Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750857AbWH3LzY (ORCPT ); Wed, 30 Aug 2006 07:55:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750844AbWH3LzY (ORCPT ); Wed, 30 Aug 2006 07:55:24 -0400 Received: from scrub.xs4all.nl ([194.109.195.176]:13278 "EHLO scrub.xs4all.nl") by vger.kernel.org with ESMTP id S1750821AbWH3LzX (ORCPT ); Wed, 30 Aug 2006 07:55:23 -0400 Date: Wed, 30 Aug 2006 13:54:51 +0200 (CEST) From: Roman Zippel X-X-Sender: roman@scrub.home To: Oleg Nesterov cc: Kirill Korotaev , Andrew Morton , Linux Kernel Mailing List , Alan Cox , Christoph Hellwig , Pavel Emelianov , Andrey Savochkin , devel@openvz.org, Rik van Riel , Andi Kleen , Alexey Dobriyan , Matt Helsley , CKRM-Tech Subject: Re: [PATCH 1/7] introduce atomic_dec_and_lock_irqsave() In-Reply-To: <20060830155140.GA193@oleg> Message-ID: References: <44F45045.70402@sw.ru> <44F4540C.8050205@sw.ru> <20060830145759.GA163@oleg> <20060830155140.GA193@oleg> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 785 Lines: 21 Hi, On Wed, 30 Aug 2006, Oleg Nesterov wrote: > > AFAICT it's called via rcu, does that mean anything released via rcu has > > to be protected against interrupts? > > RCU means softirq, probably we can use spin_lock_bh() to protect against deadlock. > But free_uid() may be called with irqs disabled, we can't use local_bh_enable() > in such a case. Eek, I wasn't really aware of it and this would really suck. We should move things out of the interrupt context and not into it. :( I would call it a bug in the rcu system. bye, Roman - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/