Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760481Ab0G3TJM (ORCPT ); Fri, 30 Jul 2010 15:09:12 -0400 Received: from kroah.org ([198.145.64.141]:51528 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756046Ab0G3RS3 (ORCPT ); Fri, 30 Jul 2010 13:18:29 -0400 X-Mailbox-Line: From gregkh@clark.site Fri Jul 30 10:15:04 2010 Message-Id: <20100730171504.200218674@clark.site> User-Agent: quilt/0.48-11.2 Date: Fri, 30 Jul 2010 10:14:38 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Thomas Gleixner , Benjamin Herrenschmidt , linuxppc-dev Subject: [050/165] genirq: Deal with desc->set_type() changing desc->chip In-Reply-To: <20100730171550.GA1299@kroah.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2269 Lines: 60 2.6.32-stable review patch. If anyone has any objections, please let us know. ------------------ From: Thomas Gleixner commit 4673247562e39a17e09440fa1400819522ccd446 upstream. The set_type() function can change the chip implementation when the trigger mode changes. That might result in using an non-initialized irq chip when called from __setup_irq() or when called via set_irq_type() on an already enabled irq. The set_irq_type() function should not be called on an enabled irq, but because we forgot to put a check into it, we have a bunch of users which grew the habit of doing that and it never blew up as the function is serialized via desc->lock against all users of desc->chip and they never hit the non-initialized irq chip issue. The easy fix for the __setup_irq() issue would be to move the irq_chip_set_defaults(desc->chip) call after the trigger setting to make sure that a chip change is covered. But as we have already users, which do the type setting after request_irq(), the safe fix for now is to call irq_chip_set_defaults() from __irq_set_trigger() when desc->set_type() changed the irq chip. It needs a deeper analysis whether we should refuse to change the chip on an already enabled irq, but that'd be a large scale change to fix all the existing users. So that's neither stable nor 2.6.35 material. Reported-by: Esben Haabendal Signed-off-by: Thomas Gleixner Cc: Benjamin Herrenschmidt Cc: linuxppc-dev Signed-off-by: Greg Kroah-Hartman --- kernel/irq/manage.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -436,6 +436,9 @@ int __irq_set_trigger(struct irq_desc *d /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */ desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK); desc->status |= flags; + + if (chip != desc->chip) + irq_chip_set_defaults(desc->chip); } return ret; -- 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/