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: [kernel-hardening] 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.
WARNING: multiple messages have this Message-ID (diff)
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.o>
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.
WARNING: multiple messages have this Message-ID (diff)
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)
Message-ID: <20170529083904.Tca6sWwcBeZbdSI_omMalQXiSXAoZLxod-c96OFV0n8@z> (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: 46+ 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 ` [kernel-hardening] " Kees Cook
2017-05-27 19:58 ` Kees Cook
2017-05-27 19:58 ` Kees Cook
2017-05-29 8:39 ` Christoph Hellwig [this message]
2017-05-29 8:39 ` Christoph Hellwig
2017-05-29 8:39 ` Christoph Hellwig
2017-05-29 9:11 ` [kernel-hardening] " Eric W. Biederman
2017-05-29 9:11 ` Eric W. Biederman
2017-05-29 9:11 ` Eric W. Biederman
2017-05-29 9:11 ` Eric W. Biederman
2017-05-29 10:24 ` [kernel-hardening] " Peter Zijlstra
2017-05-29 10:24 ` Peter Zijlstra
2017-05-29 10:49 ` [kernel-hardening] " Eric W. Biederman
2017-05-29 10:49 ` Eric W. Biederman
2017-05-29 10:49 ` Eric W. Biederman
2017-05-29 10:49 ` Eric W. Biederman
2017-05-29 11:30 ` [kernel-hardening] " Eric W. Biederman
2017-05-29 11:30 ` Eric W. Biederman
2017-05-29 11:30 ` Eric W. Biederman
2017-05-29 11:30 ` Eric W. Biederman
2017-05-29 11:39 ` [kernel-hardening] " Eric W. Biederman
2017-05-29 11:39 ` Eric W. Biederman
2017-05-29 11:39 ` Eric W. Biederman
2017-05-29 11:39 ` Eric W. Biederman
2017-05-29 12:23 ` [kernel-hardening] " Peter Zijlstra
2017-05-29 12:23 ` Peter Zijlstra
2017-05-29 12:23 ` Peter Zijlstra
2017-05-29 15:43 ` [kernel-hardening] " Peter Zijlstra
2017-05-29 15:43 ` Peter Zijlstra
2017-05-29 15:43 ` Peter Zijlstra
2017-05-29 12:13 ` [kernel-hardening] " Peter Zijlstra
2017-05-29 12:13 ` Peter Zijlstra
2017-05-29 12:13 ` Peter Zijlstra
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