This is a note to let you know that I've just added the patch titled
genirq: Prevent irq storm on migration
to the 2.6.37-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-prevent-irq-storm-on-migration.patch
and it can be found in the queue-2.6.37 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From f1a06390d013244e721372b3f9b66e39b6429c71 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <[email protected]>
Date: Fri, 28 Jan 2011 08:47:15 +0100
Subject: genirq: Prevent irq storm on migration
From: Thomas Gleixner <[email protected]>
commit f1a06390d013244e721372b3f9b66e39b6429c71 upstream.
move_native_irq() masks and unmasks the interrupt line
unconditionally, but the interrupt line might be masked due to a
threaded oneshot handler in progress. Unmasking the line in that case
can lead to interrupt storms. Observed on PREEMPT_RT.
Originally-from: Ingo Molnar <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/irq/migration.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
--- a/kernel/irq/migration.c
+++ b/kernel/irq/migration.c
@@ -56,6 +56,7 @@ void move_masked_irq(int irq)
void move_native_irq(int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
+ bool masked;
if (likely(!(desc->status & IRQ_MOVE_PENDING)))
return;
@@ -63,8 +64,15 @@ void move_native_irq(int irq)
if (unlikely(desc->status & IRQ_DISABLED))
return;
- desc->irq_data.chip->irq_mask(&desc->irq_data);
+ /*
+ * Be careful vs. already masked interrupts. If this is a
+ * threaded interrupt with ONESHOT set, we can end up with an
+ * interrupt storm.
+ */
+ masked = desc->status & IRQ_MASKED;
+ if (!masked)
+ desc->irq_data.chip->irq_mask(&desc->irq_data);
move_masked_irq(irq);
- desc->irq_data.chip->irq_unmask(&desc->irq_data);
+ if (!masked)
+ desc->irq_data.chip->irq_unmask(&desc->irq_data);
}
-
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.37/genirq-prevent-irq-storm-on-migration.patch
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