[v6.6] WARNING in nilfs_segctor_do_construct

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9760bf04666d Linux 6.6.135
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12725e6a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link: https://syzkaller.appspot.com/bug?extid=20ffb10c65422a9e0e7d
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/a685913d05a7/disk-9760bf04.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a3c1d21d4bca/vmlinux-9760bf04.xz
kernel image: https://storage.googleapis.com/syzbot-assets/09178887ef0d/bzImage-9760bf04.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+20ffb1...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 6311 at fs/buffer.c:1188 mark_buffer_dirty+0x2bb/0x4c0 fs/buffer.c:1188
Modules linked in:
CPU: 1 PID: 6311 Comm: segctord Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:mark_buffer_dirty+0x2bb/0x4c0 fs/buffer.c:1188
Code: 00 00 00 5b 41 5c 41 5e 41 5f 5d e9 9f 9a fc ff e8 5a b6 88 ff 48 89 df 5b 41 5c 41 5e 41 5f 5d e9 ea 08 e8 ff e8 45 b6 88 ff <0f> 0b e9 84 fd ff ff e8 39 b6 88 ff 0f 0b e9 b0 fd ff ff e8 2d b6
RSP: 0018:ffffc9000c7876f0 EFLAGS: 00010293
RAX: ffffffff81fe6bbb RBX: ffff888057c14bc8 RCX: ffff8880212fbc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc9000c787b01 R08: ffff888057c14bcf R09: 1ffff1100af82979
R10: dffffc0000000000 R11: ffffed100af8297a R12: 1ffff1100bc2675c
R13: ffff88805e133af0 R14: ffff88805f091328 R15: 1ffff1100bc2675e
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000002f3030 CR3: 000000005d49f000 CR4: 00000000003506e0
Call Trace:
<TASK>
nilfs_segctor_collect_dirty_files fs/nilfs2/segment.c:2009 [inline]
nilfs_segctor_do_construct+0x307/0x68a0 fs/nilfs2/segment.c:2071
nilfs_segctor_construct+0x17b/0x690 fs/nilfs2/segment.c:2454
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2562 [inline]
nilfs_segctor_thread+0x536/0x10d0 fs/nilfs2/segment.c:2646
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 9760bf04666d Linux 6.6.135
git tree: linux-6.6.y

console output: https://syzkaller.appspot.com/x/log.txt?x=11e152d2580000

kernel config: https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link: https://syzkaller.appspot.com/bug?extid=20ffb10c65422a9e0e7d
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1579f702580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15e152d2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a685913d05a7/disk-9760bf04.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a3c1d21d4bca/vmlinux-9760bf04.xz
kernel image: https://storage.googleapis.com/syzbot-assets/09178887ef0d/bzImage-9760bf04.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/07227049be0b/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+20ffb1...@syzkaller.appspotmail.com

------------[ cut here ]------------

WARNING: CPU: 0 PID: 5928 at fs/buffer.c:1188 mark_buffer_dirty+0x2bb/0x4c0 fs/buffer.c:1188
Modules linked in:
CPU: 0 PID: 5928 Comm: segctord Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:mark_buffer_dirty+0x2bb/0x4c0 fs/buffer.c:1188
Code: 00 00 00 5b 41 5c 41 5e 41 5f 5d e9 9f 9a fc ff e8 5a b6 88 ff 48 89 df 5b 41 5c 41 5e 41 5f 5d e9 ea 08 e8 ff e8 45 b6 88 ff <0f> 0b e9 84 fd ff ff e8 39 b6 88 ff 0f 0b e9 b0 fd ff ff e8 2d b6

RSP: 0018:ffffc900034876f0 EFLAGS: 00010293
RAX: ffffffff81fe6bbb RBX: ffff888059e41000 RCX: ffff88807a4c3c00

RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002

RBP: ffffc90003487b01 R08: ffff888059e41007 R09: 1ffff1100b3c8200
R10: dffffc0000000000 R11: ffffed100b3c8201 R12: 1ffff1100b3c275c
R13: ffff888059e13af0 R14: ffff88802e69c328 R15: 1ffff1100b3c275e
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f2a97e66aa2 CR3: 000000007832c000 CR4: 00000000003506f0

Call Trace:
<TASK>
nilfs_segctor_collect_dirty_files fs/nilfs2/segment.c:2009 [inline]
nilfs_segctor_do_construct+0x307/0x68a0 fs/nilfs2/segment.c:2071
nilfs_segctor_construct+0x17b/0x690 fs/nilfs2/segment.c:2454
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2562 [inline]
nilfs_segctor_thread+0x536/0x10d0 fs/nilfs2/segment.c:2646
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>


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