Kernel Exploit Lab: QEMU + bzImage + rootfs

qemu-system-x86_64 \
  -kernel ./bzImage \            # the compiled kernel image
  -initrd ./rootfs.cpio \        # the initramfs root filesystem
  -append "console=ttyS0 nokaslr quiet" \
  -nographic -m 256M

• Kernel challenges ship as a QEMU setup: a bzImage (kernel), a rootfs.cpio (initramfs), and a run.sh.
• You develop entirely inside this VM — crashing it just reboots a throwaway guest, never the host.
• The run.sh flags tell you the game: is kaslr on, smep/smap on, what cpu features are exposed.
• You get a shell as an unprivileged user; the flag is readable only by root — so you must escalate.