From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] Proper ro_after_init implementation on s390
Date: Wed, 8 Jun 2016 07:41:53 +0200 [thread overview]
Message-ID: <20160608054153.GB3311@osiris> (raw)
In-Reply-To: <CAGXu5jKUSTFOURYaP5J6PangAGFjDv+x17Hr=coJgfCPk8SQsw@mail.gmail.com>
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.
next prev parent reply other threads:[~2016-06-08 5:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 12:06 [PATCH 0/2] Proper ro_after_init implementation on s390 Heiko Carstens
2016-06-07 15:49 ` Kees Cook
2016-06-07 18:07 ` Heiko Carstens
2016-06-07 18:11 ` Kees Cook
2016-06-08 5:41 ` Heiko Carstens [this message]
2016-06-08 15:49 ` Kees Cook
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