[syzbot] [netfs?] WARNING in netfs_writepages

[syzbot <syzbot+06023121b0153752a3d3@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    f1b785f4c787 Merge tag 'for_linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11f5ace8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=327b6119dd928cbc
dashboard link: https://syzkaller.appspot.com/bug?extid=06023121b0153752a3d3
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2eb65d2a03c1/disk-f1b785f4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/70c538f32a8e/vmlinux-f1b785f4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/79fc36f9a44b/bzImage-f1b785f4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+06023121b0153752a3d3@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 35 at fs/netfs/write_issue.c:573 netfs_writepages+0x350/0x9d0 fs/netfs/write_issue.c:573
Modules linked in:
CPU: 0 UID: 0 PID: 35 Comm: kworker/u8:2 Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Workqueue: writeback wb_workfn
 (flush-9p-3)

RIP: 0010:netfs_writepages+0x350/0x9d0 fs/netfs/write_issue.c:573
Code: d5 05 00 00 4c 8b a5 90 02 00 00 4c 89 fe 48 c1 e6 0c 4c 89 e7 e8 00 04 54 ff 48 8b 44 24 10 49 39 c4 7e 09 e8 41 02 54 ff 90 <0f> 0b 90 e8 38 02 54 ff 48 8d 7b 28 48 89 f8 48 c1 e8 03 42 80 3c
RSP: 0018:ffffc90000ab7400 EFLAGS: 00010293

RAX: 0000000000000000 RBX: ffffea00015c0700 RCX: ffffffff82397910
RDX: ffff88801e292440 RSI: ffffffff8239791f RDI: 0000000000000006
RBP: ffff88802aac0000 R08: 0000000000000006 R09: 0000000000000000
R10: 810f000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffffc90000ab7790 R14: dffffc0000000000 R15: 000810f000000000
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc1ba1a2d3d CR3: 000000003660a000 CR4: 00000000003526f0
DR0: 0000000000000003 DR1: 0000000000000004 DR2: 0000000100000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 do_writepages+0x1a3/0x7f0 mm/page-writeback.c:2683
 __writeback_single_inode+0x166/0xfa0 fs/fs-writeback.c:1658
 writeback_sb_inodes+0x603/0xfa0 fs/fs-writeback.c:1954
 __writeback_inodes_wb+0xff/0x2e0 fs/fs-writeback.c:2025
 wb_writeback+0x721/0xb50 fs/fs-writeback.c:2136
 wb_check_old_data_flush fs/fs-writeback.c:2240 [inline]
 wb_do_writeback fs/fs-writeback.c:2293 [inline]
 wb_workfn+0x8c3/0xbc0 fs/fs-writeback.c:2321
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 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>


---
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