list_del corruption. prev->next should be ffff8801a3ee09a8, but was ffff8801cd58f3b0
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:53!
invalid opcode: 0000 [#1] SMP KASAN
CPU: 1 PID: 7466 Comm: syz-executor804 Not tainted 4.18.0-rc4-next-20180710+ #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__list_del_entry_valid.cold.1+0x48/0x58 lib/list_debug.c:51
Code: 86 1a 88 e8 e6 1e ff fd 0f 0b 48 89 de 48 c7 c7 60 87 1a 88 e8 d5 1e ff fd 0f 0b 48 89 de 48 c7 c7 00 87 1a 88 e8 c4 1e ff fd <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 
RSP: 0018:ffff8801cb22f270 EFLAGS: 00010286
RAX: 0000000000000054 RBX: ffff8801a3ee09a8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81634451 RDI: 0000000000000001
RBP: ffff8801cb22f288 R08: ffff8801cad042c0 R09: ffffed003b5e4fc0
R10: ffffed003b5e4fc0 R11: ffff8801daf27e07 R12: ffff8801cd58f3b0
R13: ffff8801cd58f3b0 R14: ffff8801a3ee09a8 R15: ffff8801a3ee09b0
FS:  00007fda4520e700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000046a450 CR3: 00000001cb36e000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __list_del_entry include/linux/list.h:117 [inline]
 list_del include/linux/list.h:125 [inline]
 p9_fd_cancel+0x104/0x360 net/9p/trans_fd.c:690
 p9_client_rpc+0xf1f/0x1400 net/9p/client.c:800
 p9_client_version net/9p/client.c:976 [inline]
 p9_client_create+0xd09/0x16c9 net/9p/client.c:1069
 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400
 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135
 legacy_get_tree+0x118/0x440 fs/fs_context.c:659
 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743
 do_new_mount fs/namespace.c:2567 [inline]
 do_mount+0x6c1/0x1fb0 fs/namespace.c:2889
 ksys_mount+0x12d/0x140 fs/namespace.c:3105
 __do_sys_mount fs/namespace.c:3119 [inline]
 __se_sys_mount fs/namespace.c:3116 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3116
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x445e69
Code: e8 ec ba 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 ab 0e fc ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007fda4520dda8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dbc24 RCX: 0000000000445e69
RDX: 0000000020002d40 RSI: 0000000020002d00 RDI: 0000000000000000
RBP: 00000000006dbc20 R08: 0000000020002d80 R09: 0000000000000000
R10: 0000000000200000 R11: 0000000000000202 R12: 0030656c69662f2e
R13: 633d737365636361 R14: 64663d736e617274 R15: 0000000000000001
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
---[ end trace e1149ac3cf24e085 ]---
RIP: 0010:__list_del_entry_valid.cold.1+0x48/0x58 lib/list_debug.c:51
Code: 86 1a 88 e8 e6 1e ff fd 0f 0b 48 89 de 48 c7 c7 60 87 1a 88 e8 d5 1e ff fd 0f 0b 48 89 de 48 c7 c7 00 87 1a 88 e8 c4 1e ff fd <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 
RSP: 0018:ffff8801cb22f270 EFLAGS: 00010286
RAX: 0000000000000054 RBX: ffff8801a3ee09a8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81634451 RDI: 0000000000000001
RBP: ffff8801cb22f288 R08: ffff8801cad042c0 R09: ffffed003b5e4fc0
R10: ffffed003b5e4fc0 R11: ffff8801daf27e07 R12: ffff8801cd58f3b0
R13: ffff8801cd58f3b0 R14: ffff8801a3ee09a8 R15: ffff8801a3ee09b0
FS:  00007fda4520e700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000046a450 CR3: 00000001cb36e000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400