.appspotmail.com
First crash: 450d, last: 279d

Fix bisection: the fix commit could be any of (bisect log):
a844dc4c5442 Linux 4.14.158
4139fb08c05f Linux 4.14.187

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.19	BUG: unable to handle kernel paging request in do_con_trol	C		done	36	218d	450d	1/1	fixed on 2020/08/28 16:06
upstream	BUG: unable to handle kernel paging request in do_con_trol	C	done		98	252d	450d	0/21	closed as dup on 2020/07/20 22:52

Sample crash report:

audit: type=1400 audit(1575911417.577:36): avc:  denied  { map } for  pid=6980 comm="syz-executor237" path="/root/syz-executor237277072" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
BUG: unable to handle kernel paging request at 000000010000000e
IP: memset16 arch/x86/include/asm/string_64.h:58 [inline]
IP: scr_memsetw include/linux/vt_buffer.h:36 [inline]
IP: csi_K drivers/tty/vt/vt.c:1222 [inline]
IP: do_con_trol+0x2fac/0x5b40 drivers/tty/vt/vt.c:2013
PGD 8ea9a067 P4D 8ea9a067 PUD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 6980 Comm: syz-executor237 Not tainted 4.14.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880a950c300 task.stack: ffff888098ec0000
RIP: 0010:memset16 arch/x86/include/asm/string_64.h:58 [inline]
RIP: 0010:scr_memsetw include/linux/vt_buffer.h:36 [inline]
RIP: 0010:csi_K drivers/tty/vt/vt.c:1222 [inline]
RIP: 0010:do_con_trol+0x2fac/0x5b40 drivers/tty/vt/vt.c:2013
RSP: 0018:ffff888098ec7878 EFLAGS: 00010202
RAX: 0000000000000720 RBX: 1ffff110131d8f13 RCX: 0000000000000001
RDX: 1ffff110100fbe51 RSI: 1ffff110100fbe67 RDI: 000000010000000e
RBP: ffff888098ec7960 R08: ffff8880807df28c R09: 0000000000000002
R10: 0000000000000000 R11: ffff8880a950c300 R12: ffff8880807deec0
R13: 0000000000000001 R14: 000000010000000e R15: 0000000000000002
FS:  0000000000e53880(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000010000000e CR3: 00000000a4870000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_con_write.part.0+0xcc7/0x1b50 drivers/tty/vt/vt.c:2434
 do_con_write drivers/tty/vt/vt.c:2205 [inline]
 con_write+0x38/0xc0 drivers/tty/vt/vt.c:2787
 process_output_block drivers/tty/n_tty.c:595 [inline]
 n_tty_write+0x38b/0xee0 drivers/tty/n_tty.c:2333
 do_tty_write drivers/tty/tty_io.c:959 [inline]
 tty_write+0x3f6/0x700 drivers/tty/tty_io.c:1043
 __vfs_write+0x105/0x6b0 fs/read_write.c:480
 vfs_write+0x198/0x500 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xfd/0x230 fs/read_write.c:582
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4404f9
RSP: 002b:00007ffed2974698 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004404f9
RDX: 0000000000000078 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401de0
R13: 0000000000401e70 R14: 0000000000000000 R15: 0000000000000000
Code: c1 e0 2a 48 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 2c 01 0f 8e e4 29 00 00 41 0f b7 84 24 c8 03 00 00 44 89 f9 4c 89 f7 d1 e9 <f3> 66 ab 49 8d bc 24 78 04 00 00 b8 ff ff 37 00 48 89 fa 48 c1 
RIP: memset16 arch/x86/include/asm/string_64.h:58 [inline] RSP: ffff888098ec7878
RIP: scr_memsetw include/linux/vt_buffer.h:36 [inline] RSP: ffff888098ec7878
RIP: csi_K drivers/tty/vt/vt.c:1222 [inline] RSP: ffff888098ec7878
RIP: do_con_trol+0x2fac/0x5b40 drivers/tty/vt/vt.c:2013 RSP: ffff888098ec7878
CR2: 000000010000000e
---[ end trace 9ed48a5e027adfcd ]---

