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authorThomas Gleixner <tglx@linutronix.de>2010-06-07 17:53:51 +0200
committerThomas Gleixner <tglx@linutronix.de>2010-06-09 17:05:08 +0200
commit4673247562e39a17e09440fa1400819522ccd446 (patch)
tree31746ff2cd7f41048b7507cd3cae9dae2a1519be
parent84f7586edab93052bbe7eb72e1e9bce5f7b6ae45 (diff)
downloadlinux-2.6.34-ux500-4673247562e39a17e09440fa1400819522ccd446.tar.gz
genirq: Deal with desc->set_type() changing desc->chip
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> Cc: stable@kernel.org
-rw-r--r--kernel/irq/manage.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 3164ba7ce15..e1497481fe8 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -456,6 +456,9 @@ 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;