panic: ffs2_balloc: unwind failed (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c4a497a8c849 stray newline
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=13db1ee2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1bc15e68cd2a49e5
dashboard link: https://syzkaller.appspot.com/bug?extid=d9000fd290e5d5d042da

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ad3edb67ee95/disk-c4a497a8.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/f5dc669682b0/bsd-c4a497a8.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c2c744fd036b/kernel-c4a497a8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d9000f...@syzkaller.appspotmail.com

panic: ffs2_balloc: unwind failed
Starting stack trace...
panic(ffffffff832dd33e) at panic+0x1ba sys/kern/subr_prf.c:229
ffs2_balloc(fffffd806aa36d00,6001000003,1,fffffd8007bfb7b8,1,ffff80003a92f5c0) at ffs2_balloc+0x1965
ffs_truncate(fffffd806aa36d00,6001000004,0,fffffd8007bfb7b8) at ffs_truncate+0x4f8 sys/ufs/ffs/ffs_inode.c:217
ufs_setattr(ffff80003a92f6e0) at ufs_setattr+0x8e0 sys/ufs/ufs/ufs_vnops.c:403
VOP_SETATTR(fffffd8068a36c00,ffff80003a92f768,fffffd8007bfb7b8,ffff80003a936558) at VOP_SETATTR+0x112 sys/kern/vfs_vops.c:210
dotruncate(ffff80003a936558,fffffd8068a36c00,6001000004) at dotruncate+0x1da sys/kern/vfs_syscalls.c:2865
sys_truncate(ffff80003a936558,ffff80003a92fa30,ffff80003a92f980) at sys_truncate+0x13e sys/kern/vfs_syscalls.c:2889
syscall(ffff80003a92fa30) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003a92fa30) at syscall+0x962 sys/arch/amd64/amd64/trap.c:748
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x345da019890, count: 248
End of stack trace.


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