From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967153AbXILLSV (ORCPT ); Wed, 12 Sep 2007 07:18:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965842AbXILLSK (ORCPT ); Wed, 12 Sep 2007 07:18:10 -0400 Received: from cerber.ds.pg.gda.pl ([153.19.208.18]:40238 "EHLO cerber.ds.pg.gda.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965366AbXILLSJ (ORCPT ); Wed, 12 Sep 2007 07:18:09 -0400 Date: Wed, 12 Sep 2007 12:17:58 +0100 (BST) From: "Maciej W. Rozycki" To: Andrew Morton , David Woodhouse cc: linux-kernel@vger.kernel.org Subject: [PATCH] free_irq(): Actually handle DEBUG_SHIRQ Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Code used for DEBUG_SHIRQ in free_irq() is unreachable -- the for() loop within never terminates otherwise than by return. This is an obvious fix. Signed-off-by: Maciej W. Rozycki --- Please apply. While at it, I have a question about the complementary code within request_irq(): when the option in question is enabled, a spurious IRQ is posted before internal setup is done by setup_irq(). This includes the ->depth counter. Now if the interrupt handler of some driver calls disable_irq_nosync(), then code in setup_irq() will mess up the state of ->depth afterwards if this is the first handler being installed (i.e. within the "if (!shared)" block). This is reported later on when enable_irq() called by the driver, by means of a message like this: Unbalanced enable for IRQ 34 WARNING: at kernel/irq/manage.c:158 enable_irq() Now given DEBUG_SHIRQ is a debug facility, not to be normally used for production, is the phenomenon as described considered a design limitation we can live with, or is it a bug that qualifies for a fix? I can reproduce this problem easily with phylib. Maciej patch-mips-2.6.23-rc5-20070904-debug-shirq-0 diff -up --recursive --new-file linux-mips-2.6.23-rc5-20070904.macro/kernel/irq/manage.c linux-mips-2.6.23-rc5-20070904/kernel/irq/manage.c --- linux-mips-2.6.23-rc5-20070904.macro/kernel/irq/manage.c 2007-09-04 04:56:21.000000000 +0000 +++ linux-mips-2.6.23-rc5-20070904/kernel/irq/manage.c 2007-09-11 23:58:59.000000000 +0000 @@ -448,7 +448,7 @@ void free_irq(unsigned int irq, void *de if (action->flags & IRQF_SHARED) handler = action->handler; kfree(action); - return; + break; } printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq); spin_unlock_irqrestore(&desc->lock, flags);