kernel: page fault trap, code=10
Stopped at      0    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*481975  20642      0   0x8000000  0x4000000    0  syz-executor.6
0(ffff800000da5000,b,fffffd806b1c5e80,ffff800030f39340,1220,0) at 0
rtrequest(b,ffff800030f393e8,3,ffff800030f39488,0) at rtrequest+0x9dc sys/net/route.c:1103
rt_match(ffff800030f395e0,ffff800030f395fc,1,0) at rt_match+0xc3 rt_clone sys/net/route.c:383 [inline]
rt_match(ffff800030f395e0,ffff800030f395fc,1,0) at rt_match+0xc3 sys/net/route.c:358
route_mpath(ffff800030f395c8,fffffd806909eff8,fffffd806909eff4,0) at route_mpath+0x8b sys/net/route.c:255
in_ouraddr(fffffd806909ef00,ffff800000dd2800,ffff800030f395c8) at in_ouraddr+0x98 sys/netinet/ip_input.c:830
ip_input_if(ffff800030f396b8,ffff800030f396c4,ffff80002bd16000,0,ffff800000dd2800) at ip_input_if+0x25e sys/netinet/ip_input.c:486
ipv4_input(ffff800000dd2800,fffffd806909ef00) at ipv4_input+0x47 sys/netinet/ip_input.c:327
ether_input(ffff800000dd2800,fffffd806909ef00) at ether_input+0x525
tun_dev_write(5d06,ffff800030f39a38,ffff80002bd16000,2) at tun_dev_write+0x209 sys/net/if_tun.c:914
spec_write(ffff800030f39890) at spec_write+0xd8 sys/kern/spec_vnops.c:302
VOP_WRITE(fffffd80589193c0,ffff800030f39a38,11,fffffd807f7d7618) at VOP_WRITE+0xc3 sys/kern/vfs_vops.c:245
vn_write(fffffd806a74aa50,ffff800030f39a38,0) at vn_write+0x157 sys/kern/vfs_vnops.c:408
dofilewritev(ffff80002a67d9c0,c8,ffff800030f39a38,0,ffff800030f39af0) at dofilewritev+0x1a9 sys/kern/sys_generic.c:375
sys_write(ffff80002a67d9c0,ffff800030f39ba0,ffff800030f39af0) at sys_write+0x87 sys/kern/sys_generic.c:295
syscall(ffff800030f39ba0) at syscall+0x72a sys/arch/amd64/amd64/trap.c:577
end trace frame: 0xffff800030f39c20, count: 0
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.