Re: [syzbot] [v9fs?] WARNING in v9fs_begin_writeback

[syzbot <syzbot+0b74d367d6e80661d6df@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in v9fs_begin_writeback

ino: ffff888032f426a0, inode fid list is empty: 1, v9fs_fid_find_inode
------------[ cut here ]------------
folio expected an open fid inode->i_ino=1901337
WARNING: CPU: 0 PID: 65 at fs/9p/vfs_addr.c:39 v9fs_begin_writeback fs/9p/vfs_addr.c:39 [inline]
WARNING: CPU: 0 PID: 65 at fs/9p/vfs_addr.c:39 v9fs_begin_writeback+0x210/0x280 fs/9p/vfs_addr.c:33
Modules linked in:
CPU: 0 UID: 0 PID: 65 Comm: kworker/u32:3 Not tainted 6.11.0-rc1-syzkaller-00154-gc0ecd6388360-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: writeback wb_workfn (flush-9p-76)
RIP: 0010:v9fs_begin_writeback fs/9p/vfs_addr.c:39 [inline]
RIP: 0010:v9fs_begin_writeback+0x210/0x280 fs/9p/vfs_addr.c:33
Code: 00 fc ff df 48 8b 5b 48 48 8d 7b 40 48 89 fa 48 c1 ea 03 80 3c 02 00 75 66 48 8b 73 40 48 c7 c7 20 9c 8e 8b e8 f1 49 0d fe 90 <0f> 0b 90 90 e9 62 ff ff ff e8 d2 2a a8 fe e9 51 ff ff ff e8 38 2a
RSP: 0018:ffffc90000d27480 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff888032f426a0 RCX: ffffffff814cc379
RDX: ffff88801b4d2440 RSI: ffffffff814cc386 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888030038048
R13: dffffc0000000000 R14: ffffc90000d27840 R15: ffff888030038298
FS:  0000000000000000(0000) GS:ffff88806b000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001000 CR3: 000000002aaca000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 netfs_writepages+0x656/0xde0 fs/netfs/write_issue.c:534
 do_writepages+0x1a3/0x7f0 mm/page-writeback.c:2683
 __writeback_single_inode+0x163/0xf90 fs/fs-writeback.c:1651
 writeback_sb_inodes+0x611/0x1150 fs/fs-writeback.c:1947
 wb_writeback+0x199/0xb50 fs/fs-writeback.c:2127
 wb_do_writeback fs/fs-writeback.c:2274 [inline]
 wb_workfn+0x28d/0xf40 fs/fs-writeback.c:2314
 process_one_work+0x9c5/0x1b40 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf20 kernel/workqueue.c:3390
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>


Tested on:

commit:         c0ecd638 Merge tag 'pci-v6.11-fixes-1' of git://git.ke..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=161d9755980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8da8b059e43c5370
dashboard link: https://syzkaller.appspot.com/bug?extid=0b74d367d6e80661d6df
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11272e5d980000