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: 25340 Comm: syz-executor.0 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:ffffc90019c5fc28 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000000 RCX: ffff88801b910000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000060
RBP: 0000000000000008 R08: ffffffff83fac4ec R09: fffffbfff167c6b1
R10: fffffbfff167c6b1 R11: 0000000000000000 R12: ffff8882185c3d08
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff110430b87a1
FS:  00000000017a5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2eb22000 CR3: 0000000218a8e000 CR4: 00000000001526f0
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: 0033:0x416981
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffcd2d3b650 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000416981
RDX: 0000000000000000 RSI: 00000000000007b6 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00000000f48f87b6 R09: 00000000f48f87ba
R10: 00007ffcd2d3b740 R11: 0000000000000293 R12: 000000000118c920
R13: 000000000118c920 R14: ffffffffffffffff R15: 000000000118bf2c
Modules linked in:
---[ end trace 15bdec020000363f ]---
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:ffffc90019c5fc28 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000000 RCX: ffff88801b910000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000060
RBP: 0000000000000008 R08: ffffffff83fac4ec R09: fffffbfff167c6b1
R10: fffffbfff167c6b1 R11: 0000000000000000 R12: ffff8882185c3d08
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff110430b87a1
FS:  00000000017a5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000118c000 CR3: 0000000218a8e000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400