From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hiroshi Shimamoto Subject: Re: [PATCH -rt] rt-slab: fix cpu inconsistency case Date: Mon, 24 Mar 2008 14:11:00 -0700 Message-ID: <47E818E4.2050602@ct.jp.nec.com> 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=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org To: Steven Rostedt Return-path: Received: from gateway-1237.mvista.com ([63.81.120.158]:40852 "EHLO gateway-1237.mvista.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752086AbYCXVLC (ORCPT ); Mon, 24 Mar 2008 17:11:02 -0400 In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-ID: Steven Rostedt wrote: > 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. > OK, actually, I had a interest in your rework :-) thanks, Hiroshi Shimamoto