witness: lock order reversal:
 1st 0xffff80000160fcb0 sbufsnd (&so->so_snd.sb_lock)
 2nd 0xfffffd807d327568 inode (&ip->i_lock)
lock order [1] sbufsnd (&so->so_snd.sb_lock) -> [2] inode (&ip->i_lock)
lock order data 0xffffffff835040fc -> 0xffffffff8347bc4f is missing
lock order [2] inode (&ip->i_lock) -> [3] sbufrcv (&so->so_rcv.sb_lock)
#0  rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234
#1  sblock+0xb6 sys/kern/uipc_socket2.c:536
#2  soreceive+0x27d sys/kern/uipc_socket.c:890
#3  fifo_read+0x117 sys/miscfs/fifofs/fifo_vnops.c:264
#4  VOP_READ+0x101 sys/kern/vfs_vops.c:227
#5  vn_rdwr+0x15b sys/kern/vfs_vnops.c:-1
#6  vndsetcred+0xa1 sys/dev/vnd.c:685
#7  vndioctl+0xdfc sys/dev/vnd.c:486
#8  VOP_IOCTL+0xac sys/kern/vfs_vops.c:264
#9  vn_ioctl+0xf8 sys/kern/vfs_vnops.c:537
#10 sys_ioctl+0x674 sys/kern/sys_generic.c:-1
#11 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#11 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
#12 Xsyscall+0x128
lock order [3] sbufrcv (&so->so_rcv.sb_lock) -> [1] sbufsnd (&so->so_snd.sb_lock)
#0  rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234
#1  sblock+0xb6 sys/kern/uipc_socket2.c:536
#2  sosplice+0x312 sys/kern/uipc_socket.c:1347
#3  sys_setsockopt+0x2ba sys/kern/uipc_syscalls.c:1226
#4  syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#4  syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
#5  Xsyscall+0x128
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
ddb{1}> 
ddb{1}> set $lines = 0
ddb{1}> set $maxwidth = 0
ddb{1}> show panic
the kernel did not panic
ddb{1}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
witness_checkorder(fffffd807d327568,9,0) at witness_checkorder+0x10d1 sys/kern/subr_witness.c:-1
rw_do_enter_write(fffffd807d327550,1) at rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234
rrw_enter(fffffd807d327550,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
VOP_LOCK(fffffd806e9debd0,2001) at VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
vn_lock(fffffd806e9debd0,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:576
vget(fffffd806e9debd0,2001) at vget+0x2a2 sys/kern/vfs_subr.c:686
ktrwriteraw(ffff80003c3d74e8,fffffd806e9debd0,fffffd80097fd5b0,ffff80003c3c43a0,ffff80003c3c4380) at ktrwriteraw+0x175 sys/kern/kern_ktrace.c:689
ktrnamei(ffff80003c3d74e8,ffff80002a214400) at ktrnamei+0x145 ktrwrite sys/kern/kern_ktrace.c:-1 [inline]
ktrnamei(ffff80003c3d74e8,ffff80002a214400) at ktrnamei+0x145 sys/kern/kern_ktrace.c:222
namei(ffff80003c3c44f0) at namei+0x29e sys/kern/vfs_lookup.c:170
unp_connect(ffff80000160fac8,fffffd807ea10200,ffff80003c3d74e8) at unp_connect+0x29d sys/kern/uipc_usrreq.c:872
uipc_dgram_send(ffff80000160fac8,fffffd806c22f000,fffffd807ea10200,0) at uipc_dgram_send+0x163 sys/kern/uipc_usrreq.c:609
sosend(ffff80000160fac8,fffffd807ea10200,ffff80003c3c4778,0,0,402) at sosend+0x804 sys/kern/uipc_socket.c:-1
sendit(ffff80003c3d74e8,5,ffff80003c3c48f0,402,ffff80003c3c4928) at sendit+0x5a5 sys/kern/uipc_syscalls.c:785
sys_sendmmsg(ffff80003c3d74e8,ffff80003c3c4aa0,ffff80003c3c49f0) at sys_sendmmsg+0x3f3 sys/kern/uipc_syscalls.c:676
syscall(ffff80003c3c4aa0) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c3c4aa0) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x521afcb0ac0, count: -17
ddb{1}> show registers
rdi                                0
rsi                                0
rbp               0xffff80003c3c4000
rbx                                0
rdx                                0
rcx               0xffff80003c3d74e8
rax               0xffff80002999dff0
r8                0xffff80003c3c3ee0
r9                0x8080808080808080
r10                0x9af14d5c9c3b7a7
r11               0x12f6db7e936e9ce9
r12               0xfffffd80040ac8c0
r13               0xfffffd80048940a8
r14                              0x3
r15               0xffffffff8351501e    substchar+0xe738
rip               0xffffffff8336ffa5    db_enter+0x25
cs                               0x8
rflags                         0x246
rsp               0xffff80003c3c3ff0
ss                              0x10
db_enter+0x25:  addq    $0x8,%rsp
ddb{1}>