On Mon, Mar 30, 2020 at 06:17:32PM +0200, Jann Horn wrote: > On Mon, Mar 30, 2020 at 5:59 PM Alexei Starovoitov > <alexei.starovoitov@xxxxxxxxx> wrote: > > On Mon, Mar 30, 2020 at 8:14 AM Jann Horn <jannh@xxxxxxxxxx> wrote: > > > > > > I noticed that CONFIG_DEBUG_INFO_BTF seems to partly defeat the point > > > of CONFIG_GCC_PLUGIN_RANDSTRUCT. > > > > Is it a theoretical stmt or you have data? > > I think it's the other way around. > > gcc-plugin breaks dwarf and breaks btf. > > But I only looked at gcc patches without applying them. > > Ah, interesting - I haven't actually tested it, I just assumed > (perhaps incorrectly) that the GCC plugin would deal with DWARF info > properly. Yeah, GCC appears to create DWARF before the plugin does the randomization[1], so it's not an exposure, but yes, struct randomization is pretty completely incompatible with a bunch of things in the kernel (by design). I'm happy to add negative "depends" in the Kconfig if it helps clarify anything. -Kees [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84052 -- Kees Cook
