From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from coco.kroah.org (kroah.org [198.145.64.141]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "coco.kroah.org", Issuer "Greg KH" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 6D682B70C3 for ; Wed, 28 Jul 2010 10:34:41 +1000 (EST) Subject: Patch "genirq: Deal with desc->set_type() changing desc->chip" has been added to the 2.6.32-stable tree To: tglx@linutronix.de, benh@kernel.crashing.org, eha@doredevelopment.dk, gregkh@suse.de, linuxppc-dev@ozlabs.org From: Date: Tue, 27 Jul 2010 17:33:06 -0700 Message-ID: <12802771863933@site> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Cc: stable@kernel.org, stable-commits@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a note to let you know that I've just added the patch titled genirq: Deal with desc->set_type() changing desc->chip to the 2.6.32-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: genirq-deal-with-desc-set_type-changing-desc-chip.patch and it can be found in the queue-2.6.32 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 4673247562e39a17e09440fa1400819522ccd446 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 7 Jun 2010 17:53:51 +0200 Subject: genirq: Deal with desc->set_type() changing desc->chip 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; Patches currently in stable-queue which might be from tglx@linutronix.de are queue-2.6.32/genirq-deal-with-desc-set_type-changing-desc-chip.patch