From: Christoph Hellwig <hch@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Elena Reshetova <elena.reshetova@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Greg KH <gregkh@linuxfoundation.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Ingo Molnar <mingo@redhat.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
arozansk@redhat.com, Davidlohr Bueso <dave@stgolabs.net>,
Manfred Spraul <manfred@colorfullife.com>,
Christoph Hellwig <hch@infradead.org>,
"axboe@kernel.dk" <axboe@kernel.dk>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
"x86@kernel.org" <x86@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
"David S. Miller" <davem@davemloft.net>,
Rik van Riel <riel@redhat.com>,
linux-arch <linux-arch@vger.kernel.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/3] ipc subsystem refcounter conversions
Date: Mon, 29 May 2017 01:39:04 -0700 [thread overview]
Message-ID: <20170529083903.GA17735@infradead.org> (raw)
In-Reply-To: <CAGXu5jKNChaVdfbM171FYkvY1hUMXG6cp-=WAdXBP0eTOO5RAA@mail.gmail.com>
On Sat, May 27, 2017 at 12:58:14PM -0700, Kees Cook wrote:
> FAST_REFCOUNT=n: use function-based refcount_t with cmpxvhg and
> full-verification
> FAST_REFCOUNT=y without arch-specific implementation: use atomic_t
> with no verification (i.e. no functional change from now)
> FAST_REFCOUNT=y with arch-specific implementation: use atomic_t with
> overflow protection
>
> which means FAST_REFCOUNT would need to be default-on so that mm,
> block, net users will remain happy.
>
> Does that sound reasonable?
I'd rather turn the options around so that the atomic_t or fast
arch implementations are the defaul. But either way it needs to
be configurable. Once that is done we can spread refcount_t everywhere
and everyone will be better off, if only for the documentation value
of the type when they use the atomic_t based implementation.
next prev parent reply other threads:[~2017-05-29 8:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-20 11:29 [PATCH 0/3] ipc subsystem refcounter conversions Elena Reshetova
2017-02-20 11:29 ` [PATCH 1/3] ipc: convert ipc_namespace.count from atomic_t to refcount_t Elena Reshetova
2017-05-27 19:41 ` Kees Cook
2017-05-28 12:10 ` Manfred Spraul
2017-02-20 11:29 ` [PATCH 2/3] ipc: convert sem_undo_list.refcnt " Elena Reshetova
2017-05-27 19:44 ` Kees Cook
2017-02-20 11:29 ` [PATCH 3/3] ipc: convert ipc_rcu.refcount " Elena Reshetova
2017-05-27 19:47 ` Kees Cook
2017-02-20 11:42 ` [PATCH 0/3] ipc subsystem refcounter conversions Andy Shevchenko
2017-02-20 12:30 ` Reshetova, Elena
2017-02-22 15:41 ` Davidlohr Bueso
2017-03-04 0:23 ` Andrew Morton
2017-03-06 9:51 ` Reshetova, Elena
2017-05-27 19:58 ` Kees Cook
2017-05-29 8:39 ` Christoph Hellwig [this message]
2017-05-29 9:11 ` Eric W. Biederman
2017-05-29 10:24 ` Peter Zijlstra
2017-05-29 10:49 ` Eric W. Biederman
2017-05-29 11:30 ` Eric W. Biederman
2017-05-29 11:39 ` Eric W. Biederman
2017-05-29 12:23 ` Peter Zijlstra
2017-05-29 15:43 ` Peter Zijlstra
2017-05-29 12:13 ` Peter Zijlstra
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=20170529083903.GA17735@infradead.org \
--to=hch@infradead.org \
--cc=James.Bottomley@hansenpartnership.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=arozansk@redhat.com \
--cc=axboe@kernel.dk \
--cc=dave@stgolabs.net \
--cc=davem@davemloft.net \
--cc=ebiederm@xmission.com \
--cc=elena.reshetova@intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=manfred@colorfullife.com \
--cc=mingo@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=riel@redhat.com \
--cc=serge@hallyn.com \
--cc=x86@kernel.org \
/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).