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author | Thomas Gleixner <tglx@linutronix.de> | 2010-06-07 17:53:51 +0200 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2010-06-09 17:05:08 +0200 |
commit | 4673247562e39a17e09440fa1400819522ccd446 (patch) | |
tree | 31746ff2cd7f41048b7507cd3cae9dae2a1519be /kernel/irq | |
parent | 84f7586edab93052bbe7eb72e1e9bce5f7b6ae45 (diff) | |
download | linux-stable-4673247562e39a17e09440fa1400819522ccd446.tar.gz linux-stable-4673247562e39a17e09440fa1400819522ccd446.tar.bz2 linux-stable-4673247562e39a17e09440fa1400819522ccd446.zip |
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
Diffstat (limited to 'kernel/irq')
-rw-r--r-- | kernel/irq/manage.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 3164ba7ce151..e1497481fe8a 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; |