[$] Safer flexible arrays for the kernel

At the 2022 Linux
Security Summit Europe (LSS EU), Gustavo A. R. Silva reported in on
work he has been doing on 'flexible' arrays in the kernel. While these
arrays provide some... flexibility... they are also a source of bugs,
which
can often result in security vulnerabilities. He has been working on ways
to make the use of flexible arrays safer in the kernel.