After reading about removing the execute permission from chmod, I got curious. Is it possible to recover from removing the execute permission from ld-linux.so without rebooting if I haven't yet exited bash? Every command appears to stop functioning.
You would need a statically linked (or already running) utility that can do a
chmod operation. If you had a statically linked BusyBox or a similar emergency shell installed, that would probably do it.
In some old distributions, the basic package management utility (e.g.
rpm) used to be statically linked to enable libc and loader upgrades. Nowadays there are apparently other ways to do that. But if your package management utility happened to be statically linked and the package containing
ld-linux would be still in the cache directory of the package management tools, you might be able to force-reinstall the
ld-linux package and fix it that way.