BUG: corrupted list in p9_fd_cancelled (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    36146921 Merge tag 'hyperv-fixes-signed' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169f691e600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6919752cc1b760b4
dashboard link: https://syzkaller.appspot.com/bug?extid=1d26c4ed77bc6c5ed5e6
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d03ba6600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1d26c4ed77bc6c5ed5e6@xxxxxxxxxxxxxxxxxxxxxxxxx

list_del corruption, ffff88808ecdbfb0->next is LIST_POISON1  
(dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:45!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 20174 Comm: syz-executor.1 Not tainted 5.3.0-rc5+ #125
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:__list_del_entry_valid.cold+0x23/0x4f lib/list_debug.c:45
Code: e8 d5 06 1e fe 0f 0b 4c 89 f6 48 c7 c7 e0 26 c6 87 e8 c4 06 1e fe 0f  
0b 4c 89 ea 4c 89 f6 48 c7 c7 20 26 c6 87 e8 b0 06 1e fe <0f> 0b 4c 89 e2  
4c 89 f6 48 c7 c7 80 26 c6 87 e8 9c 06 1e fe 0f 0b
RSP: 0018:ffff8880994076d8 EFLAGS: 00010286
RAX: 000000000000004e RBX: 1ffff11013280ee9 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815c2526 RDI: ffffed1013280ecd
RBP: ffff8880994076f0 R08: 000000000000004e R09: ffffed1015d060d1
R10: ffffed1015d060d0 R11: ffff8880ae830687 R12: dead000000000122
R13: dead000000000100 R14: ffff88808ecdbfb0 R15: ffff88808ecdbfb8
FS:  00007fb2aca54700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffee6574f58 CR3: 00000000a8e6d000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __list_del_entry include/linux/list.h:131 [inline]
 list_del include/linux/list.h:139 [inline]
 p9_fd_cancelled+0x3c/0x1c0 net/9p/trans_fd.c:710
 p9_client_flush+0x1b7/0x1f0 net/9p/client.c:674
 p9_client_rpc+0x112f/0x12a0 net/9p/client.c:781
 p9_client_version net/9p/client.c:952 [inline]
 p9_client_create+0xb7f/0x1430 net/9p/client.c:1052
 v9fs_session_init+0x1e7/0x18c0 fs/9p/v9fs.c:406
 v9fs_mount+0x7d/0x920 fs/9p/vfs_super.c:120
 legacy_get_tree+0x108/0x220 fs/fs_context.c:661
 vfs_get_tree+0x8e/0x390 fs/super.c:1413
 do_new_mount fs/namespace.c:2791 [inline]
 do_mount+0x13b3/0x1c30 fs/namespace.c:3111
 ksys_mount+0xdb/0x150 fs/namespace.c:3320
 __do_sys_mount fs/namespace.c:3334 [inline]
 __se_sys_mount fs/namespace.c:3331 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3331
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459879
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb2aca53c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459879
RDX: 00000000200002c0 RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000075bfc8 R08: 0000000020000400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb2aca546d4
R13: 00000000004c5e2f R14: 00000000004da930 R15: 00000000ffffffff
Modules linked in:
---[ end trace c76f5f29f0af3347 ]---
RIP: 0010:__list_del_entry_valid.cold+0x23/0x4f lib/list_debug.c:45
Code: e8 d5 06 1e fe 0f 0b 4c 89 f6 48 c7 c7 e0 26 c6 87 e8 c4 06 1e fe 0f  
0b 4c 89 ea 4c 89 f6 48 c7 c7 20 26 c6 87 e8 b0 06 1e fe <0f> 0b 4c 89 e2  
4c 89 f6 48 c7 c7 80 26 c6 87 e8 9c 06 1e fe 0f 0b
RSP: 0018:ffff8880994076d8 EFLAGS: 00010286
RAX: 000000000000004e RBX: 1ffff11013280ee9 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815c2526 RDI: ffffed1013280ecd
RBP: ffff8880994076f0 R08: 000000000000004e R09: ffffed1015d060d1
R10: ffffed1015d060d0 R11: ffff8880ae830687 R12: dead000000000122
R13: dead000000000100 R14: ffff88808ecdbfb0 R15: ffff88808ecdbfb8
FS:  00007fb2aca54700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffee6574f58 CR3: 00000000a8e6d000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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