general protection fault in cdev

general protection fault in cdev_del
Status: upstream: reported C repro on 2019/12/04 03:14
Reported-by: syzbot+3ed778aa210a888794e3@syzkaller.appspotmail.com
First crash: 461d, last: 2d14h

similar bugs (3):
Kernel	Title	Repro	Cause bisect	Count	Last	Reported	Patched	Status
upstream	general protection fault in cdev_del (2)	C	error	29	11d	165d	0/21	upstream: reported C repro on 2020/09/24 09:26
upstream	general protection fault in cdev_del	C		315	182d	650d	17/21	fixed on 2020/09/16 22:51
linux-4.19	general protection fault in cdev_del	C		144	3d15h	456d	0/1	upstream: reported C repro on 2019/12/09 03:59

Sample crash report:

RBP: 00007ffd5d7933d0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 7041 Comm: syz-executor468 Not tainted 4.14.157-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888093fd2140 task.stack: ffff88807b630000
RIP: 0010:cdev_del+0x28/0xa0 fs/char_dev.c:602
RSP: 0018:ffff88807b637b10 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: ffff888218e1e100 RCX: 0000000000000000
RDX: 000000000000000c RSI: ffff888093fd29e8 RDI: 0000000000000064
RBP: ffff88807b637b20 R08: ffff888093fd2140 R09: ffff888093fd2a08
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000008 R14: ffff888218e50ac8 R15: ffff888089959728
FS:  0000000000fee880(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f406a72c000 CR3: 00000000a680b000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tty_unregister_device drivers/tty/tty_io.c:3041 [inline]
 tty_unregister_device+0x106/0x1a0 drivers/tty/tty_io.c:3036
 gsmld_detach_gsm drivers/tty/n_gsm.c:2299 [inline]
 gsmld_close+0xb2/0x178 drivers/tty/n_gsm.c:2368
 tty_ldisc_close.isra.0+0x99/0xd0 drivers/tty/tty_ldisc.c:498
 tty_ldisc_kill+0x4b/0xc0 drivers/tty/tty_ldisc.c:644
 tty_ldisc_release+0xb6/0x230 drivers/tty/tty_ldisc.c:811
 tty_release_struct+0x1b/0x50 drivers/tty/tty_io.c:1603
 tty_release+0xaa3/0xd60 drivers/tty/tty_io.c:1776
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x7df/0x2ce0 kernel/exit.c:874
 do_group_exit+0x111/0x330 kernel/exit.c:977
 SYSC_exit_group kernel/exit.c:988 [inline]
 SyS_exit_group+0x1d/0x20 kernel/exit.c:986
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x43fdb8
RSP: 002b:00007ffd5d793378 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043fdb8
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004bfaf0 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000
Code: ff eb dd 55 48 89 e5 41 54 49 89 fc 48 83 ec 08 e8 8e ea cc ff 49 8d 7c 24 64 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 55 
RIP: cdev_del+0x28/0xa0 fs/char_dev.c:602 RSP: ffff88807b637b10
---[ end trace c6470828c66c35dc ]---

