From: Alexander Potapenko <glider@google.com>
To: Qian Cai <cai@lca.pw>
Cc: Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -next] slub: play init_on_free=1 well with SLAB_RED_ZONE
Date: Tue, 25 Jun 2019 18:16:43 +0200 [thread overview]
Message-ID: <CAG_fn=WuEL0ZGdmy3fhY9gW-nBw_qG9_yb3Ut1+17By3h=d0Jg@mail.gmail.com> (raw)
In-Reply-To: <1561121745.5154.37.camel@lca.pw>
On Fri, Jun 21, 2019 at 2:55 PM Qian Cai <cai@lca.pw> wrote:
>
> On Thu, 2019-06-20 at 18:19 -0700, Kees Cook wrote:
> > On Thu, Jun 20, 2019 at 06:14:33PM -0700, Kees Cook wrote:
> > > On Thu, Jun 20, 2019 at 03:28:01PM -0400, Qian Cai wrote:
> > > > diff --git a/mm/slub.c b/mm/slub.c
> > > > index a384228ff6d3..787971d4fa36 100644
> > > > --- a/mm/slub.c
> > > > +++ b/mm/slub.c
> > > > @@ -1437,7 +1437,7 @@ static inline bool slab_free_freelist_hook(struct
> > > > kmem_cache *s,
> > > > do {
> > > > object = next;
> > > > next = get_freepointer(s, object);
> > > > - memset(object, 0, s->size);
> > > > + memset(object, 0, s->object_size);
> > >
> > > I think this should be more dynamic -- we _do_ want to wipe all
> > > of object_size in the case where it's just alignment and padding
> > > adjustments. If redzones are enabled, let's remove that portion only.
> >
> > (Sorry, I meant: all of object's "size", not object_size.)
> >
>
> I suppose Alexander is going to revise the series anyway, so he can probably
> take care of the issue here in the new version as well. Something like this,
>
> memset(object, 0, s->object_size);
> memset(object, 0, s->size - s->inuse);
Looks like we also need to account for the redzone size. I'm testing
the fix right now.
--
Alexander Potapenko
Software Engineer
Google Germany GmbH
Erika-Mann-Straße, 33
80636 München
Geschäftsführer: Paul Manicle, Halimah DeLaine Prado
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg
prev parent reply other threads:[~2019-06-25 16:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 19:28 [PATCH -next] slub: play init_on_free=1 well with SLAB_RED_ZONE Qian Cai
2019-06-21 1:14 ` Kees Cook
2019-06-21 1:19 ` Kees Cook
2019-06-21 12:55 ` Qian Cai
2019-06-25 16:16 ` Alexander Potapenko [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAG_fn=WuEL0ZGdmy3fhY9gW-nBw_qG9_yb3Ut1+17By3h=d0Jg@mail.gmail.com' \
--to=glider@google.com \
--cc=akpm@linux-foundation.org \
--cc=cai@lca.pw \
--cc=cl@linux.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=penberg@kernel.org \
--cc=rientjes@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).