linux-kernel - Re: [PATCH percpu/for-3.11] percpu-refcount: consistently use plain (non-sched) RCU

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]

Date:	Wed, 12 Jun 2013 13:55:00 -0700
From:	Kent Overstreet <koverstreet@...gle.com>
To:	Tejun Heo <theo@...hat.com>
Cc:	linux-kernel@...r.kernel.org,
	Rusty Russell <rusty@...tcorp.com.au>,
	Oleg Nesterov <oleg@...hat.com>,
	Christoph Lameter <cl@...ux-foundation.org>
Subject: Re: [PATCH percpu/for-3.11] percpu-refcount: consistently use plain
 (non-sched) RCU

On Wed, Jun 12, 2013 at 01:40:32PM -0700, Tejun Heo wrote:
> From e96262150a513ce3d54ff221d4ace8aeec96e0bf Mon Sep 17 00:00:00 2001
> From: Tejun Heo <tj@...nel.org>
> Date: Wed, 12 Jun 2013 13:37:42 -0700
> 
> percpu_ref_get/put() are using preempt_disable/enable() while
> percpu_ref_kill() is using plain call_rcu() instead of
> call_rcu_sched().  This is buggy as grace periods of the two may not
> match.  Fix it by using plain RCU in percpu_ref_get/put().
> 
> (I suggested using sched RCU in the first place but there's no actual
>  benefit in doing so unless we're gonna introduce different variants
>  of get/put to be called while preemption is alredy disabled, which we
>  definitely shouldn't.)
> 
> Signed-off-by: Tejun Heo <tj@...nel.org>
> Reported-by: Rusty Russell <rusty@...tcorp.com.au>

Acked-by: Kent Overstreet <koverstreet@...gle.com>
--
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/