kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 19924 Comm: syz-executor2 Not tainted 4.13.0-rc4-next-20170811 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88003a7b01c0 task.stack: ffff880039e20000
RIP: 0010:__list_del_entry_valid+0x7e/0x150 lib/list_debug.c:51
RSP: 0018:ffff880039e27b30 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88003aa62918 RDI: ffff88003aa62920
RBP: ffff880039e27b48 R08: ffffffff818c11c1 R09: 0000000000000000
R10: ffff880039e27998 R11: ffffffff85b972c0 R12: 0000000000000000
sg_write: data in/out 236912604/4 bytes for SCSI command 0x27-- guessing data in;
   program syz-executor6 not setting count and/or reply_len properly
R13: dffffc0000000000 R14: 1ffff100073c4f8a R15: ffff88003aa62918
FS:  00007fdec33a3700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdec3360db8 CR3: 000000003ad64000 CR4: 00000000000006f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 000000001714bf90
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 __list_del_entry include/linux/list.h:116 [inline]
 list_del include/linux/list.h:124 [inline]
 unregister_shrinker+0x79/0x300 mm/vmscan.c:300
 deactivate_locked_super+0x64/0xd0 fs/super.c:307
 deactivate_super+0x141/0x1b0 fs/super.c:339
 cleanup_mnt+0xb2/0x150 fs/namespace.c:1113
 __cleanup_mnt+0x16/0x20 fs/namespace.c:1120
 task_work_run+0x199/0x270 kernel/task_work.c:112
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x2a6/0x300 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath+0x42f/0x500 arch/x86/entry/common.c:266
 entry_SYSCALL_64_fastpath+0xbc/0xbe
RIP: 0033:0x446739
RSP: 002b:00007fdec33a2c08 EFLAGS: 00000292 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffec RBX: 0000000020018000 RCX: 0000000000446739
RDX: 0000000020018ffa RSI: 0000000020fa1000 RDI: 0000000020018000
RBP: 00000000007080a8 R08: 0000000020fa1fff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000016
R13: 0000000000003820 R14: 00000000006e58e0 R15: 0000000020fa1000
cgroup: cgroup2: unknown option ""
Code: 00 00 00 00 ad de 49 39 c4 74 66 48 b8 00 02 00 00 00 00 ad de 48 89 da 48 39 c3 74 65 48 c1 ea 03 48 b8 00 00 00 00 00 fc ff df <80> 3c 02 00 75 7b 48 8b 13 48 39 f2 75 57 49 8d 7c 24 08 48 b8 
RIP: __list_del_entry_valid+0x7e/0x150 lib/list_debug.c:51 RSP: ffff880039e27b30
---[ end trace 378f1f5622f49a4b ]---