From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757745AbZHQLMN (ORCPT ); Mon, 17 Aug 2009 07:12:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757724AbZHQLMM (ORCPT ); Mon, 17 Aug 2009 07:12:12 -0400 Received: from www.tglx.de ([62.245.132.106]:55884 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751238AbZHQLMM (ORCPT ); Mon, 17 Aug 2009 07:12:12 -0400 Date: Mon, 17 Aug 2009 13:12:09 +0200 (CEST) From: Thomas Gleixner To: Michael Buesch cc: linux-kernel@vger.kernel.org Subject: Re: Threaded interrupt handlers broken? In-Reply-To: Message-ID: References: <200908161153.14081.mb@bu3sch.de> <200908162301.21775.mb@bu3sch.de> <200908171223.57412.mb@bu3sch.de> 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 Mon, 17 Aug 2009, Thomas Gleixner wrote: > On Mon, 17 Aug 2009, Thomas Gleixner wrote: > > > On Mon, 17 Aug 2009, Michael Buesch wrote: > > > Ok, I added some more debugging code: > > > http://bu3sch.de/patches/wireless-testing/20090817-1219/patches/001-hack-threaded-irqs.patch > > > > > > Here's the result: > > > http://bu3sch.de/misc/dmesg2 > > > > > > Is it possible that the irq_to_desc() in irq_thread() fails and the > > > resulting desc pointer points to something random? That could > > > probably explain why the bit is set and why the spinlock is > > > uninitialized. But it would not explain why desc->lock would still > > > work... Maybe irq_to_desc() returns a descriptor to another irq (!= > > > 52)? > > > > That would cause the whole irq code to fail. Can you send/upload your > > .config please ? > > Also just add printk("desc: %p \n", desc); to the various places to > make sure that your pointers are correct. Gah. I think I found it. I wonder why nobody else ever tripped over this. Thanks, tglx --- diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index d222515..223b062 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -607,7 +607,6 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) */ get_task_struct(t); new->thread = t; - wake_up_process(t); } /* @@ -712,6 +711,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) new->dir = NULL; register_handler_proc(irq, new); + if (new->thread) + wake_up_process(new->thread); + return 0; mismatch: