From: David Howells <dhowells@redhat.com>
To: Kees Cook <keescook@chromium.org>
Cc: dhowells@redhat.com, "Reshetova,
Elena" <elena.reshetova@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-afs@lists.infradead.org" <linux-afs@lists.infradead.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
Hans Liljestrand <ishkamiel@gmail.com>,
David Windsor <dwindsor@gmail.com>
Subject: Re: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t
Date: Fri, 24 Feb 2017 14:21:45 +0000 [thread overview]
Message-ID: <32460.1487946105@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAGXu5jLVv+_RLth0A=4YGyOWcUv4JsMTpeOWrO3389dTRf-S8g@mail.gmail.com>
Kees Cook <keescook@chromium.org> wrote:
> We can't allow the increment from 0 since it violates the intended
> use-after-free protections.
I would have thought that the protections would've been against the carry flag
getting set.
> If "0" means "still valid" then this
> sounds like it needs a global +1, as Elena suggested in her reply.
This makes it sound like refcount_t is then unsuitable for this.
Since I want to overhaul the code to use more RCU and eliminate some of the
locking, it might be worth waiting on the patches.
David
next prev parent reply other threads:[~2017-02-24 14:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-21 15:43 [PATCH 0/4] fs, afs subsystem refcounter conversions Elena Reshetova
2017-02-21 15:43 ` [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t Elena Reshetova
2017-02-22 16:16 ` David Howells
2017-02-22 17:19 ` Reshetova, Elena
2017-02-22 17:29 ` David Howells
2017-02-22 17:39 ` Kees Cook
2017-02-23 13:32 ` Reshetova, Elena
2017-02-24 14:21 ` David Howells [this message]
2017-02-21 15:43 ` [PATCH 2/4] fs, afs: convert afs_vlocation.usage " Elena Reshetova
2017-02-22 16:22 ` David Howells
2017-02-21 15:43 ` [PATCH 3/4] fs, afs: convert afs_server.usage " Elena Reshetova
2017-02-22 16:32 ` David Howells
2017-02-23 14:05 ` Reshetova, Elena
2017-02-21 15:43 ` [PATCH 4/4] fs, afs: convert afs_volume.usage " Elena Reshetova
2017-02-22 16:34 ` David Howells
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