BUG: corrupted list in p9_read_work (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: edeca3a769ad Merge tag 'sound-4.20-rc4' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13dee26d400000
kernel config: https://syzkaller.appspot.com/x/.config?x=73e2bc0cb6463446
dashboard link: https://syzkaller.appspot.com/bug?extid=77a25acfa0382e06ab23
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1459062b400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+77a25a...@syzkaller.appspotmail.com

8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
list_del corruption, ffff8881d12ddfb0->next is LIST_POISON1
(dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:47!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 2915 Comm: kworker/0:2 Not tainted 4.20.0-rc3+ #124
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events p9_read_work
RIP: 0010:__list_del_entry_valid.cold.1+0x26/0x4a lib/list_debug.c:45
Code: d2 fd 0f 0b 4c 89 e2 48 89 de 48 c7 c7 00 d1 60 88 e8 c6 37 d2 fd 0f
0b 4c 89 ea 48 89 de 48 c7 c7 60 d0 60 88 e8 b2 37 d2 fd <0f> 0b 48 89 de
48 c7 c7 c0 d1 60 88 e8 a1 37 d2 fd 0f 0b 48 89 de
RSP: 0018:ffff8881cb9075c0 EFLAGS: 00010286
RAX: 000000000000004e RBX: ffff8881d12ddfb0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8165eaf5 RDI: 0000000000000005
RBP: ffff8881cb9075d8 R08: ffff8881cbb30400 R09: ffffed103b5c5020
R10: ffffed103b5c5020 R11: ffff8881dae28107 R12: dead000000000200
R13: dead000000000100 R14: ffff8881d8fd6a90 R15: ffff8881d8fd6a50
FS: 0000000000000000(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001b3f06000 CR4: 00000000001406f0
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_read_work+0xa95/0x1140 net/9p/trans_fd.c:378
process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
kthread+0x35a/0x440 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace e66a284578a06221 ]---
RIP: 0010:__list_del_entry_valid.cold.1+0x26/0x4a lib/list_debug.c:45
Code: d2 fd 0f 0b 4c 89 e2 48 89 de 48 c7 c7 00 d1 60 88 e8 c6 37 d2 fd 0f
0b 4c 89 ea 48 89 de 48 c7 c7 60 d0 60 88 e8 b2 37 d2 fd <0f> 0b 48 89 de
48 c7 c7 c0 d1 60 88 e8 a1 37 d2 fd 0f 0b 48 89 de
RSP: 0018:ffff8881cb9075c0 EFLAGS: 00010286
RAX: 000000000000004e RBX: ffff8881d12ddfb0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8165eaf5 RDI: 0000000000000005
RBP: ffff8881cb9075d8 R08: ffff8881cbb30400 R09: ffffed103b5c5020
R10: ffffed103b5c5020 R11: ffff8881dae28107 R12: dead000000000200
R13: dead000000000100 R14: ffff8881d8fd6a90 R15: ffff8881d8fd6a50
FS: 0000000000000000(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001b3f06000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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