witness: lock order reversal:
 1st 0xfffffd806c5e7f10 vmmaplk (&map->lock)
 2nd 0xfffffd806ded3918 inode (&ip->i_lock)
lock order [1] vmmaplk (&map->lock) -> [2] inode (&ip->i_lock)
#0  rw_enter+0x122
#1  rrw_enter+0xbe sys/kern/kern_rwlock.c:464
#2  VOP_LOCK+0xa6 sys/kern/vfs_vops.c:524
#3  vn_lock+0xa4 sys/kern/vfs_vnops.c:564
#4  vn_rdwr+0xd1 sys/kern/vfs_vnops.c:320
#5  vndstrategy+0x4ff sys/dev/vnd.c:342
#6  physio+0x2f6 sys/kern/kern_physio.c:162
#7  spec_write+0x120 sys/kern/spec_vnops.c:302
#8  VOP_WRITE+0x102 sys/kern/vfs_vops.c:245
#9  vn_write+0x1d1 sys/kern/vfs_vnops.c:408
#10 dofilewritev+0x23c sys/kern/sys_generic.c:380
#11 sys_writev+0xd8 sys/kern/sys_generic.c:327
#12 syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:178 [inline]
#12 syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577
#13 Xsyscall+0x128
lock order [2] inode (&ip->i_lock) -> [1] vmmaplk (&map->lock)
#0  rw_enter_read+0xab sys/kern/kern_rwlock.c:112
#1  uvmfault_lookup+0x122 sys/uvm/uvm_fault.c:1819
#2  uvm_fault_check+0x49 sys/uvm/uvm_fault.c:672
#3  uvm_fault+0xf5 sys/uvm/uvm_fault.c:600
#4  kpageflttrap+0x2d0 sys/arch/amd64/amd64/trap.c:279
#5  kerntrap+0x14a sys/arch/amd64/amd64/trap.c:332
#6  alltraps_kern_meltdown+0x7b
#7  copyout+0x57
#8  ffs_read+0x422 sys/ufs/ffs/ffs_vnops.c:254
#9  VOP_READ+0x102 sys/kern/vfs_vops.c:227
#10 vn_rdwr+0x15b
#11 vmcmd_map_readvn+0x142 sys/kern/exec_subr.c:249
#12 exec_process_vmcmds+0xfb sys/kern/exec_subr.c:139
#13 sys_execve+0xbe4 sys/kern/kern_exec.c:468
#14 start_init+0x3c6 sys/kern/init_main.c:714
#15 proc_trampoline+0x10
Stopped at      db_enter+0x25:  addq    $0x8,%rsp