RBP: 00007ff23e2b31d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007fff376c974f R14: 00007ff23e2b3300 R15: 0000000000022000
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 15927 Comm: syz-executor.4 Not tainted 4.14.262-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888054edc0c0 task.stack: ffff8880a1538000
RIP: 0010:sysfs_do_create_link_sd+0x56/0x120 fs/sysfs/symlink.c:35
RSP: 0018:ffff8880a153f4e0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000010 RCX: 0000000000002d78
RDX: 0000000000000008 RSI: 0000000000000001 RDI: 0000000000000040
RBP: ffffffff87cbb660 R08: ffffffff8b9b4680 R09: 00000000000400c7
R10: ffff888054edc9c0 R11: ffff888054edc0c0 R12: ffff8880ae9e6620
R13: ffffffff87cbb660 R14: 0000000000000001 R15: ffff88808c7f645c
FS:  00007ff23e2b3700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6d36e9e718 CR3: 000000009484b000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x5f/0xc0 fs/sysfs/symlink.c:92
 device_add_disk+0x9f8/0xdc0 block/genhd.c:691
 add_disk include/linux/genhd.h:396 [inline]
 nbd_dev_add+0x60e/0x800 drivers/block/nbd.c:1675
 nbd_genl_connect+0x3a4/0x1400 drivers/block/nbd.c:1756
 genl_family_rcv_msg+0x572/0xb20 net/netlink/genetlink.c:600
 genl_rcv_msg+0xaf/0x140 net/netlink/genetlink.c:625
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2446
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1294 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1320
 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7ff23f93dfe9
RSP: 002b:00007ff23e2b3168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff23fa50f60 RCX: 00007ff23f93dfe9
RDX: 0000000000000000 RSI: 0000000020000380 RDI: 0000000000000005
RBP: 00007ff23e2b31d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007fff376c974f R14: 00007ff23e2b3300 R15: 0000000000022000
Code: 84 a1 00 00 00 e8 7b 6c b1 ff 48 c7 c7 80 c8 04 89 e8 9f 2a 80 05 48 8d 7b 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 a7 00 00 00 4c 8b 6b 30 4d 85 ed 74 4f e8 42 
RIP: sysfs_do_create_link_sd+0x56/0x120 fs/sysfs/symlink.c:35 RSP: ffff8880a153f4e0
---[ end trace eaf045c57dd4af90 ]---
----------------
Code disassembly (best guess):
   0:	84 a1 00 00 00 e8    	test   %ah,-0x18000000(%rcx)
   6:	7b 6c                	jnp    0x74
   8:	b1 ff                	mov    $0xff,%cl
   a:	48 c7 c7 80 c8 04 89 	mov    $0xffffffff8904c880,%rdi
  11:	e8 9f 2a 80 05       	callq  0x5802ab5
  16:	48 8d 7b 30          	lea    0x30(%rbx),%rdi
  1a:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  21:	fc ff df
  24:	48 89 fa             	mov    %rdi,%rdx
  27:	48 c1 ea 03          	shr    $0x3,%rdx
* 2b:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2f:	0f 85 a7 00 00 00    	jne    0xdc
  35:	4c 8b 6b 30          	mov    0x30(%rbx),%r13
  39:	4d 85 ed             	test   %r13,%r13
  3c:	74 4f                	je     0x8d
  3e:	e8                   	.byte 0xe8
  3f:	42                   	rex.X