I decided to read ep1[0] too and I saw a picture "use all the memory". I don't know if it's funnier that I checked if you have an "alt" HTML tag or that you actually wrote the text from the picture. People with alt tags are MVPs. :)<p>[0] - <a href="https://brennan.io/2016/10/13/kernel-dev-ep1/" rel="nofollow">https://brennan.io/2016/10/13/kernel-dev-ep1/</a>
Thoroughly enjoyed the tutorial, but why would one want to make a custom system call? What superpowers does this give you? Thanks in advance for your answers.
Hmm... This is certainly very interesting. Can anyone think of any neat kernel-only things that one might implement for kicks as a learning project? Particularly for someone who hasn't done kernel programming? It could definitely be a silly thing, but probably more useful than printing to the kernel log.
One correction to the strncpy_from_user part, specifically this:<p>> The process could try to read another process’s memory by giving a pointer that maps into another process’s address space.<p>This cannot happen, there is no such thing as "a pointer that maps into another process's address space". A virtual address in Linux (on x86 and probably almost all arches) accesses either the processes own memory map (where access to unmapped addresses causes a fault even when done from ring 0) or the kernel virtual mapping.