Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754601AbYCXUkw (ORCPT ); Mon, 24 Mar 2008 16:40:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752557AbYCXUkp (ORCPT ); Mon, 24 Mar 2008 16:40:45 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:42958 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752066AbYCXUko (ORCPT ); Mon, 24 Mar 2008 16:40:44 -0400 Date: Mon, 24 Mar 2008 16:40:43 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Hiroshi Shimamoto cc: Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: [PATCH -rt] rt-slab: fix cpu inconsistency case In-Reply-To: Message-ID: References: <47E2A63B.4020003@ct.jp.nec.com> <47E2C4CC.5050401@ct.jp.nec.com> <47E41EDB.7030908@ct.jp.nec.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1184 Lines: 40 On Mon, 24 Mar 2008, Steven Rostedt wrote: > > On Fri, 21 Mar 2008, Hiroshi Shimamoto wrote: > > > > > > > > Is this a bug in mainline? The !PREEMPT_RT case should be as close to > > > mainline as possible, with no actual changes in object code. If this is > > > not the case, then we need to fix that. > > > > No, this issue is in -rt only. > > > > Hi Hiroshi, > > Thanks again for reporting this. I took a deeper look into this today and > came to the conclusion that we need to get rid of both > slab_irq_disable_nort and slab_irq_disable_rt, and simply use > slab_irq_disable ;-) > > This is what you patch indirectly does. I'll write up another patch to fix > this. > Actually, I'm going to take your patch. Seems that the reason Ingo did the two separate, is that the functions called also call the slab_irq_save, which will retake the locks in PREEMPT_RT. If we don't release the lock, then we can deadlock. Thanks, -- Steve -- 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/