linux-kernel - Re: linux-next 20111025: warnings in rcu_idle_exit_common()/rcu_idle_enter

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <1320245786.4793.32.camel@gandalf.stny.rr.com>
Date:	Wed, 02 Nov 2011 10:56:26 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	paulmck@...ux.vnet.ibm.com
Cc:	Wu Fengguang <fengguang.wu@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Carsten Emde <cbe@...dl.org>
Subject: Re: linux-next 20111025: warnings in
 rcu_idle_exit_common()/rcu_idle_enter_common()

On Wed, 2011-11-02 at 07:44 -0700, Paul E. McKenney wrote:

> rcu: Fix idle-task checks
> 
> RCU has traditionally relied on idle_cpu() to determine whether a given
> CPU is running in the context of an idle task, but recent changes have
> invalidated this approach.

Correct. idle_cpu() returns if the CPU is idle or not, not if the CPU is
running the idle thread. If the CPU wakes up on the idle thread and
there's tasks on the run queue, then idle_cpu() will return false, even
though the task running is the idle thread. But the CPU itself is not
technically idle.

Acked-by: Steven Rostedt <rostedt@...dmis.org>

-- Steve




--
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/