[v6.1] kernel BUG in balance_leaf (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 50cbba13faa2 Linux 6.1.159
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13ba862a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31ea1cecaf34f0db
dashboard link: https://syzkaller.appspot.com/bug?extid=b017341f630a94cd6e1b
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ad0bd66715a/disk-50cbba13.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3284d626258e/vmlinux-50cbba13.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a1f92ca7bbfc/Image-50cbba13.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b01734...@syzkaller.appspotmail.com

REISERFS warning (device loop2): vs-13060 reiserfs_update_sd_size: stat data of object [2 6 0x0 SD] (nlink == 1) not found (pos 1)
REISERFS panic (device loop2): vs-12195 balance_leaf: CFR not initialized
------------[ cut here ]------------
kernel BUG at fs/reiserfs/prints.c:390!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4471 Comm: syz.2.3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : __reiserfs_panic+0x13c/0x140 fs/reiserfs/prints.c:384
lr : __reiserfs_panic+0x13c/0x140 fs/reiserfs/prints.c:384
sp : ffff8000210e64c0
x29: ffff8000210e6560 x28: ffff8000210e6d60 x27: ffff8000210e6d78
x26: ffff0000f7b9f027 x25: dfff800000000000 x24: ffff8000210e6f00
x23: ffff8000210e64e0 x22: ffff800011b5eba0 x21: ffff0000f611a000
x20: ffff800011b5eb80 x19: ffff800014770cbe x18: ffff800011a5bd40
x17: 6e6920746f6e2052 x16: ffff8000082d3a08 x15: 0000000000000002
x14: 00000000ffffffff x13: 0000000000000001 x12: 0000000000080000
x11: 000000000002808b x10: ffff800027029000 x9 : e2f74d8c1357c300
x8 : e2f74d8c1357c300 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000210e5f98 x4 : ffff800015134e00 x3 : ffff800008313428
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000049
Call trace:
__reiserfs_panic+0x13c/0x140 fs/reiserfs/prints.c:384
balance_leaf+0xa0a8/0xd2f4 fs/reiserfs/do_balan.c:1439
do_balance+0x260/0x774 fs/reiserfs/do_balan.c:1888
reiserfs_paste_into_item+0x5b4/0x6d0 fs/reiserfs/stree.c:2159
reiserfs_get_block+0x1444/0x3524 fs/reiserfs/inode.c:1069
__block_write_begin_int+0x34c/0x13b8 fs/buffer.c:1991
__block_write_begin+0x7c/0xa0 fs/buffer.c:2041
reiserfs_write_begin+0x328/0x71c fs/reiserfs/inode.c:2775
generic_perform_write+0x230/0x4e4 mm/filemap.c:3862
__generic_file_write_iter+0x130/0x250 mm/filemap.c:3960
generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:3989
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x5ac/0x7c4 fs/read_write.c:584
ksys_write+0x120/0x210 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: 912d80a5 911aa2a1 aa1303e4 97ffe397 (d4210000)
---[ end trace 0000000000000000 ]---


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