emacs version is 27.2 (Installed using dnf on fedora 35 system)

test file: https://github.com/torvalds/linux/blob/v5.16/kernel/events/core.c

Step1: emacs -Q kernel/events/core.c
Step2: eval "(font-lock-mode 0)"
Step3: eval "(highlight-regexp "static")"

The "static" keyword at the end of the file is not highlighted.