linux-kernel - Re: [PATCH 0/1] aio: change exit_aio() to load mm->ioctx_table once and avoid rcu_read

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140429194900.GA2998@redhat.com>
Date:	Tue, 29 Apr 2014 21:49:00 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Benjamin LaHaise <bcrl@...ck.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Kent Overstreet <kmo@...erainc.com>,
	Al Viro <viro@...iv.linux.org.uk>, linux-aio@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/1] aio: change exit_aio() to load mm->ioctx_table
	once and avoid rcu_read_lock()

On 04/29, Benjamin LaHaise wrote:
>
> On Tue, Apr 29, 2014 at 08:39:15PM +0200, Oleg Nesterov wrote:
> >
> > Kent, could you also explain kioctx->dead is atomic_t? This looks
> > pointless? afaics atomic_ buys nothing in this case.
>
> If it wasn't atomic, it would need to be volatile.

Then ACCESS_ONCE() in aio_read_events() makes more sense. Although
I can't say I understand why it is needed.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/