[syzbot] [nilfs?] kernel BUG in nilfs_copy_dirty_pages

[syzbot <syzbot+8baf9a79a3ffc6271cb6@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    3036cd0d3328 Merge tag 'ata-7.0-final' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12718eba580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d46eab0cfd31c214
dashboard link: https://syzkaller.appspot.com/bug?extid=8baf9a79a3ffc6271cb6
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 (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-3036cd0d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/52b4694b61e7/vmlinux-3036cd0d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3cae4a12f2ba/bzImage-3036cd0d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8baf9a79a3ffc6271cb6@syzkaller.appspotmail.com

NILFS (loop0): mounting fs with errors
Buffer I/O error on dev loop0, logical block 1, lost sync page write
NILFS (loop0): unable to write superblock: err=-5
NILFS_FOLIO_BUG(ffffea00010c5f40): cnt=3 index#=0 flags=0x4fff38000004225 mapping=ffff888055c549c8 ino=3
 BH[0] ffff888046f3b488: cnt=1 block#=42 state=0x1b
 BH[1] ffff888046f3b570: cnt=1 block#=43 state=0x1b
 BH[2] ffff888046f3b658: cnt=1 block#=44 state=0x19
 BH[3] ffff888046f3b740: cnt=0 block#=18446744073709551615 state=0x0
------------[ cut here ]------------
kernel BUG at fs/nilfs2/page.c:262!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 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
RIP: 0010:nilfs_copy_dirty_pages+0x5af/0x610 fs/nilfs2/page.c:262
Code: 41 5d 41 5e 41 5f 5d e9 4f b2 07 08 cc e8 19 d9 18 fe e9 67 ff ff ff e8 ff ca 04 08 e8 0a d9 18 fe 4c 89 e7 e8 f2 f7 ff ff 90 <0f> 0b e8 fa d8 18 fe 4c 89 e7 48 c7 c6 20 85 10 8c e8 bb 24 7b fd
RSP: 0018:ffffc9000cc774e0 EFLAGS: 00010283
RAX: ffffffff83acf054 RBX: 0000000000000000 RCX: 0000000000100000
RDX: ffffc90020001000 RSI: 0000000000001f7b RDI: 0000000000001f7c
RBP: ffffc9000cc776f8 R08: ffffc9000cc77227 R09: 1ffff9200198ee44
R10: dffffc0000000000 R11: fffff5200198ee45 R12: ffffea00010c5f40
R13: 0000000000000001 R14: dffffc0000000000 R15: ffffea00010c5f48
FS:  00007f05fddc96c0(0000) GS:ffff88808ca49000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f05f0fff000 CR3: 0000000040acc000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 nilfs_mdt_save_to_shadow_map+0xbb/0x1c0 fs/nilfs2/mdt.c:554
 nilfs_clean_segments+0x162/0xa50 fs/nilfs2/segment.c:2521
 nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:916 [inline]
 nilfs_ioctl+0x261f/0x2780 fs/nilfs2/ioctl.c:1346
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f05fcf9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f05fddc8fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f05fd216090 RCX: 00007f05fcf9c819
RDX: 0000200000000640 RSI: 0000000040786e88 RDI: 000000000000000c
RBP: 00007f05fd032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f05fd216128 R14: 00007f05fd216090 R15: 00007ffedc700128
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_copy_dirty_pages+0x5af/0x610 fs/nilfs2/page.c:262
Code: 41 5d 41 5e 41 5f 5d e9 4f b2 07 08 cc e8 19 d9 18 fe e9 67 ff ff ff e8 ff ca 04 08 e8 0a d9 18 fe 4c 89 e7 e8 f2 f7 ff ff 90 <0f> 0b e8 fa d8 18 fe 4c 89 e7 48 c7 c6 20 85 10 8c e8 bb 24 7b fd
RSP: 0018:ffffc9000cc774e0 EFLAGS: 00010283
RAX: ffffffff83acf054 RBX: 0000000000000000 RCX: 0000000000100000
RDX: ffffc90020001000 RSI: 0000000000001f7b RDI: 0000000000001f7c
RBP: ffffc9000cc776f8 R08: ffffc9000cc77227 R09: 1ffff9200198ee44
R10: dffffc0000000000 R11: fffff5200198ee45 R12: ffffea00010c5f40
R13: 0000000000000001 R14: dffffc0000000000 R15: ffffea00010c5f48
FS:  00007f05fddc96c0(0000) GS:ffff88808ca49000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fd031e8168 CR3: 0000000040acc000 CR4: 0000000000352ef0


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