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 <sta...@kernel.org> know about it.
>From 4673247562e39a17e09440fa1400819522ccd446 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <t...@linutronix.de>
Date: Mon, 7 Jun 2010 17:53:51 +0200
Subject: genirq: Deal with desc->set_type() changing desc->chip
From: Thomas Gleixner <t...@linutronix.de>
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 <e...@doredevelopment.dk>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: linuxppc-dev <linuxppc-...@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gre...@suse.de>
---
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 t...@linutronix.de are
queue-2.6.32/genirq-deal-with-desc-set_type-changing-desc-chip.patch
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