Crashes (185):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-linux-4-14	2019/12/04 02:46	linux-4.14.y	fbc5fe7a	0ecb9746	.config	log	report	syz	C
ci2-linux-4-14	2021/03/06 16:27	linux-4.14.y	397a88b2	e4b4d570	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/03/02 06:49	linux-4.14.y	3242aa3a	183afb6c	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/02/24 11:35	linux-4.14.y	3242aa3a	fcc6d71b	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/02/24 08:16	linux-4.14.y	3242aa3a	fcc6d71b	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/02/21 03:36	linux-4.14.y	29c52025	3e5ed8b4	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/02/20 02:24	linux-4.14.y	29c52025	f689d40a	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/02/11 02:44	linux-4.14.y	2c8a3fce	a52ee10a	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/02/05 02:37	linux-4.14.y	2c8a3fce	23a562df	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/02/04 14:11	linux-4.14.y	2c8a3fce	42b90a7c	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/02/01 21:42	linux-4.14.y	2c8a3fce	e6b95f32	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/01/30 19:31	linux-4.14.y	2c8a3fce	fc9fd31e	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/01/30 13:22	linux-4.14.y	2d2791fc	fc9fd31e	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/01/29 13:13	linux-4.14.y	2d2791fc	6593fd32	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/01/29 11:06	linux-4.14.y	2d2791fc	6593fd32	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/01/28 22:17	linux-4.14.y	2d2791fc	7df34f59	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/01/28 12:34	linux-4.14.y	2d2791fc	eefc07f2	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/01/25 11:36	linux-4.14.y	2d2791fc	52e37319	.config	log	report			info	general protection fault in cdev_del
ci2-linux-4-14	2021/01/15 01:27	linux-4.14.y	f79dc860	468dbb55	.config	log	report			info
ci2-linux-4-14	2021/01/14 23:27	linux-4.14.y	f79dc860	468dbb55	.config	log	report			info
ci2-linux-4-14	2021/01/10 00:52	linux-4.14.y	ec822b3e	2c1f2513	.config	log	report			info
ci2-linux-4-14	2021/01/07 05:54	linux-4.14.y	17529385	c104d4a3	.config	log	report			info
ci2-linux-4-14	2021/01/06 02:02	linux-4.14.y	17529385	b1c228e1	.config	log	report			info
ci2-linux-4-14	2021/01/05 16:50	linux-4.14.y	17529385	a0234d98	.config	log	report			info
ci2-linux-4-14	2020/12/31 10:47	linux-4.14.y	17529385	5cc121d6	.config	log	report			info
ci2-linux-4-14	2020/12/31 10:22	linux-4.14.y	17529385	5cc121d6	.config	log	report			info
ci2-linux-4-14	2020/12/26 14:42	linux-4.14.y	3f2ecb86	821e0b09	.config	log	report			info
ci2-linux-4-14	2020/12/25 23:07	linux-4.14.y	3f2ecb86	821e0b09	.config	log	report			info
ci2-linux-4-14	2020/12/18 12:24	linux-4.14.y	3f2ecb86	04201c06	.config	log	report			info
ci2-linux-4-14	2020/12/17 10:55	linux-4.14.y	3f2ecb86	04201c06	.config	log	report			info
ci2-linux-4-14	2020/12/16 12:54	linux-4.14.y	3f2ecb86	649595c6	.config	log	report			info
ci2-linux-4-14	2020/12/08 07:45	linux-4.14.y	c196b3a9	51a9082e	.config	log	report			info
ci2-linux-4-14	2020/12/07 12:18	linux-4.14.y	c196b3a9	f80ce148	.config	log	report			info
ci2-linux-4-14	2020/12/07 01:38	linux-4.14.y	c196b3a9	c521566d	.config	log	report			info
ci2-linux-4-14	2020/12/06 14:03	linux-4.14.y	c196b3a9	f12ba0c5	.config	log	report			info
ci2-linux-4-14	2020/12/06 04:39	linux-4.14.y	c196b3a9	50503117	.config	log	report			info
ci2-linux-4-14	2020/12/05 09:50	linux-4.14.y	c196b3a9	0ef84591	.config	log	report			info
ci2-linux-4-14	2020/12/02 22:47	linux-4.14.y	c196b3a9	eff43e99	.config	log	report			info
ci2-linux-4-14	2020/11/25 23:47	linux-4.14.y	87335852	3f581b43	.config	log	report			info
ci2-linux-4-14	2020/11/25 08:03	linux-4.14.y	87335852	1a1f4bd8	.config	log	report			info
ci2-linux-4-14	2020/11/22 21:06	linux-4.14.y	0df445b0	0d27f508	.config	log	report			info
ci2-linux-4-14	2020/11/21 07:50	linux-4.14.y	8961076e	68068804	.config	log	report			info
ci2-linux-4-14	2020/11/19 03:09	linux-4.14.y	8961076e	0767f13f	.config	log	report			info
ci2-linux-4-14	2020/11/19 00:56	linux-4.14.y	8961076e	0767f13f	.config	log	report			info
ci2-linux-4-14	2020/11/17 05:13	linux-4.14.y	27ce4f2a	1bf9a662	.config	log	report			info
ci2-linux-4-14	2020/11/16 13:27	linux-4.14.y	27ce4f2a	1bf9a662	.config	log	report			info
ci2-linux-4-14	2020/11/07 06:31	linux-4.14.y	6b6446ef	cba33199	.config	log	report			info
ci2-linux-4-14	2020/11/04 02:01	linux-4.14.y	2b791501	cba33199	.config	log	report			info