syzbot

syncing disks...panic: ffs_update: bad link cnt
Starting stack trace...
panic(ffffffff828c30cb) at panic+0x159 sys/kern/subr_prf.c:229
ffs_update(fffffd8068d425b0,0) at ffs_update+0x2da sys/ufs/ffs/ffs_inode.c:99
VOP_FSYNC(fffffd806a055960,fffffd807f7d74e0,2,ffff80002a6d59c8) at VOP_FSYNC+0xc9 sys/kern/vfs_vops.c:311
ffs_sync_vnode(fffffd806a055960,ffff80002daf4c68) at ffs_sync_vnode+0x16b sys/ufs/ffs/ffs_vfsops.c:1081
vfs_mount_foreach_vnode(ffff8000006cf000,ffffffff8129b640,ffff80002daf4c68) at vfs_mount_foreach_vnode+0x55 sys/kern/vfs_subr.c:910
ffs_sync(ffff8000006cf000,2,0,fffffd807f7d74e0,ffff80002a6d59c8) at ffs_sync+0x104 sys/ufs/ffs/ffs_vfsops.c:1131
sys_sync(ffff80002a6d59c8,0,0) at sys_sync+0xbc sys/kern/vfs_syscalls.c:537
vfs_syncwait(ffff80002a6d59c8,1) at vfs_syncwait+0x3b
vfs_shutdown(ffff80002a6d59c8) at vfs_shutdown+0x61 sys/kern/vfs_subr.c:1791
boot(100) at boot+0xe0 sys/arch/amd64/amd64/machdep.c:900
reboot(100) at reboot+0x7b
panic(ffffffff8286e4b0) at panic+0x179 sys/kern/subr_prf.c:231
vop_generic_badop(ffff80002daf4f28) at vop_generic_badop+0x1f sys/kern/vfs_default.c:133
VOP_STRATEGY(fffffd807695d890,fffffd80758af8f8) at VOP_STRATEGY+0x9f sys/kern/vfs_vops.c:634
bwrite(fffffd80758af8f8) at bwrite+0x1ca sys/kern/vfs_bio.c:757
VOP_BWRITE(fffffd80758af8f8) at VOP_BWRITE+0x4e sys/kern/vfs_vops.c:646
ufs_mkdir(ffff80002daf51a0) at ufs_mkdir+0x445 sys/ufs/ufs/ufs_vnops.c:1160
VOP_MKDIR(fffffd8071794958,ffff80002daf5300,ffff80002daf5330,ffff80002daf5230) at VOP_MKDIR+0xc3 sys/kern/vfs_vops.c:394
domkdirat(ffff80002a6d59c8,ffffff9c,7ae2f1b91c20,1ff) at domkdirat+0x125 sys/kern/vfs_syscalls.c:3104
syscall(ffff80002daf54b0) at syscall+0x72a sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7ae2f1b91c90, count: 236
End of stack trace.

dump to dev 4,1 not possible
rebooting...
SeaBIOS (version 1.8.2-google)
Total RAM Size = 0x0000000080000000 = 2048 MiB
CPUs found: 2     Max CPUs supported: 2
SeaBIOS (version 1.8.2-google)
Machine UUID 0fee9609-1d66-d0cb-3385-b9d53e0469ef
found virtio-scsi at 0:3
virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0
virtio-scsi blksize=512 sectors=4194304 = 2048 MiB
drive 0x000f27c0: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Sending Seabios boot VM event.
Booting from Hard Disk 0...
>> OpenBSD/amd64 BOOT 3.65
boot> set $maxwidth = 0
set: syntax error
boot> show panic
boot: illegal argument panic
boot> trace
boot> show registers
boot> show proc
boot> ps
boot> show all locks
boot> show malloc
boot> show all pools
boot> machine ddbcpu 0
machine: syntax error
boot> trace
boot> machine ddbcpu 1
machine: syntax error
boot> trace