Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762630AbYJJUYu (ORCPT ); Fri, 10 Oct 2008 16:24:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761959AbYJJUYk (ORCPT ); Fri, 10 Oct 2008 16:24:40 -0400 Received: from adelie.canonical.com ([91.189.90.139]:43675 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761647AbYJJUYk (ORCPT ); Fri, 10 Oct 2008 16:24:40 -0400 Message-ID: <48EFB9F8.2060406@canonical.com> Date: Fri, 10 Oct 2008 16:24:24 -0400 From: Stefan Bader User-Agent: Thunderbird 2.0.0.17 (X11/20080925) MIME-Version: 1.0 To: Greg KH CC: stable@kernel.org, Thomas Gleixner , Ingo Molnar , Yinghai Lu , linux-kernel@vger.kernel.org, "H. Peter Anvin" Subject: Re: [stable] [PATCH] x86: Reserve FIRST_DEVICE_VECTOR in used_vectors bitmap References: <48EFB4B2.2020508@canonical.com> <20081010201805.GC32164@kroah.com> In-Reply-To: <20081010201805.GC32164@kroah.com> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1296 Lines: 35 Greg KH wrote: > On Fri, Oct 10, 2008 at 04:01:54PM -0400, Stefan Bader wrote: >> Affected: 2.6.24-2.6.27 >> >> Someone from the community found out, that after repeatedly unloading and >> loading a device driver that uses MSI IRQs, the system eventually assigned >> the vector initially reserved for IRQ0 to the device driver. >> >> The reason for this is, that although IRQ0 is tied to the FIRST_DEVICE_VECTOR >> when declaring the irq_vector table, the corresponding bit in the used_vectors >> map is not set. So, if vectors are released and assigned often enough, the >> vector will get assigned to another interrupt. This happens more often with >> MSI interrupts as those are exclusively using a vector. > > Is there a problem with being assigned to IRQ0 in situations like this? > > thanks, > > greg k-h Yes, since IRQ0 is still wanted and used by the system timer. After the module get unloaded again, the vector gets freed and no timer interrupt is delivered anymore. Stefan -- When all other means of communication fail, try words! -- 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/