Messages in this thread | | | Date | Wed, 8 Jun 2016 07:41:53 +0200 | From | Heiko Carstens <> | Subject | Re: [PATCH 0/2] Proper ro_after_init implementation on s390 |
| |
On Tue, Jun 07, 2016 at 11:11:17AM -0700, Kees Cook wrote: > On Tue, Jun 7, 2016 at 11:07 AM, Heiko Carstens > <heiko.carstens@de.ibm.com> wrote: > > On Tue, Jun 07, 2016 at 08:49:14AM -0700, Kees Cook wrote: > >> > Heiko Carstens (2): > >> > vmlinux.lds.h: allow arch specific handling of ro_after_init data section > >> > s390/mm: add proper __ro_after_init support > >> > > >> > arch/s390/include/asm/cache.h | 3 --- > >> > arch/s390/include/asm/sections.h | 1 + > >> > arch/s390/kernel/vmlinux.lds.S | 12 +++++++++++- > >> > arch/s390/mm/init.c | 7 ++++--- > >> > arch/s390/mm/vmem.c | 7 +++---- > >> > include/asm-generic/vmlinux.lds.h | 10 +++++++++- > >> > 6 files changed, 28 insertions(+), 12 deletions(-) > >> > >> Awesome! This looks great to me! Have you had a chance to look through > >> any of the arch/s390/ __init code for variables that should be marked > >> __ro_after_init? > > > > Not yet, and actually this I'm a bit reluctant to do that, since any wrong > > annotation will lead to kernel crashes sooner or later ;) > > However I'll look into this as well. > > Yup, though the good news is it's usually discovered very quickly. :)
Eventually it might make sense to add something like DEBUG_SECTION_MISMATCH, which would only report on _write_ accesses from non-init sections.
Not sure if this can be done easily and without the need of a new compiler feature. The new problem class I'm afraid of is more or less the same that we had when non-init code referenced (already freed) initdata objects.
| |