Crashes (29):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci2-linux-4-14	2019/12/09 17:12	linux-4.14.y	a844dc4c	b31eda3d	.config	log	report	syz	C
ci2-linux-4-14	2020/05/28 01:38	linux-4.14.y	4f68020f	9072c126	.config	log	report
ci2-linux-4-14	2020/05/27 16:10	linux-4.14.y	4f68020f	9072c126	.config	log	report
ci2-linux-4-14	2020/05/13 11:43	linux-4.14.y	ab9dfda2	9a6d42fb	.config	log	report
ci2-linux-4-14	2020/05/11 20:10	linux-4.14.y	ab9dfda2	9eb09c40	.config	log	report
ci2-linux-4-14	2020/05/11 13:54	linux-4.14.y	ab9dfda2	f8f57555	.config	log	report
ci2-linux-4-14	2020/05/11 06:06	linux-4.14.y	ab9dfda2	8742a2b9	.config	log	report
ci2-linux-4-14	2020/05/05 18:53	linux-4.14.y	d71f695c	4b76dd25	.config	log	report
ci2-linux-4-14	2020/02/23 22:22	linux-4.14.y	98db2bf2	d801cb02	.config	log	report
ci2-linux-4-14	2020/02/23 12:35	linux-4.14.y	98db2bf2	2c36e7a7	.config	log	report
ci2-linux-4-14	2020/02/19 02:27	linux-4.14.y	98db2bf2	135c18aa	.config	log	report
ci2-linux-4-14	2020/02/19 01:01	linux-4.14.y	98db2bf2	135c18aa	.config	log	report
ci2-linux-4-14	2020/02/12 17:33	linux-4.14.y	e0f8b8a6	84f4fc8a	.config	log	report
ci2-linux-4-14	2020/02/09 05:42	linux-4.14.y	e0f8b8a6	06150bf1	.config	log	report
ci2-linux-4-14	2020/02/01 22:41	linux-4.14.y	9fa690a2	2274ad39	.config	log	report
ci2-linux-4-14	2020/01/28 04:44	linux-4.14.y	9a95f252	56cd6c9b	.config	log	report
ci2-linux-4-14	2020/01/25 08:16	linux-4.14.y	8bac5040	2e95ab33	.config	log	report
ci2-linux-4-14	2020/01/23 15:47	linux-4.14.y	8bac5040	11ebf937	.config	log	report
ci2-linux-4-14	2020/01/23 15:10	linux-4.14.y	8bac5040	11ebf937	.config	log	report
ci2-linux-4-14	2020/01/15 16:33	linux-4.14.y	c04fc6fa	069a5a44	.config	log	report
ci2-linux-4-14	2020/01/15 15:34	linux-4.14.y	c04fc6fa	069a5a44	.config	log	report
ci2-linux-4-14	2020/01/13 12:12	linux-4.14.y	6d0c334a	99565c1a	.config	log	report
ci2-linux-4-14	2020/01/12 13:03	linux-4.14.y	6d0c334a	31290a45	.config	log	report
ci2-linux-4-14	2020/01/10 15:51	linux-4.14.y	b0cdffaa	532ec44e	.config	log	report
ci2-linux-4-14	2020/01/10 14:37	linux-4.14.y	b0cdffaa	532ec44e	.config	log	report
ci2-linux-4-14	2020/01/09 04:04	linux-4.14.y	84f5ad46	ddc3e859	.config	log	report
ci2-linux-4-14	2020/01/08 10:30	linux-4.14.y	84f5ad46	ddc3e859	.config	log	report
ci2-linux-4-14	2019/12/30 16:42	linux-4.14.y	e1f7d50a	6b36d338	.config	log	report
ci2-linux-4-14	2019/12/13 06:42	linux-4.14.y	a844dc4c	2a752b7c	.config	log	report