Unknown ioctl 8822
BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0
PGD 800000013f4c7067 P4D 800000013f4c7067 PUD 13f4cb067 PMD 0 
Oops: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 25602 Comm: syz-executor6 Not tainted 4.17.0+ #22
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:slab_equal_or_root mm/slab.h:228 [inline]
RIP: 0010:cache_from_obj mm/slab.h:374 [inline]
RIP: 0010:kmem_cache_free+0x31d/0x2bc0 mm/slub.c:3022
RSP: 0018:ffff880054fef608 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000000d0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffea0006000030
RBP: ffff880054fef758 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: 000000018020001d R12: 0000000000000000
R13: ffff8801d4a68780 R14: 0000000000000000 R15: ffffea0000000000
FS:  00007efdfac2c700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000d0 CR3: 000000013f4e8000 CR4: 00000000001406f0
DR0: 0000000020000040 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 free_uts_ns+0x20a/0x230 kernel/utsname.c:118
 kref_put include/linux/kref.h:70 [inline]
 put_uts_ns include/linux/utsname.h:45 [inline]
 free_nsproxy+0x183/0x4c0 kernel/nsproxy.c:178
 switch_task_namespaces kernel/nsproxy.c:229 [inline]
 exit_task_namespaces+0x174/0x200 kernel/nsproxy.c:234
 do_exit+0x1109/0x3930 kernel/exit.c:866
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 get_signal+0x1405/0x1ec0 kernel/signal.c:2482
 do_signal+0xb8/0x1d20 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:162 [inline]
 prepare_exit_to_usermode+0x271/0x3a0 arch/x86/entry/common.c:196
 syscall_return_slowpath+0xe9/0x710 arch/x86/entry/common.c:265
 do_syscall_64+0x1ad/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x455ba9
RSP: 002b:00007efdfac2bce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 000000000072bec0 RCX: 0000000000455ba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072bec0
RBP: 000000000072bec0 R08: 0000000000000000 R09: 000000000072bea0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000a3e81f R14: 00007efdfac2c9c0 R15: 0000000000000000
Code: 31 e9 48 f7 d0 48 21 c8 0f 84 67 01 00 00 4d 39 ec 0f 84 7b 01 00 00 89 55 a0 49 8d 9c 24 d0 00 00 00 4d 85 f6 0f 85 6f 11 00 00 <4c> 8b 2b 48 89 df e8 18 77 03 00 48 8b 00 48 0b 45 b8 74 16 4c 
RIP: slab_equal_or_root mm/slab.h:228 [inline] RSP: ffff880054fef608
RIP: cache_from_obj mm/slab.h:374 [inline] RSP: ffff880054fef608
RIP: kmem_cache_free+0x31d/0x2bc0 mm/slub.c:3022 RSP: ffff880054fef608
CR2: 00000000000000d0
---[ end trace 03861204a11eec6a ]---