WARNING in __list_del_entry

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 54068d61 Merge 4.9.122 into android-4.9
git tree: android-4.9
console output: https://syzkaller.appspot.com/x/log.txt?x=1078479a400000
kernel config: https://syzkaller.appspot.com/x/.config?x=c7451be69185755b
dashboard link: https://syzkaller.appspot.com/bug?extid=9b4351edc23889e10d7f
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17a0e79a400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1411bc82400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9b4351...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 23247 at lib/list_debug.c:53
__list_del_entry+0x111/0x1c0 lib/list_debug.c:51
list_del corruption, ffff8801aa140028->next is LIST_POISON1
(dead000000000100)
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 23247 Comm: syz-executor983 Not tainted 4.9.122-g54068d6 #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
ffff8801a08b7450 ffffffff81eb8829 ffffffff83c48ac0 00000000ffffffff
0000000000000000 0000000000000000 0000000000000035 ffff8801a08b7510
ffffffff81423f35 0000000041b58ab3 ffffffff843bb838 ffffffff81423d76
Call Trace:
[<ffffffff81eb8829>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81eb8829>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
[<ffffffff81423f35>] panic+0x1bf/0x3bc kernel/panic.c:179
[<ffffffff81424221>] __warn.cold.9+0xc1/0x17f kernel/panic.c:542
[<ffffffff81138212>] warn_slowpath_fmt+0xc2/0x100 kernel/panic.c:565
[<ffffffff81f206f1>] __list_del_entry+0x111/0x1c0 lib/list_debug.c:51
[<ffffffff81f207ad>] list_del+0xd/0x70 lib/list_debug.c:77
[<ffffffff839c9459>] p9_fd_cancel+0x69/0xb0 net/9p/trans_fd.c:700
[<ffffffff839b9141>] p9_client_rpc+0x9e1/0x1140 net/9p/client.c:776
[<ffffffff839bb451>] p9_client_version net/9p/client.c:950 [inline]
[<ffffffff839bb451>] p9_client_create+0x951/0x10a0 net/9p/client.c:1043
[<ffffffff8195f5e3>] v9fs_session_init+0x333/0x13a0 fs/9p/v9fs.c:343
[<ffffffff81950edd>] v9fs_mount+0x7d/0x810 fs/9p/vfs_super.c:130
[<ffffffff81581d9c>] mount_fs+0x28c/0x370 fs/super.c:1206
[<ffffffff815e1681>] vfs_kern_mount.part.29+0xd1/0x3d0 fs/namespace.c:1000
[<ffffffff815e8ea9>] vfs_kern_mount fs/namespace.c:982 [inline]
[<ffffffff815e8ea9>] do_new_mount fs/namespace.c:2537 [inline]
[<ffffffff815e8ea9>] do_mount+0x3c9/0x2740 fs/namespace.c:2859
[<ffffffff815ebbfe>] SYSC_mount fs/namespace.c:3075 [inline]
[<ffffffff815ebbfe>] SyS_mount+0xfe/0x110 fs/namespace.c:3052
[<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
[<ffffffff83a00cd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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