Why does this Rust program leak memory?

Follow me on Mastodon: https://hachyderm.io/@fasterthanlime
Support my work: https://fasterthanli.me/donate

Thanks to Omer from Egypt for submitting this question: https://github.com/mariocynicys/mem-hog
Submit your own questions: https://fasterthanli.me/submit

Making our own executable packer: https://fasterthanli.me/series/making...

Contents
00:00 What does the program do?
04:35 Memory usage, Vec, and jemalloc
06:18 How does malloc even work?
07:22 Visualizing allocations with memusage
11:14 Where is the heap? /proc/PID/maps
14:24 Virtual memory vs RSS
16:00 Tracing syscalls with strace
19:50 Virtual memory vs physical memory
20:50 The madvise syscall
22:31 What's technique 2 doing?
23:37 Iterator size hints
24:56 What's technique 3 doing?
30:31 Mystery solved
34:53 Thanks & outro