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From: David Howells <dhowells@redhat.com>
In-Reply-To: <20100409195936.44663BD18@magilla.sf.frob.com>
References: <20100409195936.44663BD18@magilla.sf.frob.com> <20100322184136.GA3967@redhat.com> <15829.1269333449@redhat.com> <20100323105707.GA8634@redhat.com>
To: Roland McGrath <roland@redhat.com>
Cc: dhowells@redhat.com, Oleg Nesterov <oleg@redhat.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Alexey Dobriyan <adobriyan@gmail.com>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH -mm 3/3] proc: make task_sig() lockless
Date: Sat, 10 Apr 2010 09:16:19 +0100
Message-ID: <9905.1270887379@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 665
Lines: 15

Roland McGrath <roland@redhat.com> wrote:

> I'm not so sure.  Operations like sigprocmask and sigaction really have
> always been entirely atomic from the userland perspective before.  Now it
> becomes possible to read from /proc e.g. a blocked set that never existed
> as such (one word updated by sigprocmask but not yet the next word).

If you have a small userspace buffer, that was previously possible too.

David
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