[syzbot] [f2fs?] kernel BUG in f2fs_write_end_bio

[syzbot] [f2fs?] kernel BUG in f2fs_write_end_bio

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    fe2ec83746e5 Merge tag 'hid-for-linus-2026092202' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13ba8d25580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2b924f079099ba6e
dashboard link: https://syzkaller.appspot.com/bug?extid=eae639926b1c1ac725d5
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-fe2ec837.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/64158d6729cc/vmlinux-fe2ec837.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4e2043b7fc3f/bzImage-fe2ec837.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eae639926b1c1ac725d5@syzkaller.appspotmail.com

F2FS-fs (loop0): inconsistent node block, node_type:0, nid:3, node_footer[nid:0,ino:0,ofs:0,cpver:0,blkaddr:0]
------------[ cut here ]------------
kernel BUG at fs/f2fs/data.c:365!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 1055 Comm: kworker/u4:9 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: loop0 loop_workfn
RIP: 0010:f2fs_write_end_bio+0x167d/0x16e0 fs/f2fs/data.c:365
Code: 67 5f 8c e8 75 15 c1 fc 90 0f 0b e8 1d e0 60 fd 48 8b 7c 24 08 48 c7 c6 20 67 5f 8c e8 5c 15 c1 fc 90 0f 0b e8 04 e0 60 fd 90 <0f> 0b e8 fc df 60 fd 48 8b 7c 24 08 48 c7 c6 20 67 5f 8c e8 3b 15
RSP: 0018:ffffc9000527f490 EFLAGS: 00010293
RAX: ffffffff84670d0c RBX: 0000000000000003 RCX: ffff888036980000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: ffffea00010bb900 R08: ffffffff907a767f R09: 1ffffffff20f4ecf
R10: dffffc0000000000 R11: fffffbfff20f4ed0 R12: ffffea00010bb8c0
R13: dffffc0000000000 R14: 0000000000001000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88808c2c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcdf33c4d10 CR3: 000000003b2bb000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 blk_update_request+0x57b/0xe50 block/blk-mq.c:1016
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1147
 lo_rw_aio_complete drivers/block/loop.c:338 [inline]
 lo_rw_aio+0xcd4/0xf20 drivers/block/loop.c:406
 do_req_filebacked drivers/block/loop.c:430 [inline]
 loop_handle_cmd drivers/block/loop.c:1949 [inline]
 loop_process_work+0x621/0x11c0 drivers/block/loop.c:1984
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_write_end_bio+0x167d/0x16e0 fs/f2fs/data.c:365
Code: 67 5f 8c e8 75 15 c1 fc 90 0f 0b e8 1d e0 60 fd 48 8b 7c 24 08 48 c7 c6 20 67 5f 8c e8 5c 15 c1 fc 90 0f 0b e8 04 e0 60 fd 90 <0f> 0b e8 fc df 60 fd 48 8b 7c 24 08 48 c7 c6 20 67 5f 8c e8 3b 15
RSP: 0018:ffffc9000527f490 EFLAGS: 00010293
RAX: ffffffff84670d0c RBX: 0000000000000003 RCX: ffff888036980000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: ffffea00010bb900 R08: ffffffff907a767f R09: 1ffffffff20f4ecf
R10: dffffc0000000000 R11: fffffbfff20f4ed0 R12: ffffea00010bb8c0
R13: dffffc0000000000 R14: 0000000000001000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88808c2c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcdf33c4d10 CR3: 000000001f6d9000 CR4: 0000000000352ef0


---
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