panic: trap type 4, code=0, pc=ffffffff81da3a9e
Starting stack trace...
panic(ffffffff827993ad) at panic+0x16f sys/kern/subr_prf.c:229
kerntrap(ffff8000297dd6c0) at kerntrap+0x1d7 sys/arch/amd64/amd64/trap.c:327
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
ktrops(ffff8000212b1358,dead4110dead4110,0,80000038,fffffd80764cecd8,fffffd807f7d7548) at ktrops+0x4e ktrcanset sys/kern/kern_ktrace.c:700 [inline]
ktrops(ffff8000212b1358,dead4110dead4110,0,80000038,fffffd80764cecd8,fffffd807f7d7548) at ktrops+0x4e sys/kern/kern_ktrace.c:543
doktrace(fffffd80764cecd8,4,38,0,ffff8000212b1358) at doktrace+0x524 ktrsetchildren sys/kern/kern_ktrace.c:568 [inline]
doktrace(fffffd80764cecd8,4,38,0,ffff8000212b1358) at doktrace+0x524 sys/kern/kern_ktrace.c:490
sys_ktrace(ffff8000212b1358,ffff8000297dda00,ffff8000297dda50) at sys_ktrace+0xd6 sys/kern/kern_ktrace.c:531
syscall(ffff8000297ddad0) at syscall+0x5e2 mi_syscall sys/sys/syscall_mi.h:110 [inline]
syscall(ffff8000297ddad0) at syscall+0x5e2 sys/arch/amd64/amd64/trap.c:623
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x298c7aadc70, count: 249
End of stack trace.
syncing disks...panic: kernel diagnostic assertion "((flags & PGO_LOCKED) != 0 && rw_lock_held(uobj->vmobjlock)) || (flags & PGO_LOCKED) == 0" failed: file "/syzkaller/managers/multicore/kernel/sys/uvm/uvm_vnode.c", line 953
Starting stack trace...
panic(ffffffff827a213a) at panic+0x16f sys/kern/subr_prf.c:229
__assert(ffffffff8281ee9f,ffffffff827934d0,3b9,ffffffff8277adfe) at __assert+0x29 sys/kern/subr_prf.c:157
uvn_get(fffffd8069956b58,0,ffff8000212bd820,ffff8000212bd694,0,2,52861ee454b45e0e,fffffd8069956b58) at uvn_get+0x4b6 sys/uvm/uvm_vnode.c:952
uvm_fault_lower_lookup(ffff8000212bd8a0,ffff8000212bd8d8,ffff8000212bd820) at uvm_fault_lower_lookup+0xf7 sys/uvm/uvm_fault.c:1129
uvm_fault_lower(ffff8000212bd8a0,ffff8000212bd8d8,ffff8000212bd820,0) at uvm_fault_lower+0x63 sys/uvm/uvm_fault.c:1228
uvm_fault(fffffd8078818580,219ae2000,0,2) at uvm_fault+0x238
upageflttrap(ffff8000212bda20,219ae2000) at upageflttrap+0x86 sys/arch/amd64/amd64/trap.c:188
usertrap(ffff8000212bda20) at usertrap+0x226 sys/arch/amd64/amd64/trap.c:436
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0xc000355628, count: 248
End of stack trace.

dump to dev 4,1 not possible
rpaebnoic:o tkeinrgn.e.l. 
diagnostic asSeaBIOS (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 50375c3b-e826-8a7e-06ca-b163c863336b
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 0x000f2880: 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 $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