Oops: general protection fault, probably for non-canonical address 0xdffffc00000000b2: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000590-0x0000000000000597]
CPU: 0 UID: 0 PID: 23249 Comm: syz.2.4994 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:vc_deallocate+0x303/0x3e0
Code: e8 22 23 d7 fc 49 c7 07 00 00 00 00 eb 0e e8 84 23 73 fc eb 05 e8 7d 23 73 fc 31 db 4c 8d b3 90 05 00 00 4d 89 f4 49 c1 ec 03 <43> 80 3c 2c 00 74 08 4c 89 f7 e8 fe 21 d7 fc 4d 8b 3e 4d 85 ff 74
RSP: 0018:ffffc900049379e0 EFLAGS: 00010206
RAX: ffffffff854c8703 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc90008921000 RSI: 000000000000039f RDI: 00000000000003a0
RBP: ffffc90004937a90 R08: ffffffff8fc3c6cf R09: 1ffffffff1f878d9
R10: dffffc0000000000 R11: fffffbfff1f878da R12: 00000000000000b2
R13: dffffc0000000000 R14: 0000000000000590 R15: ffffffff9a034a30
FS:  00007f593f96c6c0(0000) GS:ffff8880b83f1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001f80 CR3: 00000000309cc000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 vt_disallocate_all+0x60/0xe0
 vt_ioctl+0x1adc/0x1f20
 tty_ioctl+0x929/0xde0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f593eb8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f593f96c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f593edc5fa0 RCX: 00007f593eb8ebe9
RDX: 0000000000000000 RSI: 0000000000005608 RDI: 0000000000000003
RBP: 00007f593ec11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f593edc6038 R14: 00007f593edc5fa0 R15: 00007fff7dae9408
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:vc_deallocate+0x303/0x3e0
Code: e8 22 23 d7 fc 49 c7 07 00 00 00 00 eb 0e e8 84 23 73 fc eb 05 e8 7d 23 73 fc 31 db 4c 8d b3 90 05 00 00 4d 89 f4 49 c1 ec 03 <43> 80 3c 2c 00 74 08 4c 89 f7 e8 fe 21 d7 fc 4d 8b 3e 4d 85 ff 74
RSP: 0018:ffffc900049379e0 EFLAGS: 00010206
RAX: ffffffff854c8703 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc90008921000 RSI: 000000000000039f RDI: 00000000000003a0
RBP: ffffc90004937a90 R08: ffffffff8fc3c6cf R09: 1ffffffff1f878d9
R10: dffffc0000000000 R11: fffffbfff1f878da R12: 00000000000000b2
R13: dffffc0000000000 R14: 0000000000000590 R15: ffffffff9a034a30
FS:  00007f593f96c6c0(0000) GS:ffff8880b83f1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001f80 CR3: 00000000309cc000 CR4: 00000000000006f0
