syzbot

syncing disks...panic: ffs_update: bad link cnt
Starting stack trace...
panic(ffffffff82836d7a) at panic+0x16f sys/kern/subr_prf.c:229
ffs_update(fffffd8066272890,0) at ffs_update+0x313 sys/ufs/ffs/ffs_inode.c:101
VOP_FSYNC(fffffd8067d5b990,fffffd807f7d77b8,2,ffff8000212f1b50) at VOP_FSYNC+0xd2 sys/kern/vfs_vops.c:311
ffs_sync_vnode(fffffd8067d5b990,ffff8000212e66e0) at ffs_sync_vnode+0x184 sys/ufs/ffs/ffs_vfsops.c:1197
vfs_mount_foreach_vnode(ffff8000006d8c00,ffffffff81869010,ffff8000212e66e0) at vfs_mount_foreach_vnode+0x55 sys/kern/vfs_subr.c:910
ffs_sync(ffff8000006d8c00,2,0,fffffd807f7d77b8,ffff8000212f1b50) at ffs_sync+0x11f sys/ufs/ffs/ffs_vfsops.c:1248
sys_sync(ffff8000212f1b50,0,0) at sys_sync+0xbc sys/kern/vfs_syscalls.c:537
vfs_syncwait(ffff8000212f1b50,1) at vfs_syncwait+0x3a
vfs_shutdown(ffff8000212f1b50) at vfs_shutdown+0x61 sys/kern/vfs_subr.c:1791
boot(100) at boot+0xcc sys/arch/amd64/amd64/machdep.c:843
reboot(100) at reboot+0x84
panic(ffffffff82787683) at panic+0x18f sys/kern/subr_prf.c:231
vop_generic_badop(ffff8000212e69a8) at vop_generic_badop+0x1f sys/kern/vfs_default.c:133
VOP_STRATEGY(fffffd8067ccd7d0,fffffd8067a3e7e0) at VOP_STRATEGY+0x9f sys/kern/vfs_vops.c:628
bwrite(fffffd8067a3e7e0) at bwrite+0x1f4 sys/kern/vfs_bio.c:760
VOP_BWRITE(fffffd8067a3e7e0) at VOP_BWRITE+0x4e sys/kern/vfs_vops.c:640
ufs_mkdir(ffff8000212e6c40) at ufs_mkdir+0x6c4 sys/ufs/ufs/ufs_vnops.c:1235
VOP_MKDIR(fffffd8067ab48a0,ffff8000212e6da0,ffff8000212e6dd0,ffff8000212e6cd0) at VOP_MKDIR+0xc3 sys/kern/vfs_vops.c:388
domkdirat(ffff8000212f1b50,ffffff9c,7428e0617130,1ff) at domkdirat+0x125 sys/kern/vfs_syscalls.c:3074
syscall(ffff8000212e6f50) at syscall+0x5e2 mi_syscall sys/sys/syscall_mi.h:110 [inline]
syscall(ffff8000212e6f50) at syscall+0x5e2 sys/arch/amd64/amd64/trap.c:632
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7428e06171a0, count: 236
End of stack trace.

dump to dev 4,1 not possible
rpanebioco:t iknegr.nel..
 diagnosticSeaBIOS (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 68bf758f-d7e1-83a6-91e2-c70932eb46bc
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 0x000f2850: 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 3.56
boot> set $lines = 0
set: syntax error
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