BUG: corrupted list in do_mount

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 050272a0 Linux 4.14.177
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10948f80100000
kernel config: https://syzkaller.appspot.com/x/.config?x=b24dc669afb42f8b
dashboard link: https://syzkaller.appspot.com/bug?extid=87940e7e8e095c0e06eb
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+87940e...@syzkaller.appspotmail.com

should_failslab+0xd6/0x130 mm/failslab.c:32
list_add double add: new=ffff88805e0bc120, prev=ffffffff886d9c00, next=ffff88805e0bc120.
slab_pre_alloc_hook mm/slab.h:421 [inline]
slab_alloc mm/slab.c:3376 [inline]
kmem_cache_alloc_trace+0x2db/0x7b0 mm/slab.c:3616
------------[ cut here ]------------
kmalloc include/linux/slab.h:488 [inline]
kzalloc include/linux/slab.h:661 [inline]
nfs_alloc_server+0x41/0x4a0 fs/nfs/client.c:882
kernel BUG at lib/list_debug.c:29!
nfs_create_server+0x2c/0x570 fs/nfs/client.c:948
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
nfs_try_mount+0x11d/0x760 fs/nfs/super.c:1879
Modules linked in:
CPU: 1 PID: 6354 Comm: syz-executor.3 Not tainted 4.14.177-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88805ed6e0c0 task.stack: ffff88805ed70000
RIP: 0010:__list_add_valid.cold+0x26/0x3c lib/list_debug.c:29
RSP: 0018:ffff88805ed77c70 EFLAGS: 00010086
RAX: 0000000000000058 RBX: ffff88805e0bc0c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff86ac0860 RDI: ffffed100bdaef84
nfs_fs_mount+0x983/0x2b30 fs/nfs/super.c:2692
RBP: ffff88805e0bc120 R08: 0000000000000058 R09: 0000000000000002
R10: ffff88805ed77870 R11: ffff88805ed6e0c0 R12: ffff88805e0bc120
R13: ffff88805e0bc120 R14: ffff888057d5cb08 R15: ffffffff8b042c20
FS: 00000000029b6940(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000073b138 CR3: 000000005ed7a000 CR4: 00000000001406e0
mount_fs+0x92/0x2a0 fs/super.c:1237
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vfs_kern_mount fs/namespace.c:1036 [inline]
do_new_mount fs/namespace.c:2549 [inline]
do_mount+0x3c9/0x24f0 fs/namespace.c:2879
__list_add include/linux/list.h:60 [inline]
list_add include/linux/list.h:79 [inline]
__put_net+0x3a/0x100 net/core/net_namespace.c:530
put_net include/net/net_namespace.h:219 [inline]
__sk_destruct+0x508/0x640 net/core/sock.c:1580
sk_destruct+0x97/0xc0 net/core/sock.c:1596
__sk_free+0x4c/0x220 net/core/sock.c:1604
sk_free+0x2b/0x40 net/core/sock.c:1615
sock_put include/net/sock.h:1658 [inline]
tcp_close+0x9d5/0xf30 net/ipv4/tcp.c:2304
inet_release+0xdf/0x1b0 net/ipv4/af_inet.c:425
__sock_release+0xcd/0x2b0 net/socket.c:602
sock_close+0x15/0x20 net/socket.c:1139
__fput+0x25f/0x790 fs/file_table.c:210
task_work_run+0x113/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164
SYSC_mount fs/namespace.c:3095 [inline]
SyS_mount+0xa8/0x120 fs/namespace.c:3072
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x42/0xb7
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
RIP: 0033:0x416400
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RSP: 002b:00007fff88ffb5f8 EFLAGS: 00000246
RIP: 0033:0x45c829
ORIG_RAX: 0000000000000003
RSP: 002b:00007f9263cabc78 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000416400
ORIG_RAX: 00000000000000a5
RDX: 00000000000000e0 RSI: 00007fff88ffb6c0 RDI: 0000000000000003
RAX: ffffffffffffffda RBX: 00000000004f5d80 RCX: 000000000045c829
RBP: 00007fff88ffb610 R08: 00007fff88ffb60c R09: 000000000000000a
RDX: 0000000020fb5ffc RSI: 0000000020343ff8 RDI: 0000000000000000
R10: 00007fff88ffb610 R11: 0000000000000246 R12: 0000000000000003
RBP: 000000000078bf00 R08: 000000002000a000 R09: 0000000000000000
R13: 000000000073c4c0 R14: 000000000073bdc8 R15: 0000000000001380
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
Code:
R13: 000000000000074b R14: 00000000004ca135 R15: 00007f9263cac6d4
e9
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
57 ff ff ff 4c 89 e1 48 c7 c7 40 57 e4 86 e8 cd b2 4a fe 0f 0b 48 89 f2 4c 89 e1 48 89 ee 48 c7 c7 80 58 e4 86 e8 b6 b2 4a fe <0f> 0b 48 89 f1 48 c7 c7 00 58 e4 86 4c 89 e6 e8 a2 b2 4a fe 0f
RIP: __list_add_valid.cold+0x26/0x3c lib/list_debug.c:29 RSP: ffff88805ed77c70
---[ end trace 0e84ac85ff79796b ]---


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.