linux-kernel - Re: while_each_thread() under 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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20100619191909.GA4384@redhat.com>
Date:	Sat, 19 Jun 2010 21:19:09 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Mandeep Baines <msb@...gle.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Don Zickus <dzickus@...hat.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...e.hu>,
	Jerome Marchand <jmarchan@...hat.com>,
	Roland McGrath <roland@...hat.com>,
	linux-kernel@...r.kernel.org, stable@...nel.org,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: Re: while_each_thread() under rcu_read_lock() is broken?

On 06/18, Mandeep Baines wrote:
>
> On Fri, Jun 18, 2010 at 12:34 PM, Oleg Nesterov <oleg@...hat.com> wrote:
> >
> >
> > I _really_ hope I missed something, will recheck tomorrow with the fresh
> > head. Still I'd like to share my concerns...
>
> Yep. You're right. Not sure what I was thinking. This is only case
> where do_each_thread
> is protected by an rcu_read_lock. All others, correctly use read_lock.

No, no. while_each_thread() is supposed to be rcu-safe, we should fix it.
It has many rcu_read_lock() users.

The patch which fixes rcu_lock_break() is orthogonal to this problem.

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/