[syzbot] [f2fs?] kernel BUG in f2fs_put_super (5)

[syzbot] [f2fs?] kernel BUG in f2fs_put_super (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    ec8957276674 Merge tag 'hwmon-for-v7.1-rc3' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1030f1ce580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f2e8ebfec4636d32
dashboard link: https://syzkaller.appspot.com/bug?extid=8b8205b83afd5cbdabaf
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cd85c29cb989/disk-ec895727.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/753d9d274777/vmlinux-ec895727.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3f65991d8333/bzImage-ec895727.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8b8205b83afd5cbdabaf@syzkaller.appspotmail.com

F2FS-fs (loop3): Stopped filesystem due to reason: 3
F2FS-fs (loop3): detect filesystem reference count leak during umount, type: 2, count: -1
------------[ cut here ]------------
kernel BUG at fs/f2fs/super.c:2061!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 5607 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:f2fs_put_super+0x1451/0x1460 fs/f2fs/super.c:2061
Code: fd 41 bf 0d 00 00 00 4c 89 ef 44 89 fe e8 47 3f 00 00 4c 89 ef 31 f6 48 c7 c2 40 04 9b 8b 44 89 f9 49 89 c0 e8 80 4a fd ff 90 <0f> 0b 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffc90004f67900 EFLAGS: 00010246
RAX: c02b1e247a139300 RBX: 1ffff11007f8a85a RCX: c02b1e247a139300
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90004f67b58 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff520009ecea9 R12: dffffc0000000000
R13: ffff88803fc54000 R14: 00000000ffffffff R15: 0000000000000002
FS:  000055555e19c500(0000) GS:ffff888126276000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1d7b1dc000 CR3: 000000003f6c6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 kill_f2fs_super+0x402/0x730 fs/f2fs/super.c:5534
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xf3/0x4d0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5dfa74e017
Code: a2 c7 05 dc 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffea8646e48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5dfa7e2120 RCX: 00007f5dfa74e017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffea8646f00
RBP: 00007ffea8646f00 R08: 00007ffea8647f00 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffea8647f90
R13: 00007f5dfa7e2120 R14: 00000000000438b6 R15: 00007ffea8647fd0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_put_super+0x1451/0x1460 fs/f2fs/super.c:2061
Code: fd 41 bf 0d 00 00 00 4c 89 ef 44 89 fe e8 47 3f 00 00 4c 89 ef 31 f6 48 c7 c2 40 04 9b 8b 44 89 f9 49 89 c0 e8 80 4a fd ff 90 <0f> 0b 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffc90004f67900 EFLAGS: 00010246
RAX: c02b1e247a139300 RBX: 1ffff11007f8a85a RCX: c02b1e247a139300
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90004f67b58 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff520009ecea9 R12: dffffc0000000000
R13: ffff88803fc54000 R14: 00000000ffffffff R15: 0000000000000002
FS:  000055555e19c500(0000) GS:ffff888126276000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1d7b1dc000 CR3: 000000003f6c6000 CR4: 00000000003526f0


---
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