From e5d4a35afb1492fe90ba8d8fc783d45c63ff244e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner <tglx@linutronix.de> Date: Mon, 7 Jun 2010 17:53:51 +0200 Subject: [PATCH] genirq: Deal with desc->set_type() changing desc->chip 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 <eha@doredevelopment.dk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: linuxppc-dev <linuxppc-dev@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- kernel/irq/manage.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 986519eb86df..fa4bdd4c5fbc 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -436,6 +436,9 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq, /* 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; -- 2.34.1