[syzbot] [v9fs?] WARNING in v9fs_init_request

[syzbot <syzbot+0354394655e838206fba@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    8d025e2092e2 Merge tag 'erofs-for-6.9-rc2-fixes' of git://..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17cb6d7e180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a2fbd4c518bbb6b3
dashboard link: https://syzkaller.appspot.com/bug?extid=0354394655e838206fba
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-8d025e20.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8028eb34add3/vmlinux-8d025e20.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1edea22db964/bzImage-8d025e20.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0354394655e838206fba@syzkaller.appspotmail.com

------------[ cut here ]------------
folio expected an open fid inode->i_ino=2
WARNING: CPU: 2 PID: 1121 at fs/9p/vfs_addr.c:115 v9fs_init_request+0x346/0x380 fs/9p/vfs_addr.c:115
Modules linked in:
CPU: 2 PID: 1121 Comm: kworker/u32:9 Not tainted 6.9.0-rc1-syzkaller-00061-g8d025e2092e2 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: writeback wb_workfn (flush-9p-36)
RIP: 0010:v9fs_init_request+0x346/0x380 fs/9p/vfs_addr.c:115
Code: ff ff 37 00 48 c1 e0 2a 48 8d 7b 40 48 89 fa 48 c1 ea 03 80 3c 02 00 75 35 48 8b 73 40 48 c7 c7 60 03 4e 8b e8 cb 20 12 fe 90 <0f> 0b 90 90 eb 9a e8 1f d0 ab fe e9 51 fe ff ff e8 25 cf ab fe e9
RSP: 0018:ffffc90006ebf2e8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff888029e72920 RCX: ffffffff8150eb39
RDX: ffff888018f42440 RSI: ffffffff8150eb46 RDI: 0000000000000001
RBP: ffff88805d9bfc00 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000000
R13: ffff88805d9bfd42 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff88802c400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000058389000 CR3: 0000000043388000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 netfs_alloc_request+0x54c/0x9a0 fs/netfs/objects.c:53
 netfs_write_back_from_locked_folio fs/netfs/buffered_write.c:910 [inline]
 netfs_writepages_begin fs/netfs/buffered_write.c:1100 [inline]
 netfs_writepages_region.constprop.0+0xffe/0x1bc0 fs/netfs/buffered_write.c:1123
 netfs_writepages+0x2fa/0x420 fs/netfs/buffered_write.c:1169
 do_writepages+0x1a3/0x7f0 mm/page-writeback.c:2612
 __writeback_single_inode+0x163/0xf90 fs/fs-writeback.c:1650
 writeback_sb_inodes+0x5a6/0x10d0 fs/fs-writeback.c:1941
 wb_writeback+0x28a/0xb30 fs/fs-writeback.c:2117
 wb_do_writeback fs/fs-writeback.c:2264 [inline]
 wb_workfn+0x28d/0xf40 fs/fs-writeback.c:2304
 process_one_work+0x902/0x1a30 kernel/workqueue.c:3254
 process_scheduled_works kernel/workqueue.c:3335 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
 </TASK>


---
This report 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 syzkaller@googlegroups.com.

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

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup