print_req_error: I/O error, dev nbd0, sector 0
F2FS-fs (nbd0): Unable to read 1th superblock
block nbd0: Attempted send on invalid socket
print_req_error: I/O error, dev nbd0, sector 8
F2FS-fs (nbd0): Unable to read 2th superblock
BUG: unable to handle kernel paging request at fffffffffffffff4
PGD 926d067 P4D 926d067 PUD 926f067 PMD 0 
kobject: 'loop2' (00000000e5a86811): kobject_uevent_env
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 9609 Comm: syz-executor3 Not tainted 4.19.0-rc8-next-20181019+ #98
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:parse_monolithic_mount_data fs/namespace.c:2369 [inline]
RIP: 0010:do_remount fs/namespace.c:2402 [inline]
RIP: 0010:do_mount+0xb98/0x1d90 fs/namespace.c:2965
Code: 06 00 48 89 c2 48 89 c3 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 8a 11 00 00 48 b8 00 00 00 00 00 fc ff df <4c> 8b 33 49 8d 7e 18 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 5e 11
block nbd0: Attempted send on invalid socket
RSP: 0018:ffff880186327c28 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: ffffc90007eae000
RDX: 1ffffffffffffffe RSI: ffffffff81e011ec RDI: 0000000000000282
RBP: ffff880186327db0 R08: ffff8801c2482440 R09: ffffed003b5e5b4f
R10: ffffed003b5e5b4f R11: ffff8801daf2da7b R12: ffff8801ba9b5030
R13: ffff8801c9fe8b00 R14: ffff8801c9fe8b00 R15: ffff880184cc8880
print_req_error: I/O error, dev nbd0, sector 0
FS:  00007f93afa65700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff4 CR3: 00000001b9979000 CR4: 00000000001426e0
F2FS-fs (nbd0): Unable to read 1th superblock
DR0: 000000000000b8c4 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
kobject: 'loop2' (00000000e5a86811): fill_kobj_path: path = '/devices/virtual/block/loop2'
kobject: 'loop1' (00000000f2c09f9a): kobject_uevent_env
block nbd0: Attempted send on invalid socket
 ksys_mount+0x12d/0x140 fs/namespace.c:3190
 __do_sys_mount fs/namespace.c:3204 [inline]
 __se_sys_mount fs/namespace.c:3201 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3201
print_req_error: I/O error, dev nbd0, sector 8
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
F2FS-fs (nbd0): Unable to read 2th superblock
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459fda
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 7d 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 5a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f93afa64a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f93afa64b30 RCX: 0000000000459fda
RDX: 00007f93afa64ad0 RSI: 0000000020000080 RDI: 00007f93afa64af0
RBP: 0000000020000080 R08: 00007f93afa64b30 R09: 00007f93afa64ad0
R10: 0000000000100020 R11: 0000000000000206 R12: 0000000000000004
R13: 0000000000100020 R14: 00000000004d7d88 R15: 0000000000000003
Modules linked in:
CR2: fffffffffffffff4
---[ end trace b85e9ce3831fea28 ]---
RIP: 0010:parse_monolithic_mount_data fs/namespace.c:2369 [inline]
RIP: 0010:do_remount fs/namespace.c:2402 [inline]
RIP: 0010:do_mount+0xb98/0x1d90 fs/namespace.c:2965
Code: 06 00 48 89 c2 48 89 c3 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 8a 11 00 00 48 b8 00 00 00 00 00 fc ff df <4c> 8b 33 49 8d 7e 18 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 5e 11
RSP: 0018:ffff880186327c28 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: ffffc90007eae000
RDX: 1ffffffffffffffe RSI: ffffffff81e011ec RDI: 0000000000000282
RBP: ffff880186327db0 R08: ffff8801c2482440 R09: ffffed003b5e5b4f
R10: ffffed003b5e5b4f R11: ffff8801daf2da7b R12: ffff8801ba9b5030
R13: ffff8801c9fe8b00 R14: ffff8801c9fe8b00 R15: ffff880184cc8880
FS:  00007f93afa65700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff4 CR3: 00000001b9979000 CR4: 00000000001426e0
DR0: 000000000000b8c4 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400