Nonblocking test
setup a c program to fill up the pipe of /dev/pts/$any num
cc -o nonblocking nonblocking.c
./nonblocking
make
ktrace ./wall-test msg
kdump -f ktrace.out
normal test
make
ktrace ./wall-test msg
kdump -f ktrace.out
Set up enotcapable to get coredump
sysctl kern.trap_enotcap=1
sysctl kern.corefile= /tmp/coredumps/%N.core
gdb executable corefile