From: David Howells <dhowells@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: dhowells@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
Andrew Tridgell <tridge@samba.org>,
Eric Paris <eparis@parisplace.org>,
Jakub Jelinek <jakub@redhat.com>,
James Morris <jmorris@namei.org>,
Roland McGrath <roland@redhat.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] signals: check_kill_permission: don't check creds if same_thread_group()
Date: Tue, 18 May 2010 14:50:47 +0100 [thread overview]
Message-ID: <25639.1274190647@redhat.com> (raw)
In-Reply-To: <20100518133925.GA1353@redhat.com>
Oleg Nesterov <oleg@redhat.com> wrote:
> Yes, but both current_cred() and same_thread_group(current, t) call
> get_current(), and gcc doesn't cache the result because we call
> audit_signal_info() in between.
Sorry, yes. I was reading get_current() as current_cred() for some reason.
However, you are _still_ calling get_current() twice... So that bit of your
changelog isn't really correct.
In fact, get_current() should be __attribute_const__ since it can't change
whilst you're looking at it, except within switch_to(), probably in a piece of
assembly code, so gcc should be free to cache it as long as it likes.
David
next prev parent reply other threads:[~2010-05-18 13:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-17 19:54 [PATCH] signals: check_kill_permission: don't check creds if same_thread_group() Oleg Nesterov
2010-05-18 1:25 ` Roland McGrath
2010-05-18 8:55 ` David Howells
2010-05-18 13:39 ` Oleg Nesterov
2010-05-18 13:50 ` David Howells [this message]
2010-05-18 14:08 ` Oleg Nesterov
2010-05-20 19:42 ` Andrew Morton
2010-05-20 20:02 ` Roland McGrath
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