general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
CPU: 1 PID: 16839 Comm: syz-executor.5 Not tainted 5.10.0-rc2-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 2a 60 b3 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:ffffc9001956fc68 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000000 RCX: ffff888025f64ec0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000060
RBP: 0000000000000008 R08: ffffffff841e793c R09: fffffbfff1d92c83
R10: fffffbfff1d92c83 R11: 0000000000000000 R12: ffff888013347708
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff11002668ee1
FS:  0000000001e2a940(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e222000 CR3: 00000000127e2000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tty_unregister_device+0xed/0x170 drivers/tty/tty_io.c:3191
 gsmld_detach_gsm drivers/tty/n_gsm.c:2407 [inline]
 gsmld_close+0xa0/0x1e0 drivers/tty/n_gsm.c:2476
 tty_ldisc_kill drivers/tty/tty_ldisc.c:636 [inline]
 tty_ldisc_release+0x220/0x580 drivers/tty/tty_ldisc.c:808
 tty_release_struct+0x27/0xd0 drivers/tty/tty_io.c:1614
 tty_release+0xc63/0xef0 drivers/tty/tty_io.c:1785
 __fput+0x34f/0x7b0 fs/file_table.c:281
 task_work_run+0x137/0x1c0 kernel/task_work.c:151
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
 exit_to_user_mode_prepare+0xe4/0x170 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x4a/0x170 kernel/entry/common.c:266
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x417811
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 a4 1a 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:00007ffddb2064d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000417811
RDX: 0000000000000000 RSI: 0000000000000979 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000087244979 R09: 000000008724497d
R10: 00007ffddb2065b0 R11: 0000000000000293 R12: 000000000118c9a0
R13: 000000000118c9a0 R14: 00000000000003e8 R15: 000000000118c07c
Modules linked in:
---[ end trace 3ce776b8fb459067 ]---
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 2a 60 b3 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:ffffc9001956fc68 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000000 RCX: ffff888025f64ec0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000060
RBP: 0000000000000008 R08: ffffffff841e793c R09: fffffbfff1d92c83
R10: fffffbfff1d92c83 R11: 0000000000000000 R12: ffff888013347708
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff11002668ee1
FS:  0000000001e2a940(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005569758db0c8 CR3: 00000000127e2000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400