general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
CPU: 0 PID: 31780 Comm: syz-executor.1 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:cdev_del+0x21/0x90 fs/char_dev.c:596
Code: 2e 0f 1f 84 00 00 00 00 00 55 41 56 53 48 89 fb 49 be 00 00 00 00 00 fc ff df e8 ca 80 b5 ff 48 8d 7b 60 48 89 f8 48 c1 e8 03 <42> 8a 04 30 84 c0 75 33 8b 6b 60 48 8d 7b 64 48 89 f8 48 c1 e8 03
RSP: 0018:ffffc9001977fc28 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000000 RCX: 0000000000040000
RDX: ffffc9000ab6a000 RSI: 0000000000002d8d RDI: 0000000000000060
RBP: 0000000000000008 R08: ffffffff83fb92bc R09: fffffbfff167ccb1
R10: fffffbfff167ccb1 R11: 0000000000000000 R12: ffff8880a1fab408
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff110143f5681
FS:  00007f0ff4fe9700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f53185a2db8 CR3: 000000001a7c3000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tty_unregister_device+0xed/0x170 drivers/tty/tty_io.c:3193
 gsmld_detach_gsm drivers/tty/n_gsm.c:2411 [inline]
 gsmld_close+0xa0/0x1e0 drivers/tty/n_gsm.c:2480
 tty_ldisc_kill drivers/tty/tty_ldisc.c:637 [inline]
 tty_ldisc_hangup+0x40b/0x660 drivers/tty/tty_ldisc.c:756
 __tty_hangup+0x4b4/0x740 drivers/tty/tty_io.c:625
 tty_release+0x378/0xf90 drivers/tty/tty_io.c:1679
 __fput+0x34f/0x7b0 fs/file_table.c:281
 task_work_run+0x137/0x1c0 kernel/task_work.c:135
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:139 [inline]
 exit_to_user_mode_prepare+0xfa/0x1c0 kernel/entry/common.c:166
 syscall_exit_to_user_mode+0x5e/0x1a0 kernel/entry/common.c:241
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ce69
Code: 2d 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0ff4fe8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000124
RAX: 0000000000000003 RBX: 0000000000002a00 RCX: 000000000045ce69
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000005
RBP: 000000000118c000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bfcc
R13: 00007ffe48c8a69f R14: 00007f0ff4fe99c0 R15: 000000000118bfcc
Modules linked in:
---[ end trace 630abedb1bcb769d ]---
RIP: 0010:cdev_del+0x21/0x90 fs/char_dev.c:596
Code: 2e 0f 1f 84 00 00 00 00 00 55 41 56 53 48 89 fb 49 be 00 00 00 00 00 fc ff df e8 ca 80 b5 ff 48 8d 7b 60 48 89 f8 48 c1 e8 03 <42> 8a 04 30 84 c0 75 33 8b 6b 60 48 8d 7b 64 48 89 f8 48 c1 e8 03
RSP: 0018:ffffc9001977fc28 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000000 RCX: 0000000000040000
RDX: ffffc9000ab6a000 RSI: 0000000000002d8d RDI: 0000000000000060
RBP: 0000000000000008 R08: ffffffff83fb92bc R09: fffffbfff167ccb1
R10: fffffbfff167ccb1 R11: 0000000000000000 R12: ffff8880a1fab408
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff110143f5681
FS:  00007f0ff4fe9700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f796ec34008 CR3: 000000001a7c3000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400