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: <20140730150724.GK11241@linux.vnet.ibm.com>
Date:	Wed, 30 Jul 2014 08:07:24 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Lai Jiangshan <laijs@...fujitsu.com>
Cc:	linux-kernel@...r.kernel.org, mingo@...nel.org,
	dipankar@...ibm.com, akpm@...ux-foundation.org,
	mathieu.desnoyers@...icios.com, josh@...htriplett.org,
	tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
	dhowells@...hat.com, edumazet@...gle.com, dvhart@...ux.intel.com,
	fweisbec@...il.com, oleg@...hat.com, bobby.prani@...il.com
Subject: Re: [PATCH RFC tip/core/rcu 1/9] rcu: Add call_rcu_tasks()

On Wed, Jul 30, 2014 at 02:52:41PM +0800, Lai Jiangshan wrote:
> On 07/29/2014 06:56 AM, Paul E. McKenney wrote:
> 
> > +		/*
> > +		 * Each pass through the following loop scans the list
> > +		 * of holdout tasks, removing any that are no longer
> > +		 * holdouts.  When the list is empty, we are done.
> > +		 */
> > +		while (!list_empty(&rcu_tasks_holdouts)) {
> > +			schedule_timeout_interruptible(HZ / 10);
> > +			flush_signals(current);
> > +			rcu_read_lock();
> > +			list_for_each_entry_rcu(t, &rcu_tasks_holdouts,
> > +						rcu_tasks_holdout_list) {
> > +				if (smp_load_acquire(&t->rcu_tasks_holdout))
> > +					continue;
> > +				list_del_init(&t->rcu_tasks_holdout_list);
> > +				/* @@@ need to check for usermode on CPU. */
> > +			}
> > +			rcu_read_unlock();
> 
> Maybe I missed something. The task @t may already exited and we access to
> the stale memory here if without patch 8/9.

Yep, patch 8/9 is not optional.

							Thanx, Paul

--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