From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754112Ab0JVHEG (ORCPT ); Fri, 22 Oct 2010 03:04:06 -0400 Received: from www.tglx.de ([62.245.132.106]:35804 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752671Ab0JVHEE (ORCPT ); Fri, 22 Oct 2010 03:04:04 -0400 Date: Fri, 22 Oct 2010 09:03:44 +0200 (CEST) From: Thomas Gleixner To: Richard Weinberger cc: peterz@infradead.org, hpa@zytor.com, mingo@elte.hu, "linux-kernel@vger.kernel.org" , linux-next@vger.kernel.org Subject: Re: linux-next: User Mode Linux broken In-Reply-To: <201010212227.12919.richard@nod.at> Message-ID: References: <201010211315.26679.richard@nod.at> <201010212122.38437.richard@nod.at> <201010212227.12919.richard@nod.at> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) 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 On Thu, 21 Oct 2010, Richard Weinberger wrote: > Am Donnerstag 21 Oktober 2010, 21:45:35 schrieb Thomas Gleixner: > > Why shold it solve it ? irq_enable is set to compat_irq_enable which > > in turn calls chip->enable. > > > > So how's that different ? > > I took a closer look on the issue. > > check_irq_resend() gets called before irq_chip_set_defaults(). > In the first call to check_irq_resend() desc->irq_data.chip->irq_enable is > NULL. UML dies due to a NULL-pointer dereference... > > I don't know why check_irq_resend() is called before irq_chip_set_defaults(). > It's your code. ;-) Well, but it only gets called via enable_irq(). So that means something is calling enable_irq _before_ request/setup_irq(). arch/um/kernel/irq.c:init_IRQ() does that :) Thanks, tglx