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: 8259 Comm: syz-executor.5 Not tainted 5.12.0-rc6-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: 84 00 00 00 00 00 0f 1f 00 55 41 56 53 48 89 fb 49 be 00 00 00 00 00 fc ff df e8 aa 17 b1 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:ffffc9001a22fc20 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000000 RCX: ffff88801b848000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000060
RBP: 0000000000000008 R08: ffffffff8434a65c R09: fffffbfff1f272c3
R10: fffffbfff1f272c3 R11: 0000000000000000 R12: ffff888018875e08
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff1100310ebc1
FS:  00000000017fa400(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000543038 CR3: 000000006fe77000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 tty_unregister_device+0xed/0x170 drivers/tty/tty_io.c:3343
 gsmld_detach_gsm drivers/tty/n_gsm.c:2409 [inline]
 gsmld_close+0xa0/0x1e0 drivers/tty/n_gsm.c:2478
 tty_ldisc_kill drivers/tty/tty_ldisc.c:636 [inline]
 tty_ldisc_hangup+0x432/0x650 drivers/tty/tty_ldisc.c:756
 __tty_hangup+0x4d4/0x750 drivers/tty/tty_io.c:639
 tty_release+0x30c/0xef0 drivers/tty/tty_io.c:1779
 __fput+0x352/0x7b0 fs/file_table.c:280
 task_work_run+0x146/0x1c0 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x10b/0x1e0 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x26/0x70 kernel/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x41926b
Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffe79b3ce10 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 000000000041926b
RDX: 0000000000000000 RSI: 000000000a63e4ef RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000001b304213e8
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000056c9e0
R13: 000000000056c9e0 R14: 000000000056bf60 R15: 0000000000078265
Modules linked in:
---[ end trace e79097a41d21ad31 ]---
RIP: 0010:cdev_del+0x21/0x90 fs/char_dev.c:596
Code: 84 00 00 00 00 00 0f 1f 00 55 41 56 53 48 89 fb 49 be 00 00 00 00 00 fc ff df e8 aa 17 b1 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:ffffc9001a22fc20 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000000 RCX: ffff88801b848000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000060
RBP: 0000000000000008 R08: ffffffff8434a65c R09: fffffbfff1f272c3
R10: fffffbfff1f272c3 R11: 0000000000000000 R12: ffff888018875e08
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff1100310ebc1
FS:  00000000017fa400(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f89fc3e9000 CR3: 000000006fe77000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600