=== dmabugdemo.ko build (stock kernel, unpatched) ===
cc  -O2 -pipe ... -std=gnu11 -Werror -DKLD_MODULE -nostdinc ... -mindirect-branch=thunk-inline   -c /root/poc/dmabuf_demo.c
/root/poc/dmabuf_demo.c:153:20: error: 'SHUT_RDWR' undeclared (first use in this function); did you mean 'O_RDWR'?   [fixed: added #include <sys/socket.h>]
cc  -O2 -pipe ... -c /root/poc/dmabuf_demo.c
cc -Wl,--build-id=sha1 -nostdlib -Wl,--hash-style=sysv   -r -Wl,-d -o dmabugdemo.ko dmabuf_demo.o
=== panic_trigger build ===
cc -O -o panic_trigger panic_trigger.c      (no warnings)